, I lit. ,1! I fipklrzlvl’ . .17‘: Pl .7 x If 7, hf; Wyn“ H.113. : $3. yup-w , x ‘01.. 5.. 3:1. .v. in: 1%. in! 9... . Ir , .1 f3 ; u. ,.,fi§m. "nae" a. . .5 {un- This is to certify that the thesis entitled FEEDLOT PERFORMANCE, CARCASS AND PALATABILITY TRAITS, AS WELL AS SUBSEQUENT ECONOMIC RELEVANCE IN CALF-FED AND YEARLING HOLSTEINS AND ANGUS STEERS presented by Cassie S. Abney has been accepted towards fulfillment of the requirements for the MS. degree in Animal Science Major Professor’s Signature 1+- / 5L - 0% Date MSU is an Affirmative Action/Equal Opportunity Institution .-—---.—.-_-_-_-.—--.~A‘_L-I-n.-o—n—o---n-ogo—‘cnn—n—g—g_-_o-—c—.—o—._ -.—._.-......_-_-_-_..._-_.._-_-—--—--—¢—-_._-~- _ UBRARY l Michigan State University PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 6/01 c:/CIRC/DateDue.p65-p.15 FEEDLOT PERFORMANCE, CARCAss AND PALATABlLlTY TRAITS, As WELL As SUBSEQUENT ECONOMIC RELEVANCE IN CALF-FED AND YEARLINO HOLSTEINS ANo ANGUS STEERS By Cassie S. Abney A Thesis Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Animal Science 2004 ABSTRACT FEEDLOT PERFORMANCE, CARCASS AND PALATABILITY TRAITS, AS WELL AS SUBSEQUENT ECONOMIC RELEVANCE IN CALF-FED AND YEARLING HOLSTEINS AND ANGUS STEERS By Cassie S. Abney Implanted Holstein calf-feds (IHC; n=70), non-implanted Holstein calf-feds (NHC; n=70), Angus/black calf-feds (BC; n=70), Holstein yearlings (HY; n=90), and Angus/black yearlings (BY; n=110) were compared to determine feedlot performance, carcass traits and palatability differences due to breed. Each breed group was harvested at two fat thickness endpoints (0.762 and 1.016 cm for Holsteins and 1.016 and 1.27 cm for Angus). Angus cattle were more efficient and gained faster (P<0.01) than Holstein in both finishing systems, while HY consumed 7.2% more feed than BY. Similarly IHC consumed more, were more efficient, and gained faster (P<0.01) than NHC. Angus cattle had higher dressing percent, larger ribeyes, and less kidney, pelvic and heart fat (P<0.01) and higher yield grades than Holstein cattle. HY had higher quality grades and marbling scores than BY. HY displayed advantages (P<0.03) in tenderness, amount of connective tissue, and shear force values over BY. BC and NHC were similar in terms of sensory and shear force values, however, BC rated significantly better (P<0.03) than IHC for tenderness, amount of connective tissue and shear force. Holstein steers had the advantage in carcass value with the exception of NHC, while Angus had a lower cost of gain and higher gross margin. Keywords: Angus, calf-feds, feedlot performance, Holstein, yearlings, implants ACKNOWLEDGMENTS I would like to express my deepest gratitude to my major advisors, Dr. Steven Rust and Dr. Harlan Ritchie. Dr. Rust provided advice in research and scholastic activities that was crucial to my success at Michigan State. He was always willing to answer questions and provided the proper direction regarding all of my research endeavors. Dr. Ritchie’s advice, input and encouragement was second to none. He is one of the industry leaders in beef cattle production and having the Opportunity to interact and learn from him was a once in a lifetime opportunity. The support and friendship provided by both Dr. Rust and Dr. Ritchie is something I will be forever grateful for. I would also like to thank Dr. Matt Doumit for his technical assistance with the meat science portion of my project and the many hours he spent helping at the packing plant and in the meat lab. Additionally, I would like to thank Dr. Dave Hawkins for assistance not only on my thesis committee, but also for his mentoring and direction with my teaching assistant responsibilities. Lastly, I would like to thank Dr. Gerald Schwab for his service on my committee and his input on the economic aspects of this project. This project would not have been possible without the help of many people. I would like to express my sincere gratitude to Ken Metz, John Buffington, Fred Openlander, Phil Summer and all the staff at the Beef Cattle Teaching and Research Center. You guys were awesome. A special thanks goes to Andrew MCPeake for all your help and guidance over the last two years. iii Additionally, I would like to thank Emilio Ungerfeld, Jeff Mafi, Nick Berry, Mike Rincker and Chuck Allison for their assistance with data collection and lab assistance. To my undergraduate assistants, Genevieve Davis and Kohl Schrader, for all your hard work in the lab and countless hours you spent in the cold grinding up meat samples. I would like to thank Tom Forton, Jennifer Dominguez and the meat lab staff for their hard work and assistance with meat fabrication. In addition, I would like to thank Bob Burnett, Emily Helman, Jane Link and Dave Main for their guidance, assistance and clarification concerning lab procedures. Dr. Wes Osburn and Christine Ebeling were essential in the success of the sensory panel analysis. Finally, I would like to thank Stacy Scramlin for her help with assigning marbling scores. The author would like to thank Packerland Packing Company for sponsoring the current project. Specifically, Dr. Rod Bowling and Mr. Tom Reed for their willingness to help in any way possible. Your hard work and input was crucial to the success of this project. Mr. Charley Paulson and the whole crew at Packerland Packing Company, Plainwell, Ml were phenomenal. Their hard work and assistance throughout the duration of this project was impeccable. Finally, I would like to thank my family for their never ending support. To my parents, Temple and Karen, for always believing in me and encouraging me to always strive for excellence. I would also like to thank my sister Kirsten, and brother Temple, for all the advice and encouragement you have provided throughout the years. I will forever be indebted to you all. iv TABLE OF CONTENTS Chapter Page I. INTRODUCTION ................................................................. 1 ll. REVIEW OF LITERATURE ................................................... 5 Holstein Cattle vs. Beef Type Breeds ....................................... 5 Feedlot Perfomance ................................................... 5 Breed/Biological Type ................................................. 7 Palatability ............................................................... 8 Composition ............................................................ 10 Carcass Characteristics ............................................. 15 Yearling vs. Calf-fed Market Animal ....................................... 17 Feedlot Performance ................................................. 17 Breed/Biological Type ................................................ 19 Palatability ............................................................... 21 Composition ............................................................. 21 Carcass Characteristics .............................................. 22 Economics ............................................................... 24 Effects of Anabolic Implants .................................................. 26 Mechanism of Action .................................................. 26 Effects of Anabolic Implants on Feedlot Perfomance ....... 28 Effects of Anabolic Implants on Carcass Characteristics....30 Effects of Anabolic Implants on Palatability of Beef ........... 34 Economic Returns ..................................................... 36 III. FEEDLOT PERFORMANCE, CARCASS AND PALATABILITY TRAITS, AS WELL AS SUBSEQUENT ECONOMIC RELEVANCE IN CALF-F ED AND YEARLING HOLSTEIN AND ANGUS STEERS ........................................................................... 37 Introduction ...................................................................... 37 Materials and Methods ....................................................... 38 Results and Discussion ....................................................... 48 IV. SUMMARY AND CONCLUSIONS ........................................ 72 LITERATURE CITED .................................................................. 78 APPENDIXES ........................................................................... 87 APPENDIX A - Per Capita Consumption and Deflated Prices for Beef, 1960 through 2000 ................................ 87 APPENDIX B - Top Five “Greatest Quality Challenges” Identified by 2000 National Beef Quality Audit ....................... 88 APPENDIX C - Current Branded and Certified Beef Programs.....89 APPENDIX D - Meat Descriptive Attribute Ballot... ...... 91 APPENDIX E - United States ten year price series for corn and soybeans ..................................................... 92 APPENDIX F - Interest rates on agricultural products, 1993-2002 .................................................... 93 APPENDIX G - Components of carcass value .......................... 94 vi LIST OF TABLES Table Page 2.1 — Anabolic implants approved for use in beef cattle ................................ 27 3.1 - Composition of finishing diet fed to steers (DM basis) ............................ 40 3.2 — Feedlot performance for yearlings ..................................................... 50 3.3 — Feedlot performance for calf-feds ..................................................... 51 3.4 — Carcass trait comparisons for yearlings ............................................. 54 3.5 — Carcass trait comparisons for calf-feds .............................................. 55 3.6 - USDA yield grade distribution .......................................................... 56 3.7 - USDA quality grade distribution ........................................................ 56 3.8 - Proximate analysis of longissimus dorsi steaks and L*, a", and b* values for yearlings ......................................................................................... 61 3.9 - Proximate analysis of longissimus dorsi steaks and L*, a*, and b* values for calf-feds .......................................................................................... 62 3.10 - Sensory evaluations and shear force values for longissimus dorsi steaks for yearlings ............................................................................... 65 3.11 - Sensory evaluations and shear force values for longissimus dorsi steaks for calf-feds ................................................................................ 66 3.12 — Economic indicators for feedlot performance and carcass traits for yearlings ................................................................................... 68 3.13 - Economic indicators for feedlot performance and carcass traits for calf-feds ................................................................................... 69 vii LIST OF FIGURES Figure Page 2.1 — Carcass and tissue weights from Hereford and Friesian steers slaughtered at 6-mo intervals ....................................................... 12 viii GLOSSARY ADF - Acid detergent fiber ADG — Average daily gain Ca - Calcium CAB — Certified Angus Beef CALF — Calf-feds COG — Cost of gain CP — Crude protein DMI — Dry matter intake DOF - Days on feed DP - Dressing percent E2 - Estrogen EW — Early weaned, place in feedlot at 3.5 months of age FAST - Fast grown yearlings FE — Feed conversion efficiency HCW — Hot carcass weight lGF-1 — Insulin-like growth factor-1 KPH - Kidney, pelvic and heart fat LD - Longissiumus dorsi LG — Weaned and grazed for 122 (I, placed in feedlot at 17.4 months of age ME — Metabolizable energy MS — Marbling score NBQA - National Beef Quality Audit NDF - Neutral detergent fiber NW — Weaned, placed in feedlot at 7.9 months of age P - Phosphorus QG - Quality grade REA - Ribeye area RLRC - Rib, loin, round and chuck SG — Weaned and grazed for 68 (I, placed in feedlot at 15.4 months of age SLOW -— Slow grown yearlings ST — Somatotropin TBA — Trenbolone acetate TDN - Total digestible nutrients TMR — Total mixed ration USDA — United States Department of Agriculture WBS - Wamer-Bratzler shear force WP - Weaned and pastured on wheat, placed in feedlot at 11.6 months of age YG — Yield grade ix CHAPTER 1 INTRODUCTION During the past 30 years, the US. beef industry has undergone immense changes with respect to almost every aspect of production and marketing. These transformations were driven by Changing consumer preferences and decreased demand for typical commodity beef. Appendix A demonstrates a scatter plot depicting changes in per capita consumption and deflated prices for beef from 1960 through 2000. The negatively sloping demand curve through 1998 is far below the demand curve running through 1980, 1985 or even 1990. Thus, as the demand curve moves down and to the left, there is a decrease in demand. If this pattern continues over time, the result will be loss of market share due to producers exiting the business. That loss is evident as per capita consumption fell from 43 kg in 1976 to 30 kg in 1993. Furthermore, from 1979 through 1998 beef demand consistently declined every year resulting in a 23% decrease in beef consumption (USDA, 1998). Consequently, economic pressures have sparked an evolution in cattle production - from a commodity beef industry to one driven by consumer wants and needs. Under the current industry structure, USDA quality and yield grades are used to separate beef carcasses into groups, exemplifying potential differences in palatability (tenderness, juiciness and flavor) and cutability (% closely-trimmed, retail product). The USDA grading system is designed to assign value to beef carcasses based on characteristics consumers find superior and accounts for traits such as carcass fat content, ribeye area, intramuscular fat, and skeletal and lean maturity. Ideally, the resulting hierarchical groups are composed of carcasses exhibiting similar quality and yield grade factors and thus, comparable dollar value. Although the current USDA grading system attempts to categorize carcasses into value groups, there is currently no universally accepted practice used to sort carcasses based on tenderness. Results from the National Beef Quality Audit - 2000 (NCBA, 2001) are presented in Appendix B. Three of the “Greatest Quality Challenges” identified in the NBQA were lack of uniformity and consistency in cattle, carcasses and cuts; inadequate tenderness of beef, and insufficient marbling. Tenderness is the most quintessential palatability attribute affecting beef products (Savell et al., 1986; Smith et al., 1987). In order to maximize palatability Characteristics and produce a more desirable product, beef industry leadership developed and implemented branded and certified beef programs. In fact, this idea swept the industry and today there are over 48 branded or certified beef programs in operation (Appendix C). These programs group carcasses according to certain specifications in order to provide the beef industry with more predictable beef products. Arguably, the most successful branded beef program is Certified Angus Beef (CAB) due to its’ ability to provide consumers with an enjoyable, predictable eating experience. CAB was created on the premise that Angus genetics offer a consistent, high quality beef product with superior taste. The consumer demand generated by CAB has created a robust market for Angus/black-hided cattle. Holstein steers account for close to 20% of the fed-beef production in the United States (Perry and Fox, 1992). Therefore, it is important to determine the production and economic feasibility of utilizing Holstein cattle in the feedlot industry, as well as establish comparisons in eating quality of beef from Holstein versus beef-breed cattle. A recent trend in the cattle feeding industry is to start Holstein calves on high concentrate diets at 113-159 kg and is referred to as calf- fed finishing. Typical cattle performance from calf-fed Holsteins will generally yield average daily gain (ADG) above 1.36 kg and a feed conversion efficiency of less than 6.5 (Schlegel, 1999). Furthermore, Zeigler and coworkers (1971) found no differences in tenderness between Holstein and Angus steers even though Holstein steers had higher (P<0.01) cutability. These results led the author to believe that Holstein cattle are under-valued for potential feedlot use and consumer acceptability. In the present study, Holstein and Angus steers were evaluated in two production systems (calf-fed or yearling) and an implanted versus non-implanted comparison was performed for calf-fed Holsteins, in order to determine if differences exist relative to breed, age, or implant regime. These results will potentially answer the questions: Are there economic differences in Holstein and Angus cattle relative to feedlot performance, carcass characteristics and palatability? Does production system (i.e. calf-fed versus yearling) impact feedlot performance, carcass traits and eating quality? Are growth-promoting implants warranted in calf-fed Holstein production systems for achieving high performance, acceptable carcass quality and a superior eating experience? CHAPTER 2 REVIEW OF LITERATURE Holstein Cattle vs. Beef Type Breeds Feedlot Performance Because approximately one-fifth of the United States cow herd is made up of dairy cows and 15 to 20% of fed beef steers are Holstein, it is important to investigate comparative value of Holstein and beef type breeds for beef production. Hallman, Jr. (1971) examined the efficacy of raising dairy calves for beef purposes. In this study, 4,448 Holstein calves were placed on test during a 3-year period at three locations. At 14 weeks of age, cattle were sent to feedlots, weighing approximately 117.9 kg. Throughout the feeding period, from 14 weeks of age to a market weight of 453.5 kg, ADG (kg) and feed conversion efficiency (FE, kg consumed per kg of gain) for these cattle were 1.36 and 2.36; 1.26 and 2.93; and 1.17 and 3.40 for top performance, average performance and fair performance groups, respectively. The early literature documents growth and performance advantages for Holstein cattle as compared to British beef breeds. Kidwell and McCormick (1956) found Holstein steers to gain more rapidly and require less grain per kg of gain than Hereford steers. Likewise, in a review of 19 different experiments, Henderson (1969) found Holstein steers to consistently achieve higher ADC and consume more feed, while maintaining similar feed conversion efficiency when compared to beef type steers. Garcia-de-Siles et al. (1977) performed a trial using Holstein and Hereford steers placed on feedlot rations at approximately 270 d of age and fed to two slaughter weight endpoints of 409 and 500 kg. At 280d, 365d, and harvest, weight per day of age was 16%, 18%, and 22% greater (P<0.01) for Holsteins than Herefords, agreeing with results from Martin and Wilson (1974) where weight per day of age for Hereford steers was significantly less (P<0.05). Moreover, feed efficiency from 270 d to harvest was 13% more desirable for Holstein cattle, allowing them to reach slaughter weight at an average of 83.3 d younger than Hereford (P<0.01; Garcia- de-Siles et al., 1977). More recent research concurs with these findings. A comparison of individually fed Angus, Polled Hereford, and Holstein steers (T honney, 1987), revealed increased dry matter intake for Holstein steers as compared to Angus and Polled Hereford steers, although this increase was not significant. Additionally, Holstein steers gained 11% faster (P<0.005) than the average of Angus and Polled Hereford steers, resulting in Holstein steers being more efficient (P<0.025). Holstein steers required 6% and 9% less dry matter per unit of gain than Polled Hereford and Angus steers, respectively. Similarly, Thonney et al. (1981) reported that Holstein steers gained .2 kgld faster and required 1 kg less dry matter per kg of gain than traditional, small frame Angus steers from 400 to 500 kg. In a series of studies conducted at Cornell University where Holstein and British beef breed steers were compared at carcass endpoints between 272.4 to 363.2 kg and carcass quality grades of 60 to 100% USDA Choice (Peny and Fox, 1992), weight, daily gain, days on feed and total weight gain were similar between Holstein and beef breed steers. However, dry matter intake was higher (P< 0.01) and contrary to the previous literature, gain per unit of feed was lower (P< 0.01) for the Holstein steers. In a summary of twenty years of feedlot closeouts from yearling cattle, (Dekalb, 2003), beef steers gained 12.3 % more weight per d and were 11.5 % more efficient than Holsteins. Breed/Biological Type Breeds differ in characteristics, however, the most important differences between genotypes are explained by mature target weight (Kidwell and McCormick, 1956; Thonney et al., 1981). This is true because stage of growth, or harvest weight in relation to mature weight, at which cattle are harvested greatly influences rate and efficiency of gain. As cattle mature, more of their gain is composed of fat and less of muscle. Because protein has lower energy content and muscle tissue contains more water than fat tissue, the energetic cost of muscle deposition is less than that of fat. However, protein has a faster turnover rate than fat so that the energetic cost of accretion favors fat deposition (T honney et al., 1981). But, as cattle approach mature weight, energy required per unit of gain increases. Holstein steers have the potential to reach a larger mature size than most traditional beef breeds. Kidwell and McCormick (1956) concluded that animals of larger mature size (Holstein vs. Hereford) had a longer period of linear post-weaning growth, and a greater rate of gain during this period than animals of a smaller mature size. Additionally, when animals were started at equal initial weights and full fed for a constant time period, Holstein cattle deposited a greater proportion of bone and muscle and a smaller proportion Of fat than Hereford cattle. Similarly, Berg and Butterfield (1968) observed that Hereford steers showed a noticeable tendency to begin the fattening phase at lower muscle plus bone weights than did Friesians. Callow (1961) performed a comparative study with Hereford, Milking Shorthorn and Friesian steers. Friesian steers had less fat and a higher dressing percent than either the Shorthoms or Herefords. Herefords had heavier hide weight than Friesians. Furthermore, F riesian steers had a higher proportion of muscle tissue and bone than the other two breeds. Palatability Sensory attributes determine the consumer acceptability of trimmed beef cuts. Price differentials between quality grades are indicative of the emphasis the beef industry has placed on sensory attributes (Armbruster et al., 1983). Although taste panel tenderness and overall acceptability were related (P<0.05) to the quality grades of 494 steers (Campion et al., 1976), in other studies less than 5% and 7% of the variation in tenderness and overall acceptability, respectively, were explained by quality grade (Crouse et al., 1978). Arrnbruster and others (1983) conducted a trial using Angus and Holstein steers fed either corn grain or corn silage diets and housed inside in individual pens or outside in conventional, partially covered paved lots. The cattle were harvested at one of five weights ranging from 363-544 kg for Angus and from 454-635 kg for Holstein. Roasts from Holstein cattle in the slight to moderately abundant degree of marbling categories had better flavor than those of Angus cattle, however, at marbling scores above moderately abundant, Angus roasts were found to be more flavorful. The latter was possibly due to accumulation of more fat associated with higher marbling scores, however, the magnitude of the difference in flavor is of questionable importance. No differences were found in juiciness between the two breeds of cattle, nor did breed difference impact tenderness. Branaman et al. (1962) found no significant differences for shear force values, sensory panel tenderness ratings, aroma ratings, flavor of fat and texture of lean between beef and dairy-type cattle. The flavor of the lean from beef-type cattle was rated higher for intensity (P<0.01) although scores for desirability were not significantly different. The quantity and quality of juiciness were also superior (P<0.01) for the beef-type cattle. The higher scores for juiciness for the roasts from beef-type cattle are probably a result of a greater amount of marbling, which has been positively correlated with juiciness. In a study comparing meat from Hereford, Milking Shorthorn, and Friesian steers (Callow, 1961), overall palatability was similar. Cole et al. (1964) and Ziegler et al. (1971) Observed more marbling in Herefords than Holsteins at similar weights. Herefords also had higher flavor, juiciness, and overall acceptability scores. In a comparison of Hereford and Holstein steers harvested at two weight end-points, Garcia-de-Siles (1977), reported higher (P<0.01) mean flavor and marbling scores for Herefords. In studies comparing Holstein to Angus, Simmental or Angus crossbred steers, sensory evaluations for rib steaks were acceptable for all cattle, although Holstein steers were more tender (P<0.01) and had a higher overall acceptability (P<0.05) than beef breed steers (Thonney et al., 1991; Perry and Fox, 1992). Judge et al. (1965) found few differences in subjective and objective tests for appearance, palatability and cooking characteristics of Longissimus dorsi steaks of Holstein, Red Dane crossbred, Dual-purpose, Angus l (17 mo of age) and Angus II (14 mo of age). The only differences reported were Angus I having higher (P<0.01) moisture and lower tenderness scores (P<0.01) than Angus ll. Additionally the marbling scores for steaks from Angus I were higher (P<0.05) than scores for steaks from Dual-purpose carcasses. Ramsey and coworkers (1963) looked at the impact of type and breed on production, palatability and composition of cattle, finding no significant differences in shear force values, tenderness, juiciness or flavor in round or loin steaks of British and dairy breeds. However, steaks from Zebu cattle consistently received higher shear values, and lower tenderness, juiciness and flavor values as compared to the other two breeds. Composition Composition is one of the most important carcass characteristics from both a physical and chemical viewpoint. Current pricing mechanisms value dairy-type cattle lower than typical beef-type cattle, because of lower dressing percent, inferior conformation and a lower percentage of valuable cuts from the rib and loin (Dikeman et al., 1977). It is often the theory that beef carcasses with ideal conformation should have a greater proportion of the major cuts (Cole et al., 1964; Dikeman et al., 1977). Berg and Butterfield (1968) serially harvested Holstein and Hereford cattle to compare growth patterns of bovine muscle, fat 10 and bone. Their findings revealed that at any given age, Friesians had greater size, more muscle, more bone but essentially the same amount of fat as Herefords (Figure 2.1). Cole and coworkers (1964) compared carcasses of Angus, Hereford, Brahman, Brahman cross, Santa Gertrudis, Holstein and Jersey cattle. Findings from their study indicated that Angus carcasses had the lowest percent separable muscle, separable bone, moisture, protein, round, loin, chuck, and foreshank, but the highest percent separable fat, ether extract, flank and brisket. Additionally, Holstein carcasses produced the highest percent separable muscle, separable bone, moisture, protein, round, and foreshank; as well as the highest percent separable muscle in all wholesale cuts except the chuck and plate; and highest percent separable bone within all wholesale cuts except the flank. They were also the lowest of all breeds in percent separable fat of the entire side, ether extract content of {he carcass, flank, and separable fat in all but the Chuck. In concurrence with these results, Branaman et al. (1962) found no significant difference in the percent rib, round and loin (high-priced cuts) for Holstein versus beef-type cattle. Additionally, the percent separable lean between the two groups were similar, indicating that both groups contained the same amount of muscle. Although beef-type cattle had a higher percent (approximately 2.3% more) of separable fat, this difference was not significant, while Holstein cattle produced a significantly greater percentage (P<0.05) of separable bone. In a trial comparing dairy and beef carcasses, Judge and coworkers (1965) found the combined round, loin and rib expressed as a percent of carcass weight of steers the same age was higher for Holsteins than Angus 11 l l r l 360 - - Hereford ' Friesian —— — l ' ' c - Carcass Wt. / c - 30° F M - Muscle / - _ F - Fat - _ 3 - Bone ’ 240 - 180 - 120 - WEIGHT OF TISSUE - KG AGE IN MONTHS Figure 2.1. Carcass and tissue weights from Hereford and Friesian steers slaughtered at 6-mo. Intervals. (Adapted from Berg and Butterfield, 1968). (72.1% and 66.1%, P<0.05). However, when dairy carcasses were compared to beef carcasses of younger cattle, no difference was seen. Furthermore, after reviewing available literature, Pearson (1966) concluded that beef and dairy cattle finished under the same conditions differed little in retail cut-out. However, beef cattle tended to have a higher dressing percent, while also producing a greater amount of separable fat. Dikeman and others (1977) conducted a trial using steer carcasses from three major British beef breeds (fifteen in each of two weight groups; light, 227 to 250 kg and heavy, 318 to 340 kg) and Holstein. The heavy British group had less bone (P<0.01) than the Holsteins, but more external and total fat (P<0.01). There were no differences in weight of total retail cuts from the rib, loin, round and chuck (RLRC) or roasts and steaks in the RLRC. However, Holstein carcasses had a higher (P<0.05) proportion of combined four primal cuts from the RLRC and a lower (P<0.01) proportion of flank than the heavy British group. Additionally, light British carcasses had a higher (P<0.01) percentage of retail cuts and RLRC roasts and steaks, less (P<0.01) bone and less (P<0.01) external fat trim from the RLRC than Holstein carcasses. The results from these studies are indicative of the role fat plays in dressing percent, separable muscle, separable bone, protein, and yield of major untrimmed wholesale cuts among breeds. When assigning value to meat animals, the amount of lean is extremely important, however distribution of lean is equally important since large price differentials exist between beef primals. Garcia-de- Siles (1977) reported Hereford cattle to be significantly older (P<0.01) than Holstein steers at harvest, while no breed differences were evident in chilled 13 carcass weight. Consequently, based on days of age, Chilled carcass weight, RLRC, edible portion, and trimmed loin plus round were greater (P<0.01) for Holsteins. In addition, Holstein carcasses had heavier (P<0.01) round and Chuck weights and chuck weight expressed as a percentage of side weight. Untrimmed rib weight and percentage of side weight were greater (P<0.01) in Hereford carcasses than Holsteins. Untrimmed loins were heavier (P<0.05) in Herefords, but no difference was observed in trimmed loin percentage. Hereford cattle had greater longissimus muscle area (P<0.01), whereas, Holstein carcasses had higher percentage cutability (P<0.01). These results indicate a more rapid growth for Holstein cattle, as they reached assigned harvest weight at a younger age. Thonney and others (1984) compared Holstein and Hereford steers harvested at five different weights. At the same carcass weight, Holstein steers had more (P<0.05) trimmed chuck, rib, loin and round primal cuts. It is interesting to note that when carcass weight without the kidney and kidney, pelvic, and heart fat was used as a predictor variable, each kilogram increase in carcass weight contained more of each of the trimmed primal cuts and the differences between Holstein and Angus carcasses were larger. Additionally, the percentage of primal cuts in relation to chilled side weight, declined at a decreasing rate with increasing carcass side weight from 100-200 kg. In summary, when compared at common age or weight endpoints, Holstein carcasses have a higher percentage of muscle and bone, while British breed carcasses have a higher percentage of fat. However, when compared to younger British breed carcasses, Holstein carcasses are similar in composition. 14 This indicates that British cattle are earlier maturing than Holstein cattle and begin depositing fat at earlier ages. Carcass Characteristics Holstein carcasses are valued lower than carcasses from beef breeds and receive discounts in the market place despite their ability to reach the industry standard of USDA Choice quality grade at acceptable carcass weights (Nour et al., 1983a; Knapp et al., 1989) and produce leaner carcasses with as much or more boneless retail yield (Nour et al., 1981, 1983b; Thonney et al., 1984; Knapp et al., 1989). In marketing studies conducted by Hallman, Jr. (1971), Holstein steers graded at least USDA Select, had a minimum dressing percent (DP) of 56 %, and provided cuts acceptable to consumers. Taste panel studies indicated Holstein beef flavor was satisfactory and women actually preferred the flavor of Holstein beef. Cutability studies indicated that Holstein steer carcasses grading USDA Select produced 6 to 8 % more salable beef than USDA Choice carcasses. In the Cornell studies (Perry and Fox, 1992), no differences were seen in hot carcass weight (HCW), marbling scores (MS), quality grade (QG) or yield grade (YG) between Holstein and beef steers. They did, however, document lower conformation scores (P < 0.01), smaller rib eye area (P < 0.05) and increased bone (P < 0.01) for Holstein steers as compared to beef steers. More importantly, carcass fat percentage was not different between Holstein and beef breed steers even though Holstein steers had less trimmable external fat, suggesting that Holstein carcasses had greater seam or kidney, pelvic, and heart 15 (KPH) fat than beef breed steers. Henderson (1969) and Garrett (1971) found Holstein steers to have lower DP than beef type steers. Henderson (1969) also concluded that Holstein cattle yielded a higher percent of their carcass weight in boneless trimmed retail cuts. These results are consistent with less fat cover and larger gastrointestinal tract relative to body weight in Holsteins as compared to beef steers. This same review found Holstein cattle to produce carcasses with carcass grade and marbling scores below that of beef type cattle. A lower conformation score for Holsteins was primarily responsible for the lower grading carcasses. Martin and Wilson (1974), found Hereford steers to have more (P<0.001) fat and larger (P<0.01) longissimus muscle area (REA), however, Holstein cattle were higher in cutability (P<0.01). This corresponds with results from Nour and collaborators (1983a) who reported Angus carcasses to have 7.2 cm2 larger (P<0.005) REA than Holstein carcasses at any chilled carcass weight. Likewise, Knapp et al. (1989) reported numerically larger REA for English breed cattle over Holstein cattle and significantly larger (P<0.05) REA for exotic breed cattle. In addition, Knapp et al. (1989) reported Holstein cattle to have significantly more (P<0.05) KPH, and significantly lower (P<0.05) Y6 and DP than British cattle. In summary, the early literature demonstrated a marked advantage for Holstein steers in growth rate and carcass leanness as compared to beef-type steers. However, the more recent literature where harvest endpoints and feeding conditions were similar suggest growth rates are similar but Holsteins have less subcutaneous fat. 16 Yearling vs. Calf-fed Market Animals Many of today’s cattle, including Holsteins, are faster growing and have a larger mature size than cattle produced ten to twenty years ago. Managing large-framed calves in a traditional grazing system followed by high grain finishing may result in carcasses that are ovenlveight and, therefore, discounted at harvest. To avoid heavy carcasses, large-framed calves are sometimes placed on a high grain diet immediately after weaning. Because these systems offer differing profit potentials and require different management techniques, it is important to choose the strategy most beneficial for each individual group of cattle (Sindt et al., 1991). Feedlot Performance There is some evidence that calf-fed cattle gain more efficiently than yearlings. Compared to yearlings, Hickok et al. (1992), found that calves gained 0.10 kgld less during the finishing period (P<0.05), however, calves required 0.82 kg less total digestible nutrients (T DN) per kg of gain (P<0.05) and the lifetime ADG was greater for the calves (P<0.05). This agrees with Dikeman et al. (1985b) who found that metabolizable energy (ME) intake per kg gain was lower (P<0.05) for cattle on an accelerated feeding system (calf-fed) versus cattle on a conventional feeding system (yearling-fed). Overall ADG was greater (P<0.05) for calf-feds, whereas, ADG during the finishing period was higher for yearling cattle (Dikeman et al., 1985b; Jordan et al., 2002). Additionally, calf-fed steers were found to require less dry matter intake (DMI) per kg gain (P<0.05, Dikeman 17 et al., 1985a; Hill et al., 1993; Jordan et al., 2002). Oklahoma researchers used 140 steers of uniform age in a trial comparing five different management systems 1) early weaned and placed into a feedlot at 3.5 mo. (EVV); 2) weaned and placed in a feedlot at 7.9 mo. (NW); 3) weaned at normal age but grazed wheat pasture for 112 d prior to placing in a feedlot at 11.6 mo. (WP); 4) weaned at normal age but wintered on dry native range for 68 d prior to placement in a feedlot at 15.4 mo. (SG); 5) weaned at normal age, wintered on dry native range and then grazed native range for 122 d prior to placement in a feedlot at 17.4 mo. (LG; Gill et al., 1993a). Cattle were harvested when pen average fat cover reached 1.27 cm. Steers that were backgrounded on wheat or grass pasture (WP, SG, and LG) had greater gains in the feedlot (P<0.02) than cattle entering the feedlot directly after weaning. DMI was lower for calf-fed steers and EW and NW cattle performed much more efficiently (P<0.02) than cattle that were backgrounded before being placed in the feedlot. Age may explain a large portion of these differences in rate and efficiency of gain between calves and yearlings. Yearling cattle generally eat more than calves, which is in part due to greater capacity of the digestive tract. Additionally, as cattle age, hormones change and extent of chewing actually decreases, causing reduced digestibility of feed and reduced energetic efficiency (Gill et al., 1993a). Harris and co-workers (1997) found that calf-fed and yearling-fed cattle fed to a constant age end point of 16 mo. did not differ in ADG. However, when cattle were fed to constant live weight end points, yearling-fed cattle gained more rapidly (P<0.05), partially due to compensatory gain. When calf and yearling-fed cattle were finished to a constant age endpoint, 18 calf-feds had greater carcass weight, longissimus dorsi weight, DP, adjusted fat thickness, KPH, numerical YG, marbling score (MS) and 06 (Harris et al., 1997). Lunt and Orrne (1987) noted that yearling cattle realized compensatory gain during the first month on feed and also gained faster than the weanlings during most of the trial. In a summary of five years of research trials comparing calf and yearling finishing systems, Sindt and others (1991) concluded that calves consumed less feed, gained slower, but required less feed per kg of gain than yearlings. Ridenour et al. (1982) examined feedlot performance and carcass characteristics of 365 crossbred steers assigned to one of five growing programs: 1) high concentrate diet (HC) throughout growing to 273 kg and finishing; 2) 50% concentrate diet to 273 kg and then HC (50c-273); 3) 50% concentrate diet to 364 kg and then HC (SOC-364); 4) irrigated wheat pasture to 273 kg and then HC (WP-273) and 5) irrigated wheat pasture to 364 kg and then HC (WP-364). During the growing phase, steers fed HC had the highest ADG and had the lowest feed to gain ratio, while the 50C-273 and WP—273 cattle gained the fastest (P<0.05) during the finishing period. Overall performance resulted in HC and 50C—273 cattle gaining the fastest (P<0.01) and HC cattle being the most efficient and requiring the least total days on feed (DOF). Breed/Biological Type Dikeman et al. (1985b) conducted a trial to evaluate the effects of two different biological types of cattle in either an accelerated (calf-fed) or traditional (yearling) finishing system. Using Angus x Hereford (A x H) and large type 19 Simmental-sired crossbred (S x C) steers as the two biological types, they concluded that the larger framed cattle tended to gain faster (P>0.05) than the smaller framed steers and metabolizable energy consumption was also higher (P<0.05) for the Simmental-sired cattle. Additionally, A x H cattle in the calf-fed system had higher (P<0.05) dressing percentages than S x C cattle. However, in the yearling system, SxC tended (P<0.10) to have higher dressing percentages than A x H cattle. S x C cattle had less (P<0.05) fat thickness, less (P<0.05) KPH fat, larger (P<0.05) longissimus dorsi area, lower (P<0.05) USDA yield grade values, lower (P<0.05) percentages of carcass soft-tissue water, lower (P<0.05) marbling scores and lower (P<0.05) USDA quality grades than A x H cattle. Longissimus dorsi and semimembranosus steaks were not different in palatability between cattle types, but shear force values were higher for S x C cattle than for A x H. Dikeman and coworkers (1985b) concluded that large- framed Simmental cattle had genetic potential for rapid growth and a high percentage of retail product and are most economical when fed for maximum growth after weaning (calf-fed). However, smaller framed A x H cattle did not have adequate growth rates and produced carcasses with unacceptable carcass weights when finished as calf-feds. In addition, A x H cattle could be economical in a conventional feeding system if harvested at lighter weights to avoid excess carcass fat and obtain more efficient feed utilization. S x C cattle were not economical on the conventional yearling fed system because maintenance feed and nonfeed costs became disproportionately high. 20 Palatability Lunt and Orrne (1987) evaluated Hereford, Angus and Hereford x Angus heifers for feedlot performance and carcass traits when they were finished as either weanling calves or as yearlings. Sensory panel ratings for tenderness were higher (better; P<0.05) for weanlings than for yearlings for both ribeye and inside round steaks, however, no differences were identified for flavor, juiciness or overall palatability of steaks. Dikeman et al. (1985a; 1985b) found few differences in palatability between calf-fed and yearling longissimus muscles, however, sensory evaluations of the semimembranosus revealed less connective tissue, and higher tenderness and juiciness scores for calf-feds (P<0.05). Harris and co-workers (1997) found no palatability differences in calf-fed and yearling steers finished to constant age or live weight endpoints. Composition Lunt and Orrne (1987) found no differences in yield of untrimmed primal cuts or in retail yield of closely trimmed primal cuts between weanling and yearling heifers. This agrees with Ridenour et al. (1982) where separation of the 9-10-11 rib revealed no differences (P>0.05) in percentage lean, fat, and bone between calf-fed and yearling fed steers. Additionally, yield of untrimmed lean cuts was not different (P>0.05), however, weanlings yielded lower percentages of Closely trimmed retail lean cuts than yearlings (Lunt and On'ne, 1987). When fed to lighter harvest weights, calf-fed steers had lighter rib, bone, and soft tissue weights from the 9-10-11 rib section (P<0.05, Dikeman et al., 1985a). 21 Additionally, water and protein percent were higher and ether extract percent was lower for calf-feds than yearlings. Carcass Characteristics Producers and packers claim a smaller percentage of calf-fed cattle grade USDA Choice and are discounted at the harvest facility when compared to yearlings. However, the data from Sindt et al. (1991) suggests that calves fed for 180 to 210 d have the potential to have similar quality grades as yearlings. Carcass Characteristics of calf-fed versus yearling-fed cattle vary depending upon the endpoints used for completion of the feeding period. For calf- and yearling-fed cattle fed to constant weight endpoints, dressing percent was significantly higher (P<0.05) for calf-fed steers on accelerated finishing programs (Dikeman et al., 1985a; Harris et al., 1997). However, Dikeman and coworkers (1985a) lacked a solid explanation for the increased dressing percent, as the yearling-fed cattle produced carcasses with a greater amount of fat (P<0.05). In studies where calf-feds were harvested at lighter weights than yearling-fed steers, the calf-fed steers displayed smaller REA, less actual carcass backfat, and lower numerical YG (P<0.05; Dikeman et al., 1985a,; Dikeman et al., 1985b; Hickok et al., 1992). In addition, Dikeman and others (1985a and 1985b) concluded that calf-feds had significantly lower MS and QG (P<0.05), potentially due to lower fat deposition in the calf-fed cattle. A four year summary of research from the University of Nebraska (Jordan et al., 2002) found similar results. Calf-fed steers had a significantly lower numerical YG (P<0.05), 22 although there were no differences in fat thickness or MS. Gill et al. (1993b) reported lighter carcass weights and lower lean maturity scores for calf-fed versus yearling-fed steers. No significant differences were seen for MS, REA, fat cover, KPH fat, or YG for calf-fed and yearling-fed cattle, although percent grading choice were 80.2, 67.9, 71.4, 89.3, and 74 for EW, NW, WP, SG and LG (acronyms defined on page 18), respectively. Lunt and Orrne (1987) harvested weanling and yearling heifers as their individual weights approached 443 kg. At this weight endpoint, weanlings had more fat thickness over the twetfth rib; more KPH fat; higher numerical (less desirable) YG; more marbling; higher (more desirable) CG and higher DP (P<0.05). Sindt et al. (1991) found that calves had more fat over the 12th rib and had a higher percent of USDA Choice carcasses than yearlings. This may be due to yearlings being harvested too soon. Ridenour et al. (1982) found that calf-fed steers had the highest (P<0.05) dressing percentage and the largest (P<0.05) ribeye area when compared to steers fed lower concentrate or grazing diets during the growing phase. Additionally, steers fed high concentrate or low concentrate diets to 273 kg and then placed on high concentrate diets had the highest (P<0.05) percentage of KPH fat. When fed to a constant age endpoint, calf-fed steers had heavier HCW, higher DP, more fat, larger REA, and more KPH fat; as well as, higher USDA YG, USDA MS, and USDA QG (P<0.05, Harris et al., 1997). In contrast, when cattle were fed to constant live weight endpoints, calf-feds only exhibited higher (P<0.05) dressing percent and USDA yield grade. 23 Economics Harvest breakeven prices and profitability are dependent on several factors such as purchase price, the cost of forage, interest rates, yardage, the price of corn and harvest price. Jordan and coworkers (2002) reported year by treatment interactions (P<0.05) for harvest breakeven and profit/loss in their comparison of calf-fed and yearling-fed systems. Nonetheless, these averages are real with respect to producer profitability. Four year averages of harvest breakevens for fast grown yearlings (FAST), slow grown yearlings (SLOW), and calf-feds (CALF) were $66.00, $69.21, and $68.10 respectively. Because these groups were fed, sold, and harvested at different times, profitability may be a better measure since it accounts for different marketing times. The FAST yearlings were the most profitable group (P<0.05), showing an average profit of $21.00/hd for the four-year period. Losses for the CALF and SLOW systems were -23.18 and -20.66 ($lhd), respectively. Gill and others (1993b) investigated the starting age of cattle on the effects of economics and feedlot carcass characteristics of steers. The economic analysis in that study utilized a 10—year price series to account for yearly variation in price. The calves in this trial were born in the spring, therefore harvest dates were chosen on that basis. Economic outcome may differ if calves had been born during another season. Based on the 10-year average prices used and production costs, early weaned cattle placed in a feedlot at 3.5 mo. of age (EW) were the most profitable to the feeder averaging $143.11/hd. In contrast, cattle weaned at a normal age, wintered on dry native range and then grazed on early intensively managed native range for 24 122 d prior to placement in a feedlot at 17.4 mo. (LG) returned the least - $20.48Ihd. Some of this variation in profit is due to time of harvest, with EW steers being harvested in April when cattle prices normally peak and LG being harvested in July when the fed cattle market is historically low. Additionally, cost of gain (COG) was lowest for early-weaned cattle placed in the feedlot at 3.5 mo of age, while LG had the highest COG (Gill et al., 1993b). Sindt et al. (1991) reported higher yardage, feed and interest costs for calves than yearlings, but lower initial per head cost. Interest cost is a function of initial purchase price, feed cost, and days on feed (DOF), therefore, increased interest cost for calf-feds is due to more DOF and higher feed costs. Additionally, health and death losses were greater for calves than yearlings. Nonetheless, COG was lower for calves than yearlings ($51.59 and $52.481cwt.), due to better feed efficiency and composition of gain. If calves are fed an average of 200 d and yearlings are fed an average of 110 d, then a feedlot can only market one and a half turns of calves per year, whereas they can market three turns of yearlings. This additional turnover of cattle may increase profits for a feedyard due to increased volume (Sindt et al., 1991). Moreover, increased turnover allows feeders to spread their risk over a large number of animals. Dikeman and others (1985b) discovered cattle on accelerated feeding systems had lower total costs and lower cost per kg of retail product when compared to cattle on conventional grazing systems. Additionally, for both breeds used in the trial, economic return was higher for cattle on an accelerated feeding system. 25 Effects of Anabolic Implants Growth-promoting hormones have evolved into one of the best non- nutritional tools available to cattle producers, increasing both biological and economical efficiency (Nichols et al., 2002). Approved for use in 1954, implants are widely used, with over 97% of all cattle entering the feedlot at 318 kg or more being implanted at least once (Duckett and Andrae, 2001). There are currently 36 brand name implants approved for use in beef cattle (FDA, 2003; Table 2.1). These growth-promotants are used in cattle of all ages and can be utilized to increase performance during suckling, growing and finishing phases of production. Because implants are used in multiple production phases, steers and heifers harvested for beef may receive as many as four to six implants in their lifetime (Platter, 2003). The objective of each implant is to increase ADG, improve FE and YG, enhance profit opportunity, and provide a high rate Of return on investment. Mechanism of Action The mode of action of growth hormones on muscle tissue growth, adipose tissue deposition, and skeletal development is not fully understood. Anabolic implants are categorized as being estrogenic, androgenic, or both estrogenic and androgenic in nature, and they work to increase muscle accretion and retard protein degradation (Nichols et al., 2002; Webb et al., 2002). Somatotropin (ST, i.e. growth hormone), which is regulated by steroids, is thought to be the main determinant of muscle accretion in cattle (Webb et al., 2002). 26 Table 2.1. Anabolic implants approved for use in beef cattle Trade Name Hormone Content Manufacturer Ralgro Synovex C; Component E-C; Component E-C with Tylan Revalor G; Component TE-G; Component TE-G with Tylan Synovex S; Component E-S; Component E-S with Tylan Synovex H; Component E-H; Component E-H with Tylan Revalor H; Component TE-H; Component TE-H with Tylan Revalor IH; Component TE-IH Ralgro Magnum Synovex Plus Finaplix S; Component T-S; Component T-S with Tylan Finaplix H; Component T-H; Component T-H with Tylan Revalor 8; Component TE-S; Component TE-S with Tylan Compudose Encore Synovex Choice Revalor IS; Component TE-IS Revalor 200; Component TE- 200 Zeranol: 36 mg Progesterone:100 mg; E2 benzoate‘: 10 mg Progesterone:100 mg; 10 mg; tylosin TBA3: 40 mg; 52-1732: 8 mg TBA: 40 mg; E2-17B: 8 mg; tylosin Progesterone: 200 mg; 20 mg Progesterone: 200 mg; 20 mg; tylosin Testosterone: 200 mg; 20 mg Testosterone: 200 mg; 20 mg; tylosin TBA: 140 mg; Ez-17B: 14 mg TBA: 140 mg; E2-17B: 14 mg; tylosin TBA: 80 mg; E2-17B: 8 mg Zeranol: 72 mg TBA: 200 mg; E2 benzoate: 28 mg TBA: 140 mg TBA: 140 mg; tylosin TBA: 200 mg TBA: 200 mg; tylosin TBA: 120 mg; E2-17B: 24 mg TBA: 120 mg; E2-17B: 24 mg; tylosin E2-17B: 25.7 mg 52-17B: 43.9 mg TBA: 100 mg; E2 benzoate: 14 mg TBA: 80 mg; E2-17B: 16 mg TBA: 200 mg; E2-17B: 20 mg E2 benzoate: E2 benzoate: E2 benzoate: E2 benzoate: E2 benzoate: Schering-Plough Ft. Dodge; Ivy; Ivy Hoechst Roussel Ivy; Ivy Ft. Dodge; Ivy; Ivy Ft. Dodge; Ivy; Ivy Hoechst Roussel; Ivy; Ivy Hoechst Roussel; Ivy Schering-Plough Ft Dodge Hoechst Roussel; Ivy; Ivy chhst Roussel; Ivy; Ivy Hoechst Roussel; Ivy; Ivy Ivy IVY Ft. Dodge Hoechst Roussel; Ivy Hoechst Roussel; Ivy 1Estradiol benzoate is approximately 72% the estrogenic activity of Estradiol-17B (E2-17B) 2Estradiol 1 7-B 3Trenbolone acetate Source: (FDA; November, 2003) 27 Estrogenic and estrogen-like implants increase the Circulating levels of ST, secreted from the anterior pituitary, and insulin-like growth factor-1 (IGF-1), secreted from the liver in response to ST, which is thought to increase protein deposition (Apple et al., 1991; Webb et al., 2002). Additionally, researchers have detected high-affinity estrogen receptors in bovine skeletal muscle which offers a new possible mode of action of estrogen and estrogen-like compounds (Webb et al., 2002). Androgens have been shown to increase carcass protein content of cattle by stimulation of muscle protein synthesis. However, trenbolone acetate (TBA), a synthetic androgen has been reported to decrease the rate of synthesis and degradation of protein, with the rate of degradation reduced more than synthesis, thus increasing net muscle protein deposition (Apple et al., 1991). Effects of Anabolic Implants on Feedlot Performance Implants have been readily adopted in most production programs to increase growth. In order for growth-promoting implants to positively influence feed efficiency and gain, cattle must have adequate nutrition. Perry et al. (1991a, 1991b), examined the use of TBA and estrogen (E2) in combination with Holstein, Angus and Angus x Simmental steer calves. In their trial, implanted Holstein and Angus steers had greater harvest and carcass weights (P<0.05 and P<0.01, respectively) than non-implanted steers. The number of d required to grade USDA Choice was reduced (P<0.01) with Revalor® (T BAIEz) as compared to controls, and daily gains increased (P<0.01) 17, 26, and 21% in Holstein, Angus and crossbred steers, respectively. Additionally, implanted cattle required less 28 (P<0.01) feed per unit of gain than non-implanted. Fox and coworkers (1989) studied the effect of an initial Ralgro® implant followed by a Revalor® implant on Holstein and beef steer performance and carcass quality. The Ralgro® implant increased daily gain by 9% and feed efficiency by 8.1% and the Revalor® implant increased daily gain 18.5% and feed efficiency 11.0%. Additionally, another trial by the same author, (Fox et al., 1989) where steers received only one Revalor® implant resulted in increased daily gains of 16.7, 26.1, and 21.3 percent in Holstein, Angus and Angus x Simmental calves respectively. Harvest weights needed for cattle to reach USDA Choice marbling were increased (P<0.01) in the Holstein and Angus steers that received implants. In a review of 37 research trials, Duckett and coworkers (1996) found that implanted steers had 18% greater ADC and 6% greater feed intake than non-implanted steers. This translated into implanted steers requiring 8% less feed per kilogram of gain. These findings concur with data compiled in a later review by Duckett and Andrae (2001) who reported implants increase ADG from 16-20% and reduce feed needed per kg of gain by 6-13.5%. Furthermore, Gerken and others (1995) studied the effects of estrogenic and androgenic implants in genetically cloned steers, comparing a control (no implant) with cattle implanted with a single estrogenic implant (Synovex-S®), with a single androgenic implant (Finaplix-S®), or with a single combination implant (Revalor-S®). Results from this study showed implanted steers gained weight more rapidly (P<0.05) and efficiently (P<0.05) than control steers, although no significant differences were evident among the different implant groups. There was a trend, however, for steers 29 implanted with Revalor-S® (combination estrogenic and androgenic) to show the greatest percentage improvement in both ADG and gain to feed ratio when compared to the control. Similarly, Johnson et al. (1996) detected a 16% increase (P<0.001) in ADG throughout the feeding period for implanted steers and feed efficiency was improved 13% from d 0 to 40 (P<.01) and from d 41 to 115 (P=0.07). In conclusion, current research clearly supports claims that hormone implants enhance feedlot performance through increased ADG and improved feed conversion. Efl'ects of Anabolic Implants on Carcass Characteristics Anabolic implants are used routinely in the finishing phase of beef production to improve gains and feed efficiency despite concerns about negative impact of implants on marbling and quality grades of beef carcasses (Duckett et al., 1999). Implants have been shown to increase the incidence of carcass quality defects (dark cutters, reduced tenderness, less marbling; Grandin, 1992), however, implants have also been shown to be beneficial (Webb et al., 2002). Gardner and others (1995) compared implanted Holstein calf-feds, implanted Holstein yearlings, and aggressively implanted calf-fed Holsteins to control (non- implanted) steers. Carcass weight increased (P<0.01) 5% and REA increased 4% for implanted steers over non-implanted steers, while DP, fat thickness, KPH fat, YG, MS, and 06 were not different for implanted versus control steers. It should be noted that aggressively implanted, calf-fed Holstein steers tended to be the most advanced in maturity and have the least marbling, whereas 30 Tym'.“ carcasses from implanted, calf-fed Holsteins tended to have the most marbling, smallest ribeyes, highest numerical yield grades, and the most trimmable fat when compared to aggressively implanted calf-feds or implanted yearling Holsteins. Roeber and others (2000) reported carcasses from non-implanted cattle had smaller longissimus muscle areas (P<0.05) than carcasses from cattle implanted with Encore® & Component® (TBA/E2) alone, Ralgro® (Zeranol) followed by Synovex-Plus® (T BA/Ez), or Revalor-S® (T BAIEz). Hot carcass weight was higher (P<0.05) for implanted cattle versus non-implanted cattle, while external fat thickness or YG were similar. Carcasses for all implanted groups except cattle that received a terminal Synovex-Plus® had higher (P<0.05) skeletal maturity scores than non-implanted steer carcasses, however, lean maturity was similar. Control carcasses had higher (P<0.05) MS and USDA QG than implanted steers except for those steers implanted with Ralgro® followed by Revalor-S® or steers implanted with Encore® or Component® as the intial implant. Likewise, Al-Maamari et al. (1995) reported carcasses from implanted steers had heavier weights, more advanced skeletal maturity, and larger REA than carcasses from non-implanted steers. Steers implanted with estradiol benzoate plus trenbolone acetate on d 0 and 61 had lower (P<0.05) marbling scores than controls. It should be noted that implants are suspected to increase the occurrence of dark cutters, however reports are varied. Several studies have shown that aggressive implant programs increase the incidence of dark cutters (Gardner et al, 1995; Scanga et al., 1998; Webb et al., 2002). Conversely, Gerken et al. 31 (1995) and Roeber et al. (2000) saw no increase in “dark cutting” due to implant treatments. Some define production efficiency as the return of saleable product per unit of feed input; however, the composition of the product needs be considered as it is an important factor in determining the product unit value and cost (Nichols et al., 2002). Rate of empty body fat gain has generally not been influenced by anabolic implants, however rate of empty body protein gain has been markedly increased for implanted compared with non-implanted steers harvested at time- or body weight-constant endpoints (Montgomery et al., 2001). Steers implanted with Synovex-Plus® initially, Synovex-Plus® on d 0 and 61, or Synovex-S® on d O and Synovex-Plus® on d 61 (Duckett et al., 1999) had lower (P<0.05) fatty acid content of the longissimus than controls. Perry and coworkers (1991a) found that cattle implanted with Revalor® had similar percentage of carcass fat and protein. The implant did, however, increase final amount of empty body protein (P<0.01) in Holstein and Angus steers. Additionally, daily empty body protein gain was increased (P<0.01) in all breeds and daily fat gain was increased (P<0.05) in Angus and Simmental crossbred steers. Implantation with Revalor® increased (P<0.05) top butt yield, although it did not alter percentages of other cuts. Perry et al. (1991b) found steers implanted with Ralgro® followed by Revalor® had higher (P<0.05) carcass percentages of chuck, rib eye, top butt, and gooseneck, while cattle implanted with Revalor® only had similar percent wholesale boneless cut yields. Al-Maamari and others (1995) evaluated boxed beef yields for non-implanted (control) steers, steers implanted with estradiol 32 benzoate and trenbolone acetate (ET) on d O and 61, or with estradiol benzoate plus progesterone on d 1 and ET on d 61. Additionally, they evaluated differences in boxed beef yield based on four different endpoints (constant time on feed, constant harvest weight, constant fat thickness, and constant marbling score) and three different trim levels (0 cm, .635 cm, and 2.54 cm). At the constant time on feed endpoint, carcasses from implanted steers produced more total kilograms of major and minor subprimals, lean trim, total boxed beef and bone at all three levels of trimmmable fat. In addition, there were no differences detected among implant treatment groups for weights of trimmable fat, indicating that implants do not alter the amount of fat gain. Implants did increase weight of salable lean while not increasing trimmable fat. When comparisons were made at a constant harvest weight, carcasses from steers implanted twice with ET yielded more (P<0.05) total kilograms of major subprimals and boxed beef than carcasses from non-implanted steers, however, no differences in boxed beef yield or amount of major subprimals was detected for other implant groups. Carcasses from implanted steers yielded fewer (P<0.05) total kilograms of fat than control carcasses at all trim levels. Yields of minor subprimals, lean trim, and bone were not affected by implant treatment when compared to controls. Comparison at a weight-constant endpoint should amplify tissue developmental differences due to implant treatment. When constant fat thickness was used as an endpoint, developmental patterns independent of stage of fattening are contrasted. With this comparison, carcasses from implanted steers yield more (P<0.05) boxed beef at all trim levels as well as more bone than carcasses from 33 non-implanted steers, and as expected no differences (P>0.05) were reported in trimmable fat between treatment groups. Because marbling is often used as a bench-mark or goal for those in the beef cattle industry, constant marbling endpoint reflects an economically important comparison. The results at this endpoint were similar to those detected at the constant fat thickness endpoint with the exception that carcasses from implanted steers yielded significantly more kg (P<0.05) trimmable fat at all three trim levels than carcasses from steers that had not been implanted (AI-Maamari et al., 1995). This increased fat trim indicates that implanted steers required additional fat cover to reach a Small50 degree of marbling when compared to non-implanted steers. Based on the literature, a strong argument can be made for growth promoting implants ability to increase REA and HCW, while reports on other carcass characteristics (marbling, skeletal maturity, YG, QG, KPH fat, and fat thickness) are more variable. In addition, implants do impact composition of beef cattle carcasses, with the main impact reflected in increased protein yield. However, it should be noted that endpoint used can impact carcass composition significantly, especially with respect to trimmable fat. Effects of Anabolic Implants on Palatability of Beef Research suggests that the use of implants may be detrimental to beef carcass tenderness (Roeber et al., 2000; Platter, 2003). Meat science researchers typically measure beef tenderness using Warner-Bratzler shear force (WBS) or by sensory evaluation of tenderness. In a review of 19 studies 34 comparing WBS for implanted and non-implanted cattle, three studies found a significant detrimental effect of one or more implant strategies on WBS and two studies reported implanted cattle were more tender (Nichols et. al, 2002). Moreover, when tenderness was measured with a sensory taste panel, three of thirteen sensory panels found steroid implants to decrease the tenderness of steaks from impanted cattle in comparison to non-implanted cattle. Samber and others (1996) conducted a trial comparing seven implant treatments consisting of combinations of Ralgro® (Zeranol), Synovex-S® (Progesterone/E2), and Revalor-S® (TBA/E2) on beef quality traits of crossbred steers. Steers implanted with TBA IE2 as the initial and terminal implant (2X), or as the initial, intermediate, and terminal implant (3X) had higher WBS scores (P< 0.05) than steers that received no implant. The research by Gerken and co-workers (1995) evaluated strip loin, top sirloin and top round steaks for WBS and sensory panel tenderness. Implant treatment was a significant source of variation in tenderness, but only for the top sirloin steaks. Steers implanted with Synovex- S® were less tender (P<0.05) than control or Finaplix-S® implanted steers, and steers implanted with Revalor-S® did not differ (P>0.05) from the other implant groups or control. Additionally, implant treatment did not (P>0.05) affect sensory panel tenderness ratings of strip loin or top round steaks or shear force values of strip loin, top sirloin, or top round steaks. Thus, this study showed implant treatment had negligible effects on beef tenderness. Likewise, Roeber and others (2000) found only one treatment group (initial implant of Revalor-S® followed by no implant) to be tougher (P<0.05) than steaks from control 35 carcasses based on WBS. On the other hand, in a consumer sensory panel, consumers rated steaks from non-implanted steers as more tender (P<0.05) than steaks from eight treatment groups (Roeber et al., 2000). Economic Returns Because implants improve performance of cattle and increase live weights, there are economic incentives for producers to use them. In a review by Duckett and colleagues ( 1996), they concluded implanting provides an average return on investment of $18.32 on a live basis due to increases in ADG and FE. On a grade and yield basis, the net return on investment was $13.53 per implant investment due to increases in FE and HCW minus decreases in percent Choice carcasses. Additionally, implant strategies for the entire beef production cycle, increased value of the animal $16.32, $25.20, $51.34, and $92.86 for suckling, stocker, feedlot and all phases, respectively (Duckett and Andrae, 2001 ). 36 CHAPTER 3 Feedlot performance, carcass and palatability traits, as well as subsequent economic relevance in calf-fed and yearling Holstein and Angus steers INTRODUCTION Changes in the beef industry are a reflection of changing consumer preferences. Because of the changing consumer, producers have been forced to evaluate alternate production and marketing systems in order to achieve the highest possible returns. Economic pressures have sparked an evolution in cattle production - from a commodity beef industry to one driven by consumer wants and needs. I The current USDA grading system attempts to categorize carcasses into value groups. However, at present, there is no universally accepted practice used to sort carcasses based on tenderness. The three “Greatest Quality Challenges” identified in the 2000 National Beef Quality Audit were lack of uniformity and consistency in cattle, carcasses and cuts, inadequate tenderness of beef, and insufficient marbling (NCBA, 2001). In order to produce a more consistent, desirable product, beef industry leadership developed and implemented branded and certified beef programs. With over 48 programs in place today, perhaps the most successful branded beef program is Certified Angus Beef (CAB). Based on the premise that Angus genetics offer a consistent, high quality beef product with superior taste, the implementation of CAB has created incomparable demand for Angus/black-hided cattle. 37 Close to 20% of the fed-beef production in the United States (Perry and Fox, 1992) is comprised of Holstein steers. It is important to determine the production and economic feasibility of utilizing Holstein cattle in the feedlot, as well as establish comparisons in eating quality of Holstein versus beef breeds. Many cattle feeders today start Holstein calves on high concentrate diets at 114 to 160 kg (calf-fed finishing). Typically calf-fed Holsteins will yield average daily gains (ADG) above 1.3 kg and a feed conversion efficiency of less than 6.5 (Schlegel, 1999). Furthermore, Zeigler and coworkers (1971) found no differences in tenderness between Holstein and Angus steers even though Holstein steers had higher (P<0.01) cutability. These results led the authors to believe that Holstein cattle are under-valued for potential feedlot use and consumer acceptability. The current study evaluated, Holstein and Angus steers in two production systems (calf-fed or yearling) with an implanted versus non- implanted comparison among the calf-fed Holsteins. The Objective of this study was to determine if Holstein production systems can be as profitable as systems with beef breeds (Angus) and whether the eating quality is similar between breeds. MATERIALS AND METHODS Experimental procedures for this study were approved by the Michigan State University Animal Use and Care Committee (AUF #01l02-005-00). A feeding trial was conducted with implanted Holstein calf-feds (IHC; n=70), non- implanted Holstein calf-feds (NHC; n=70), Angus/black calf-feds (BC; n=70), 38 Holstein yearlings (HY; n=90), and Angus/black yearlings (BY; n=110) to determine feedlot performance, carcass traits and palatability differences due to breed and age. Initial weight of steers was 173, 173, 257, 364, and 435 kg, for the IHC, NHC, BC, HY and BY cattle, respectively. After arrival at Michigan State University Beef Cattle Teaching and Research Center, the steers received a routine vaccination program (IBR, Pl3, BVD, BRSV and 7-way Clostridium), lvomec®, ear tag for individual identification and an initial implant. Implant regime for the steers consisted of a Ralgro implant at d 1 for all treatment groups and d 112 for IHC. Steers were reimplanted with Synovex-S at d 196 for the IHC and d 84 for the remaining three implant groups (BC, HY, and BY). NHC did not receive an implant and served as the negative control. The calf-fed steers arrived at the feedlot during the week of January 16, 2002 and were allocated to pens based on weight after a two-week adaptation period, so that pens were comprised of cattle of similar size. The Holstein and Angus/black yearling cattle were started on feed on May 28, 2002 and September 6, 2002 respectively with a three-week adaptation period. Upon trial initiation, steers were fed an 85% concentrate diet (Table 3.1). Steers had free access to water and were fed once daily. At the end of each 28 d period, excess feed remaining in feed bunks was removed and weighed to allow calculation of average pen dry matter intake. Feedlot performance information was monitored at 28 d intervals and endpoints were based on subcutaneous fat thickness, measured via ultrasound attenuation. Harvest endpoints were assigned to achieve industry targets for each breed type and included subcutaneous fat thickness endpoints of 0.762 and 39 Table 3.1. Composition of finishing diet fed to steers (DM basis) Ingredient Diet High moisture corn, % 35 Dry corn, % 40 Corn silage, % 15 Soybean meal, % 5 Supplement, % 5 Chemical component CP, % 13.50 NDF, % 12.64 ADF, % 5.25 Starch, % 61.89 Ca, % 0.67 P, % 0.28 40 1.016 cm for Holstein and 1.016 and 1.27 cm for Angus. As the cattle reached their specific endpoints, they were shipped to Murco Foods Inc. in Plainwell, MI. Post-harvest, quality grade, yield grade, ribeye area, fat thickness at the 12th rib and hot carcass weight were collected. Carcasses were fabricated into subprimals and longissimus dorsi sections from posterior end of the ribeye roll (IMPS #112) were removed for sensory, tenderness, and proximate analysis. Longissimus dorsi sections were transported to the Michigan State University meat laboratory where they were allowed to age for 14 d at 2-4°C (Smith et al., 1978). After aging, a 0.635 cm slice was removed from the posterior end of each rib section and the excess longissimus muscle was diced for use in proximate analysis. The freshly cut rib sections were exposed to oxygen for over 30 minutes to allow for color development, and marbling scores were determined and recorded by two trained evaluators. Additionally, L*, a*, and b* values were measured using the Hunter MiniScan XE (Restin, VA). The Hunter MiniScan XE has a 25 mm—diameter measuring area and a 10° standard observer. The instrument was set to 065 illuminant and CIE L*, a* and b* values were recorded for each rib section. Calibration of the machine was performed each day by measuring against the black and white calibration tiles. After marbling and color evaluations were made, rib sections were vacuum packaged and stored at -28°C until rib sections from all animals in the study were collected. Upon completion of the feeding trial, rib sections from each treatment group were randomly selected from the freezer and 2.54 cm steaks were cut from each longissimus dorsi section for use in sensory evaluation and Wamer-Bratzler shear force 41 determination. Sufficient steaks were prepared to allow two blocks of sensory panel and shear force evaluation. Treatment groups were represented on each day of sensory or shear force evaluation. Trained Sensory Panel Evaluation A trained sensory panel was utilized to determine specific sensory attributes of each ribeye. The sensory panel was trained according to AMSA (1995) and Meilgaard et al. (1991) and included 6 panelists. Each ribeye steak was evaluated using an 8 point hedonic scale, for juiciness (1=extremely dry and =extremely juicy), tenderness (1=extremely tough and 8=extremely tender), and connective tissue (1=abundance of connective tissue and 8=no connective tissue). An example of the trained sensory ballot is found in Appendix D. Frozen steaks were thawed for 24 h at 26°C. Steaks were cooked on a Taylor clamshell grill (model 0824 Taylor Co; Rockton, IL). The upper plate was set to 104.4°C and the bottom plate was set to 102.8°C with a 2.16 cm gap between plates. Steaks were cooked individually and copper constantan thermocouples (0.051 cm diameter, 15.2 cm length; Omega Engineering Inc; Stamford, CT) were inserted into the steak to monitor temperature increase during cooking. Steaks were cooked to a final internal temperature of 70°C +/- 1.5°C and then placed in a two quart bowl Pyrex®. The bowl was placed in an insulated cooler containing previously dampened and heated cloth towels. One towel was placed at the bottom of the cooler and the other was wrapped around the bowl. Prior to sensory determination, the Pyrex® bowl was placed on a 42 Pyrex® double broiler with water maintained at 140°C for sample holding. Sample preparation included cutting 1.27 x 1.27 x 2.54 cm samples from the center portion of each steak. To minimize positional bias, the order of sample preparation was randomized within each session (Meilgaard et al., 1991 ). Testing took place in a climate controlled, partitioned booths equipped with a cool incandescent light. Two cubes were placed in a plastic souffle cup and delivered to each panelist. Panelists were instructed to handle sample cubes with supplied wooden toothpicks. Samples were evaluated for juiciness, muscle fiber tenderness, overall tenderness, and amount of connective tissue. Expectorant cups were provided to prevent taste fatigue as the panelists were instructed not to swallow the samples. Distilled, deionized water was used to Clean the palate between samples. Twenty-five d of testing occurred and each day was divided into 2 sessions with 8 samples evaluated per session. The panelists were standardized for each session by evaluation of 1 warm-up sample and discussion of the results. There was 5 min between each sample and a 15 min break between sessions. The serving order was randomized by treatment and replication. Wamer-Bratzler Shear Force Evaluation Frozen steaks were prepared by the same procedures as for sensory panel evaluation, except that pre- and post-cooking weights were recorded for each steak to determine cooking loss. After cooking, steaks were placed on 43 trays, covered with saran wrap and placed in a cooler (26°C) overnight (Savell et al., 1994). Six 1.27 cm diameter cores were removed from each steak parallel to the longitudinal orientation of the muscle fibers. Each core was sheared on the TAHDi texture analyzer (Texture Technologies Corp, Scarsdale, NY) using a Wamer-Bratzler shear force attachment with a crosshead speed of 20 cmlmin. Proximate Analysis of Meat Samples Each meat sample was sectioned into small (<1 cm squares) pieces, placed in labeled whirl pack bags and frozen until longissimus dorsi samples were collected from all cattle. After all cattle were harvested and every longissimus dorsi sample was collected, samples were ground using Tekmar grinders (T ekmar Co, Cincinnati, OH). Enough sample was added to fill half of the grinding chamber and dry ice was then added to fill the chamber. Each sample was ground for approximately 3 min or until sample was ground into a fine powder. Occasionally, it was necessary to stop in the middle of grinding and stir the sample. The finely ground powder was transferred to labeled whirl pack bags and placed in a freezer to prevent melting. Whirl pack bags were loosely closed to allow the dry ice to evaporate and dissipate. To determine percent moisture content, 2 g (1.03 9) samples were weighed into a filter paper thimble and placed in a drying oven set at 100°C for 20-24 h. After drying, samples were placed in a dessicator to cool and then weighed to determine final weight. The same samples used for moisture determination were also used for fat analysis using soxhlet ether extraction (AOAC section 983.18 Meat and Meat Products, 2000). Samples were placed in extraction apparatus and extracted with petroleum ether for 24 h. Following extraction, samples were briefly placed in a drying oven, allowed to cool in a dessicator and weighed to determine amount Of fat lost during extraction. Protein content of meat samples was determined using the Leco Protein Analyzer (Nitrogen Analyzer Model FP-2000, Leco Corportion, St. Joseph, MI) which uses total combustion to determine N content (AOAC section 983.18 Meat and Meat Products, 2000). Feed Analysis Samples were taken on a monthly basis of the total mixed ration (TMR) and finely ground for use in all feed evaluation assays. ADF and NDF content of feedstuffs were determined using the ANKOMZOO’220 FIBER ANALYZER (ANKOM Technology, Macedon, NY) with procedures specified by ANKOM TECHNOLOGY (1998). Protein content of the TMR samples was determined by analysis of N by total combustion (Nitrogen Analyzer Model FP-2000, Leco Corporation, St. Joseph, MI). Starch content of feedsth was determined through gelatinization and hydrolysis of the samples followed by glucose quantification by high performance liquid chromatography (Casterline et al., 1999) Feedstuffs were also evaluated for calcium and phosphorus concentrations. To prepare samples for these assays, 0.40 :I: 0.10 g of dry 45 material were weighed into HP SOD-plus vessels. Ten ml of concentrated nitric acid was added to each sample, and samples were allowed to digest at room temperature in a hood for one h. Following digestion, samples were further digested in a microwave (MARS 5 Microwave, CEM Corporation). Samples used for calcium analysis were diluted with lanthanum chloride and analyzed with atomic absorption spectroscopy (Unicam 989 Atomic Absorption Spectrometer, Cambridge, United Kingdom). Phosphorus concentration of feed samples was determined by measuring the phosphate ion concentration spectrophotometrically by the procedures of Gomori (1942). Economic Analysis Cost of gain (COG) was determined by summation of feed, yardage, feed interest, cattle interest, medicine and death loss costs. COG was calculated for a ten year time period where feed cost was determined using a ten year price series for corn and soybean meal (USDA, 2003, Appendix E) and yardage was increased $0.01/yr with a starting charge of $0.25lhd/d and an ending charge of $0.34/hdld. A ten year series of interest rates was used to determine interest on cattle and feed (USDA, 2003, Appendix F). Interest on cattle was calculated by multiplying the initial purchase price of the cattle times the proportion a year the cattle were on feed times yearly interest rate. Interest on feed was calculated by taking half of the total feed cost times the proportion of the year the cattle were on feed times the yearly interest rate. Medicine cost included all vaccines, implant, eartag, and medication costs incurred during the feeding period. Death 46 loss cost was calculated by taking the percent death loss for each pen and multiplying it by the initial purchase price of the cattle. Carcass value was determined for HY2, BY2, NHC2, IHC2, and BC2 using data collected from total carcass cutouts conducted in the harvest facility. Based on a ten year price series for beef carcass subprimals (LMIC, 2003), subprimal weights for each group were multiplied by the subprimal price to get the value of each subprimal. Subprimal values with daily or weekly quotes by USDA were pooled to obtain a total carcass value (Value1). In addition, a second carcass value (Value2) was calculated using the same subprimals and ten year price series used in Value1 plus additional carcass subprimals with prices obtained from a harvest facility representative (Appendix G). Gross margin was calculated for HY2, BY2, NHC2, IHC2, and BC2 for both Value1 and Value2. COG was multiplied by the average gain for each group and this total cost was subtracted from the carcass value. Breakeven feeder calf price was calculated for HY2, BY2, NHC2, IHC2, and BC2. This calculation involved dividing initial body weight of each group by the gross margin for Value2. Statistical Analysis Analysis of data was performed using the mixed procedure of SAS (Version 8.1, SAS Institute, Cary, NC). Feedlot performance was analyzed as a two factor design with pens within treatment as a random variable. Design structure for the WBS was a completely randomized design. Final temperature was used as a covariate to account for differences in degree of doneness .47 between steaks. Design structure for carcass and meat traits was a completely randomized design. Sensory panel evaluations were analyzed using a block design with multiple replications (dates) per block (panelist). Means were separated using least squares means with a set at the 0.05 level of significance. RESULTS AND DISCUSSION Steer Performance Table 3.2 and Table 3.3 display feedlot performance differences for yearlings and calf-feds, respectively. Groups will be referred to as Holstein yearling, 0.762 cm (HY1); Holstein yearling, 1.016 cm (HY2); Angus yearling, 1.016 cm (BY1); Angus yearling, 1.27 cm (BY2); non-implanted Holstein calf-fed, 0.762 cm (NHC1); non-implanted Holstein calf-fed, 1.016 cm (NHCZ); implanted Holstein calf-fed, 0.762 cm (IHC1); implanted Holstein calf-fed, 1.016 cm (IHC2); implanted Angus calf-fed, 1.016 cm (BC1); and implanted Angus calf-fed, 1.27 cm (BCZ). Angus cattle required significantly fewer (P<0.01) DOF than Holstein cattle, and similarly cattle harvested at the first fat thickness endpoint required less (P<0.01) DOF. In addition, there was a significant breed by fat thickness endpoint interaction for DOF for both yearlings and calf-feds. For yearling cattle, Holstein steers had higher (P<0.01) final body weight. ADG was higher for Holstein cattle from d 29-56 (P<0.01), d 0-56 (P=0.03), and d 84 through the end of the feeding period (P<0.01), where there was also a significant interaction. Overall ADG was also higher (P<0.01) for cattle harvested at the first fat 48 thickness endpoint. DMI was 7.2% greater (P<0.01) for Holstein yearlings versus Angus yearlings. Overall, Angus yearlings displayed more efficient (P<0.01) feed conversion, and yearlings harvested at the first fat thickness endpoint were more efficient (P=0.02) than those harvested at the second endpoint. Although much of the literature shows Holstein cattle to have increased ADG over British breed cattle (Kidwell and McCormick, 1956; Henderson, 1969; Thonney, 1981; and Thonney, 1987), the current research demonstrates similar gains over the entire feeding period. However, the comparisons in this study used a fat constant endpoint whereas other studies used weight constant or time constant endpoints. As animals were fed for longer amounts of time and more fat was deposited, they gained at a slower rate. Increasing DOF has been shown to reduce ADG and feed efficiency (Van Koevering et al., 1995; Rossi et al., 2001). The inverse relationship between ADG and DOF can be explained by hormone Changes which alter body composition (Gill et al., 1993a; Klopfenstein et al., 1999). As cattle are fed for longer periods of time, they begin to deposit fat at a higher rate than protein (NRC, 1996; Klopfenstein et al., 1999). Furthermore, as cattle age they tend to decrease extent of chewing, which reduces digestibility of feed and energetic efficiency (Gill et al., 1993a). DMI by the Holstein cattle was greater (P<0.01) which agrees with previous research (Kidwell and McCormick, 1956; Henderson, 1969; Thonney, 1981; and Thonney, 1987) where Holstein steers consumed more than British breed steers. Holstein steers were 10.3% less efficient than the Angus steers. 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O0... 00.0 .00v 00.0 00.00 0.0.0 e0.000 0.000 m.0000 .000 .0000 .0... 0.0.0; 000... 00.0 00.0 .00v 00.0. 0.000 00.000 0.00. .0. .0. 0.00. .000. .0... E00; .00.... .00v .00. .00. .00. 0.00. .000 m.000 .000 m.000 000. S 0000 0.00.00 2“. 00 .200 000 .00 0O; .0... 0012 .012 0000 8.000.000 .000___0009n. 0.00.-0.00 .o. cocmELotoa .280“. .00 0.00... 51 data compiled by Dekalb Feeds (2003) showed beef breeds were more efficient than Holsteins. Improved feed conversion efficiency for the BY may be partially due to fewer DOF, whereas if constant DOF was used as the endpoint, results may have shown advantages for Holstein cattle (Garcia-de-Siles et al., 1977). By design, Holstein calf-feds had lighter (P<0.01) initial weights than Angus calf-feds. IHC had heavier (P=0.02) final body weight than NHC. In addition, final body weight was heavier (P<0.01) for calf-feds harvested at the second fat thickness endpoint. ADG was higher (P<0.02) in all periods and overall for BC versus Holstein calf-feds. IHC calves gained 9.8% faster (P<0.01) than NHC calves. Overall, BC consumed more (P<0.01) feed than Holstein calf- feds, and cattle harvested at the second fat thickness endpoint consumed more (P<0.01) feed than those harvested at the first endpoint. Feed conversion efficiency was better (P<0.01) overall for BC, moreover, cattle harvested at the lower fat thickness were more (P<0.01) efficient than those harvested later. Much of the literature contradicts these results, reporting that Holstein cattle have growth and efficiency advantages when compared to British breed cattle (Kidwell and McCormick, 1956; Henderson, 1969; Garcia-de-Siles et al., 1977; Thonney et al., 1981; and Thonney, 1987). However, these results agree with Dekalb (2003) and Perry and Fox (1992) who found beef steers to gain more weight per d. The observed results are confounded with time on feed as the calf- fed Holsteins were on feed an average of 312 d whereas the calf-fed Angus only 172 d. A significant (P<0.01) improvement in overall performance was shown for implanted versus non-implanted Holstein calf-feds. IHC had 9.8% higher ADG 52 than NHC. These findings concur with previous research where ADG was consistently increased with the use of growth-promoting implants (Fox et al., 1989; Perry et al., 1991a and 1991b; Gerken et al., 1995; Duckett et al., 1996; and Duckett and Andrae 2001). DMI was greater for BC than Holstein calf-feds. DMI was also increased by 9.5% with the use of implants, agreeing with the 6% increase in DMI reported by Duckett et al. (1996). When expressed on a percentage of body weight, the calf-fed Angus still had a numerically greater DMI than NHC or IHC (P<0.0001). Additionally, at equal DOF, IHC produced higher (P<0.01) live body weight than NHC, which agrees with results from Perry et al. (1991a,b). Carcass Characteristics The carcass characteristics are presented in Tables 3.4 and 3.5 for yearlings and calf-feds, respectively. USDA yield and quality grades distribution are presented in Tables 3.6 and 3.7. USDA quality grades (QG) were assigned numerical scores for each grade using the American Meat Institute numbering system [Select (+, o, - ) = 18, 17, 16; Choice (+, o, - ) = 21, 20, 19; Prime (+, o, -) = 24, 23, 22]. Marbling score (MS) was assigned a number according to the following scale; assuming "A" physiological maturity, 400-499 = "slight", the amount required for USDA select; 500-599 = "small", the amount required for USDA low Choice; 600-699 = "modest" the amount required for USDA average choice; 700-799 = "moderate“the amount required for USDA top choice. 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R0. 2.... 8.0. 000.00.003.00: .00 5.9 .00.. 00.0 00.0 ...00 00.. .80 00.0 .00.. .00.... . .800 000 0.200 $0000. 3.? .0? 8.9 8.0 .00.. 9...... .000 (.000 .000 «.8... 0.30.05.25.00 00.0 .0.? adv 00.0 00.00 .38 0.... (:00 .00. (0.00 00.300... 0.00.0 00.0 .0.? .00v :0 .000 0.0.0 .30 «.00.. .000 (.00.. 000.0 0.0.2000 8.0 .00v 00.0 0.0 00.0 00.0 00.0 0.0 2.... 0.0 000.0 0.0... 00.0.0200 .0.? 8.9 .0.? «0.0 .0000 m.00.... .0000 (.020 .5... 3.00.0 00.00.... 00.0.0.0 0.0 3.9 .00v 00... 0.80 9.00.0 0.0.0 .00... 0.00 (0.000 60.00.03 008.030: 2.00 b... 00 .200 000 .00 00..: .0... 00:2 .002 1.8.8.0008 .00....00090 000....00 .0. 0000000080 00.. 0000.00 .00 0.00... 55 bomwfio mama 5:96 :03 .8 95:30 33850 No .2832. i- s.-- E... 3.. 2.-- -3. a.-- i- i. .3- Emncmuw m r 9 m w m N F v 52% mm 5 on NN N B 5 8 t 8 865 N v E. m . ..-- S i. met“. «when saga Em: Nom 8m N01. 6:. Noxz 612 NE :6 NE :5 833956 $23525 <8: mm 293 booofio mama 2m; :08 .2 35:35 wmmmmofio No .3252. llll IIII llll llll llll llll IIII IIII llll llll m m v F, m m N F v m N n F «N om N N N 8 mm on mN N N 3 P 2 N o o F a .890. Em: Em: Nom 5m N01. 6:. Noxz 612 NE im NE SE 8:32sz $932» <8: 3 £3 56 Certified Angus Beef. For yearling cattle, there was a significant (P<0.01) breed by fat thickness endpoint interaction for KPH, QG, and MS. HCW was greater (P<0.01) for HY than BY. HCW was similar at both fat thickness endpoints for yearling cattle even though live weights increased. Hot-fat trimming in the harvest facility is the most plausible explanation. Dressing percentages were approximately 2.5 to 3 percentage units below industry norms for cattle with this subcutaneous fat thickness, which further indicates hot-fat trimming occurred in the plant. The Angus yearlings had greater dressing percentages (P<0.01) than Holstein yearlings. Beef cattle breeds tend to have more subcutaneous fat than Holsteins (Martin and Wilson, 1974; Perry and Fox, 1992). Because of the fat trimming, USDA yield grades will also be compromised. Calculated yield grades were drastically different from yield grades established by USDA meat graders, due to adjustments for fat thickness and KPH. HY had the highest (P=0.02) calculated YG. In contrast, BY had the highest (P<0.01) USDA declared YG. Calculated and USDA YG were higher (P5004) at the second fat thickness endpoint. BY cattle had larger (P<0.01) REA than HY. Additionally, as expected, BY had more (P<0.01) subcutaneous fat than HY. Subcutaneous fat thickness was greater (P<0.01) at the second fat thickness endpoint as compared to the first endpoint. Interestingly, HY had a higher (P<0.01) percentage of KPH than BY, and percent KPH increased (P=0.03) at the second fat thickness endpoint for both BY and HY. HY had higher (P<0.01) USDA 06 and MS than BY. Furthermore, MS increased (P=0.02) as fat thickness increased. These results 57 agree with previous research (Nour et al., 1983a; Knapp et al., 1989) where Holstein cattle demonstrated the ability to reach USDA Choice quality grade at acceptable carcass weights. However, studies have reported no difference (Perry and Fox, 1992) in MS or 06 between Holstein and beef breeds, while Henderson (1969) reported advantages in MS and 06 for beef breeds. Increased KPH in Holstein carcasses agrees with findings by Knapp et al. (1989) and Perry and Fox (1992) and appears to be a breed related difference. Similarly, a genetic advantage for REA lies in favor of beef breeds which is supported by prior research where larger REA were reported for beef breeds in comparison to Holstein cattle (Martin and Wilson, 1974; Garcia-de-Siles, 1977; Nour et al., 1983a; Perry and Fox, 1992). In the calf-fed steers, there was a significant breed by fat thickness endpoint interaction for DP, USDA YG, and subcutaneous fat thickness. HCW were heavier (P<0.01) for cattle harvested at the greater subcutaneous backfat thickness endpoint (NHCZ, IHC2, and BCZ vs. NHC1, lHC1, and BC1). Additionally, IHC had heavier (P<0.01) HCW than NHC. DP was higher (P<0.01) for BC versus Holstein calf-feds and DP increased (P<0.01) as fat thickness increased for all calf-fed steers. Calculated and meat grader established YG were greater (P<0.01) at the second fat endpoint for all calf-fed steers. USDA YG were higher (P<0.01) for BC than NHC or IHC. BC had larger (P<0.01) ribeyes than the Holstein calf-feds. In this study, a non-statistical increase (3.5%) in ribeye area was seen for lHC versus NHC. Previously published results (Al-Maamari et al., 1995; Gardner et al., 1995; Roeber et al., 2000) have 58 shown implants increased ribeye size. As expected, subcutaneous backfat thickness was greater (P<0.01) at the second fat thickness endpoint among all calf-fed groups. Backfat thickness was also greater (P<0.01) for BC than NHC or IHC. NHC steers had more (P<0.01) KPH than either IHC or BC, while IHC had more (P<0.01) KPH than BC. KPH was greater (P<0.01) at the second fat endpoint for each of the treatment groups (NHC, IHC, and BC). MS and USDA QG were greater (P<0.01) with longer periods of time on feed and higher levels of subcutaneous backfat for all calf-fed groups. NHC and IHC steers had similar marbling scores and USDA quality grades. These data indicate that longer time of feed and greater fat cover improves quality grade and marbling characteristics in calf-fed Holstein and Angus steers, with no apparent breed difference. As previously mentioned, these results agree with research findings that reported higher YG (Knapp et al., 1989) and larger REA for beef breeds than Holsteins (Martin and Wilson, 1974; Garcia-de-Siles, 1977; Nour et al., 1983a; Perry and Fox, 1992). Previous research has shown that Holsteins have more KPH than beef breeds (Perry and Fox, 1992; Knapp et al., 1989). Additionally, Perry and Fox (1992) reported similar QG and MS between breeds. Tables 3.6 shows the USDA yield grade distribution for all cattle. HY1 and HY2 had a greater percentage (28.1 and 10.3 %, respectively) of Yield Grade 1 carcasses than BY1 or BY2 (5.0 and 0 %, respectively, while BY1 had the highest percentage (7.5 %) of Yield grade 3 carcasses. NHC1 and lHC1 cattle had the highest percentage of Yield Grade 1 carcasses (37.1 and 40.0 %, respectively). with NHC2 and BC1 grading 3.0 and 5.9 % Yield Grade 1. 59 Consequently, BC2 cattle had the highest percentage (97.2 %) of carcasses that were Yield Grade 3 or 4. Table 3.7 show the USDA quality grade distribution. It is apparent from this table that cattle in the second harvest group had a higher percentage of carcasses grading USDA Prime. HY2 had the largest percentage of carcasses grading USDA Prime (17.2 %), however, all groups of carcasses were at least 85% Choice or Prime except for lHC1 (62.9 %). Chemical composition of longissimus dorsi (LD) steaks and L*, a*, and b* values for yearling cattle are shown in Table 3.8. For yearling cattle, no differences were seen in protein content. However, BY had a greater (P<0.05) percent moisture. Moisture percent decreased (P<0.01) and fat percent increased (P<0.01) as cattle deposited more subcutaneous fat, indicating that higher degrees of subcutaneous fat were. indicative of more intramuscular fat deposition. L* values were higher (P<0.01), while a* and b* values were lower (P<0.01) for BY versus HY. Moreover, L” values increased (P<0.01), while a” and b* values decreased (P<0.01) with increased levels of subcutaneous fat thickness. Chemical composition and L*, a* and b* values for calf-feds are shown in Table 3.9. Among calf-fed steers, there was a significant (P5002) breed by fat thickness endpoint interaction for percent moisture, percent fat, L*, a*, and b* values. Percent moisture was lower. (P<0.01) for BC than for calf-fed Holstein steers. Moisture content of the LD muscle was similar for NHC and lHC steers. The similarity between moisture, fat and protein content of the LD muscle of NHC and lHC steers suggests the growth-promoting implant sequence used had little 60 55v matoeoaam 95:: 53> 959 55.3 28.2 E08835 «5895 «$5.25 .3 B 3298 838.25 .582... $99.25 5 3 Ben 3 £5295 u Eurmm ”85.0% .5895 $83.25 5 .6 £3305 n E“. 56 .9 >5 855% .385 6 £5205 u mm. :2me came 9: Co .25 92:56 Boon. cm 2 80¢ u omen. 52:233.: .833 moo: 26:3 208 u 93:5: .29; .323» moo: 2.3 22: u 93:5: 326. - .b .noo 2 83 u omen. 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Similar to yearling cattle, as subcutaneous fat thickness endpoint increase, moisture and protein percent decreased (P<0.01) and percent fat increased (P<0.01). Additionally, L* values were higher (P<0.01) and b* values were lower (P<0.01) for BC versus Holstein calf-feds. At the second fat thickness endpoint L* values increased (P<0.01), and a* and b* values decreased (P<0.01). As subcutaneous fat level increased for cattle, percent fat in the LD increased for all cattle. Additionally, at higher fat thickness endpoints, L* values were increased indicating somewhat lighter coloration of the lean. Based on the correlation between increased fat percent and increased L* values, it appears that marbling content of the LD influenced L* readings at the higher fat thickness endpoint. In contrast no differences in fat percentage were evidenced between Holstein or Angus cattle, however, steaks from Angus cattle had higher L* values and lower b" values. Therefore, Angus cattle produce steaks with lighter lean and a more yellow coloration. a* values decreased at the second fat thickness endpoint and as DOF increased. Based on these data it appears steaks from younger carcasses have a slightly more red coloration than older carcasses. Finally, implants (IHC vs. NHC) had little impact on lean color scores. 63 Sensory Evaluation and Shear Force Table 3.10 and Table 3.11 display results for sensory panel evaluation and shear force determination of longissimus dorsi steaks for yearling and calf- fed steers, respectively. HY had less (P=0.03) connective tissue and displayed more desirable (P<0.01) myofibrillar and overall tenderness when compared to BY. In addition, as cattle were fed to higher fat thickness endpoints, myofibrillar tenderness increased (P=0.03). In agreement with sensory data, shear force values were lower (P<0.01) for HY versus BY, and shear force values improved (P=0.03) at the second fat thickness endpoint. In contrast, BC had less (P<0.01) perceived connective tissue, and showed improved (P5005) myofibrillar and overall tenderness when compared to IHC. Amount of perceived connective tissue increased (P=0.02) at the second fat thickness endpoint. Shear force data agree with sensory evaluations, showing lower (P_<.0.01) values for BC versus IHC. There were no differences in sensory or shear force data for implanted versus non-implanted Holstein calf-feds (IHC vs. NHC). The actual age of the steers is unknown, but the Holstein calf-feds were on feed an average of 312 d vs 172 d for BC. Additionally, HY were on feed an average of 170 d vs 116 d for BY. It is unknown how this difference in time on feed affected tenderness. For yearlings, it appears that increased DOF had no adverse effects on tenderness, however, there may be a threshold in terms of DOF and the impacts on tenderness. Much of the previous research reports little or no difference in sensory and tenderness attributes between Holstein and Angus cattle (Callow, 1961; Branaman et al., 1963; Judge et al., 1965; Armbruster et al., 1983). 64 530925 .5895 $353 .3 S cows Co £3305 u 29mm ”885% E895 886% E .6 £3205 u 2“. 56 .2, >£ 855% Ben .0 .9323 u mac 22me cows. 9.: .o .25 2356 2300.“.a co_fic_E§mn 85. 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(1964) and Ziegler et al. (1971) higher flavor, juciness and overall acceptability of Herefords versus Holstein cattle, while Thonney et al. (1991), and Perry and Fox (1992) reported improved tenderness and overall acceptability for Holstein over beef breeds. Economic Analysis Economic data are presented in Table 3.12 and Table 3.13 for yearling and calf-fed steers, respectively. There was a significant (P=0.02) breed by fat thickness endpoint interaction for COG. COG was lower (P<0.01) for BY in comparison to HY. HY were on feed an average of 170 d vs. 116 d for BY. More DOF increases yardage, feed, and interest costs. Two HY2 steers died during the trial adding death loss cost as well. In contrast, HY carcass values were higher than carcass values for BY. On average, HY2 carcasses were 27 kg heavier and nine more carcasses graded USDA Prime than BY2. A six percent premium for Prime over Choice was used in the calculation. Although carcass value was higher for HY, gross margin was higher (P<0.01) for BY versus HY, indicating that losses in feedlot performance offset the additional value of HY carcasses. Similarly, breakeven feeder calf price for BY was higher (P<0.01) than HY. This price represents the price a producer could pay for these cattle in order to breakeven. For calf-feds there was a significant (P<0.01) breed by fat thickness endpoint interaction for COG. Similar to yearling findings, BC had a significantly lower (P<0.01) COG than Holstein calf-feds. In addition IHC had a lower (P<0.01) COG than NHC. 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Breakeven feeder calf price was similar for BC and NHC, however, IHC had a higher (P<0.01) breakeven than BC or NHC. Data from Angus cattle in the first fat thickness endpoint group for both yearling and calf-fed steers was also included in the tables, although data for Holstein cattle in the first fat thickness endpoint group was unavailable. For yearlings, BY1 displayed higher carcass value 1 and carcass value 2 than BY2, but lower value than HY2. BY1 also had a higher gross margin 1 and 2 than BY2 or HY2. BY1 had a lower breakeven feeder calf price than BY2, had a similar breakeven price per kg to HY2, but had a higher breakeven price per cwt than HY2. Carcass value 1 and 2 were lowest for BC1 when compared to NHC2, IHCZ, and BC2, while gross margin 1 was highest and gross margin 2 was higher than than NHC2 and IHCZ, but similar to BC2. BC1 had similar breakeven prices as NHC2 and BC2, but had a significantly lower breakeven than IHC2. 7O Angus cattle have significant advantages in terms of COG in comparison to Holstein cattle, whereas, Holstein cattle produce higher valued carcasses. However, increased carcass value seen for Holstein cattle was offset by high cost of production, resulting in lower gross margin and lower feeder calf breakeven prices. In addition, implanting cattle increases carcass value and gross margin. This agrees with results from Duckett et al. (1996) and Duckett and Andrae (2001). 71 Chapter 4 SUMMARY AND CONCLUSIONS Holstein (HY) steers fed to a similar fat thickness endpoint as Angus (BY) steers required more time on feed and were less efficient. These may be deterrents for cattle feeders, when considering feeding Holstein cattle. However, Holstein yearling cattle proved to perform comparable to Angus yearling cattle in terms of ADG and DMI. In contrast to the yearling data, calf-fed Holstein steers gained significantly slower than calf-fed Angus steers, and also consumed less feed. Likewise, Angus calf-feds had better feed conversion efficiency than the Holstein calf-feds. The Angus calf-fed steers performed exceptionally well in this study and may not accurately represent the breed. These data suggest that Angus cattle may have advantages in terms of feedlot performance, especially when fed as calves. Additionally, implanted Holstein calves had numerical advantages in final body weight, ADG, and DMI, although feed conversion seemed to be unaffected by implant treatment. Holstein cattle have an advantage with respect to carcass traits such as external fat thickness, as they are able to grade Choice at lower fat thickness endpoints than Angus steers. However, Angus cattle have significant muscling advantages as evidenced by larger REA for both Angus yearling and calf-feds over Holstein yearlings and catf-feds. Dressing percent was higher for Angus over Holstein. Angus steers also had an advantage in internal fat as KPH fat percentage was lower for Angus than Holstein in both finishing systems. In addition, KPH was significantly higher at the second fat thickness endpoint for 72 calf-feds. Holstein yearlings had advantages in quality grade and marbling score over Angus yearlings. Moreover, HY2 had higher scores than HY1. These results may be partially explained by genetic differences and more days on feed for Holstein steers. No trends between breed for QG and MS were apparent for calf-fed steers. Nonetheless, steers in the second fat thickness endpoint group for all breeds had better GO and MS, revealing that increased time on feed may be beneficial in terms of increasing beef quality. Meat samples from steers in the second fat thickness endpoint for each breed had higher fat content than those in the first fat thickness group. These data suggest that as external fat thickness increased, fat content of the longissimus dorsi increased as well. Additionally, as external fat thickness was increased, moisture and protein percent in the longissimus dorsi was decreased, indicating an inverse relationship between fat content with respect to moisture and protein content. Angus cattle had higher L* values and lower b* values than Holstein cattle. Furthermore as cattle were fed to higher fat thickness endpoints, L* values increased and a* and b* values decreased. Increased marbling in the LD at the second fat thickness endpoint appears to have influenced L* readings when comparing endpoint one to endpoint two, with the higher fat content resulting in higher L* or lighter color values. However, no fat difference was apparent between Angus and Holstein cattle, resulting in the higher L* values for Angus to indicate a lighter lean color. Nonetheless, all values fell within acceptable ranges for L*, a* and b*. Implant had no effect on color readings. 73 Holstein yearlings produced steaks that had less connective tissue, more myofibrillar and overall tenderness, and a lower shear force value than black- hided yearlings. Furthermore, yearling cattle had improved shear force values when fed to the second fat thickness endpoint. In contrast, Angus calf-feds had less connective tissue, more myofibrillar and overall tenderness, and a lower shear force value than Holstein calf-feds. Finally, implanted Holstein carcasses had similar sensory panel scores as non-implanted Holstein carcasses. It is apparent from these data that Angus cattle are more economical in terms of COG. This advantage may be attributable to greater feed efficiency and fewer DOF. With increased DOF, feed, yardage and interest costs increase, translating to more total costs. However, it is important to note increased carcass value of the Holstein cattle. Clearly, Holsteins have the ability to grade as well as Angus cattle at lower fat thickness endpoints, and may possibly have greater genetic potential to grade USDA Prime based on the current study. However, in terms of gross margin, Angus cattle once again show superiority. Breakeven feeder calf prices were lower for Holstein yearlings than Angus yearlings, whereas they were higher lower for Angus calf-feds than Holstein calf- feds. During this trial yearling and calf-fed steers were fed in different facilities, making comparisons between the two feeding systems essentially meaningless, as feeding system differences would be confounded with location differences. Housing all animals on trial in the same location would allow for more meaningful comparisons to be made between all cattle groups. However, due to limitations 74 of pen space a more applicable solution for this trial would have been to replicate the study in both dirt floor pens and the slatted floor pens. With equal representation of each group in both locations, variation due to location could be accounted for and more comparisons could be made. Cutout data for this trial was collected on a group basis, with all cattle from a backfat thickness endpoint group within each breed being pooled together. A more desirable situation would have been to select half of the animals from each pen, and perform a complete cutout test on then, keeping individual cutout data for each pen. This would allow for a more complete analysis of cutout data. Additionally, cut-out data for Holstein cattle in the first fat thickness endpoint group was not able to be used due to a lack of proper sorting of these cattle before they were fabricated. Having this data would make the economic comparisons more interesting and valuable. Results from these data reveal interesting differences in Holstein and Angus cattle and the efficacy of feeding yearlings or calf-feds. This research indicates that Holstein and Angus cattle are similar in terms of their ability to grade USDA Choice, however, Holstein cattle are able to grade Choice with less subcutaneous fat cover than Angus. However, it takes Holstein cattle much longer to deposit external fat. Additionally, eating quality is similar between steaks from Angus and Holstein carcasses. Nonetheless, Holstein cattle require more DOF to achieve subcutaneous fat levels typical of current industry standards. Increased DOF leads to increased feed, yardage, and interest costs resulting in a higher overall COG for Holstein when compared to Angus. Holstein 75 carcasses tended to be heavier than Angus carcasses and also had more carcasses grading USDA Prime. These combined factors lead to increased carcass value for Holstein cattle versus Angus. Although carcass value was higher for Holstein than Angus, gross margin, which represents the price received after COG is accounted for, was higher for Angus than Holstein. Increased DOF, along with, decelerating feedlot performance may offset any improvement Holstein cattle have in terms of quality grade. The implant program used in this trial did not impact the eating quality of steaks from implanted versus non-implanted carcasses. Future research comparing Holstein and Angus cattle would prove most beneficial in the area of a calf-fed finishing system, as the diminishing feedlot performance for Holstein yearlings speaks for itself. Based on discussion with Packerland Packing Company, data collected in their plants suggests non- implanted calf-fed Holsteins produce more red meat yield as a percentage of HCW than implanted calf-fed Holsteins. 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Food Sci. 51:839-840. Savell, J.W., R. Miller, T. Wheeler, M. Koohmaraie, S. Shackelford, B. Morgan, C. Calkins, M. F. Miller, M. Dikeman, F. McKeith, G. Dolezal, B. Henning, J. Busboom, R. West, F. Parrish, and S. Williams. Standardized Wamer- Bratzler shear force procedures for genetic evaluation. Available at: http://meat.tamu.edulshearstand.html. Accesses January 7, 2003. Scanga, J.A., K.E. Belk, J.D. Tatum, T. Grandin, and G.C. Smith. 1998. Factors contributing to the incidence of dark cutting beef. J. Anim. Sci. 76:2040- 2047. 83 Schlegel, ML. 1999. Influence Of Bovine Somatotropin Administration To Holstein Steers On Growth, Lipid Metabolism and Carcass Characteristics. PhD. Dissertation. Michigan State University. East Lansing, MI. Sindt, M., R. Stock, and T. Klopfenstein. 1991. Calf versus yearling finishing. Univ. of Neb. Beef Cattle Rep. pp. 42-43. Smith, G.C., G.R. Culp, and Z.L. Carpenter. 1978. Postmortem aging of beef carcasses. J. Food Sci. 43:823-826. Smith, G.C., J.W. Savell, H.R. Cross, Z.L. Carpenter, C.E. Murphey, G.W. Davis, H.C. Abraham, F.C. Parrish, Jr., and B.W. Berry. 1987. Relationship of USDA quality to palatability of cooked beef. J. Food Quality. 10:269-286. Thonney, M.L., E.K. Heide, D.J. Duhaime, A.Y.M. Nour, and PA. Oltenacu. 1981. Growth and feed efficiency of cattle of different mature sizes. J. Anim. Sci. 53:354-362. Thonney, M.L., A.Y.M. Nour, J.R. Stouffer, and W.R.C. White. 1984. Changes in primal cuts with increasing carcass weight in large and small cattle. Can. J. Anim. Sci. 64:29-38. Thonney, ML. 1987. Growth, feed efficiency and variation of individually fed Angus, Polled Hereford and Holstein steers. J. Anim. Sci. 65:1-8. Thonney, M.L., T.C. Perry, G. Armbruster, D.H. Beermann, and D.G. Fox. 1991. Comparison of steaks from Holstein and Simmental x Angus steers. J. Anim. Sci. 69:4866—4870. USDA. 1998. National Food Review, Economic Research Service. 13:1. USDA. 2001. Livestock grade fact sheet. Available at: www.ams.usda.gov/lsg/standlsteeryield.pdf. Accessed May 12, 2003. USDA - AMS. 2003. USDA Certified Beef Programs. Available at: http://www.ams.usda.gov/Isg/certprog/speccomp.pdf. Accessed: May 5, 2003. USDA — ERS. 2003. Agricultural Income and Finance Outlook. March 2003. Appendix table 5, page 63. Available at: http:/Iwww.ers.usda.gov/publications/so/view.asp?f=economicslais-bb. Accessed: October 14, 2003. USDA-NASS. 2003. Published Estimates Data Base, Available at: http:/Iwww.nass.usda.gov:81/ipedbl. Accessed: October 14, 2003. 84 Van Koevering, M.T., D.R. Gill, F.N. Owens, H.G. Dolezal, and CA. Strasia. 1995. Effects of time on feed on performance of feedlot steers, carcass characteristics, and tenderness and composition of longissimus muscles. J. Anim. Sci. 73:21-28. Webb, A.S., R.W. Rogers, and B.J. Rude. 2002. Review: Androgenic, estrogenic, and combination implants: production and meat quality in beef. Prof. Anim. Sci. 18:103-106. ' Ziegler, J.H., L.L. Wilson, and OS. Coble. 1971. Comparisons of certain carcass traits of several breeds and crosses of cattle. J. Anim. Sci. 32:446-450. 85 APPENDIX 86 Appendix A Per Capita Consumption and Deflated Prices“ for Beef, 1960 through 2000 149.87 79 7.3 140.71 - 7.4 131.7. 8,0 787.5 .9 122.6- 00031.2 63 ‘5 8: 59 71 702 . 76 a ' . - 82 . 51 ° - .., “e o“ e '70 a 113.5 3. “- 7.7 3 104.4- ° 91208.9 as as 5- 95.3- 9.39;” - 9.7 u,- ss.3- 4.5...“ 77.2_ 97. a...” 68.1 . . . . 27.2 31 .8 36.3 40.9 45.4 Per capita consumption, kg 3 CPI, 1982 through 84 = 100 Adapted from Purcell, 2002 87 Appendix B Top Five “Greatest Quality Challenges” Identified by 2000 National Beef Quality Audita Rank bj Sector Strategy Purveyor, Workshop Retailer, and Identified Challenge Participants Producer Packer Restaurateur Inadequate Tenderness 3 1 4 (tie) 2 (tie) Lack of Uniformity 1 2 1 2 (tie) Insufficient Marbling 4 3 4 (tie) 1 Presence of Injection -—- 4 --- --- Sites Inadequate Flavor of --- 5 -—- 5 Beef Carcass Weights Too --- -- 2 --- High Excess Fat Cover --- --- 3 4 Reduced Quality Grade 5 --- 4 (tie) --- Due to Implants Inappropriate Carcass 2 --- --- --- Size and Weight aSource: Executive Summary: Results of the National Beef Quality Audit - 2000 In: G.C. Smith (ed.) Improving the Quality, Consistency, Competitiveness and Market- share of Fed-beef: The Final Report of the Third Blueprint for Total Quality Management in the Fed-Beef (Slaughter steer/heifer) Industry; National Beef Quality Audit — 2000. p. 4-10. National Cattlemen’s Beef Assoc. Centennial, CO. 88 Appendix C Current Branded and Certified Beef ngramsa USDA Program Name Description Certified American Foods Group (AFG) . Black Angus Reserve Prime 51% black, USDA ane X AFG Black Angus Reserve . Premium Choice 51% black, upper 2/3 USDA Chorce X AFG Black Angus Reserve Choice 51% black, lower 1/3 USDA Choice X AFG Black Angus Reserve Select 51% black, Slight‘°-sngllt99 x Retained ownership, premiums for Angus 83R Country Meats enetics, non-implanted and non branded . Known Angus-type, licensed lots, must meet Certified Angus Beef carcass specs X Certified Hereford Beef Choice and Select product, AHA Live Specs X Coleman Natural Beef Cattle raised under natural specifications Creekstone Farms Black Angus . . Beef, Master Chef 51 % black, Modest or higher marbling X Creekstone Farms Black Angus 51% black, Lower 1/3 USDA Choice and X Beef, Chefs Table upper 1/2 USDA Select Del Monte Meat’s Certified . . Premium Choice Beef Modest or higher marbllng X Elkhorn Valley Packing Premier 51% black, upper 2/3 USDA Choice and X Angus Beef USDA Prime E23” “"6” Pac"'"‘* Angus 51% black, lower 1/3 USDA Choice X . 51 % black and Red Angus genotype, Smalls0 Excel Corp. Angus Prlde or higher marbling X Excel Corp. Sterlingfiilver Modest or higher marbling X Farmland Angus Beef 51% black, Small50 or higher marbling X Farmland Certified Premium Beef Modest or higher marbling X lBP’s Chairman's Reserve Beef Modest or higher marbling X . Lean all natural beef raised and fed without Laura 8 Lean Beef antibiotics or growth hormones . . Goal to produce branded, premium quality Lean leousm Beef 00' beef for the high-end restaurant market . Natural product, must be on feed 100 days Maverlck Ranch Beef with specified amount of vitamin E Natural product, no antibiotics, no growth Meyer Natural Angus mmotants, over 50% Angus by genetics Breed specific branded beef program, Mme” Range Natura' Beef retained ownership, 50% Piedmontese M°pa° s Steakmuse C'ass'c 51 % black, Modest or higher marbling x Aquus Nebraska Com-Fed Beef Inc. Production guidelines must be followed, BOA certification, source verification to ranch of origin 89 , USDA Brandname Specification, No implants ggljgiyaBrlezfAll Natural Aged of antibiotics 100 days prior to harvest, USDA X Choice , USDA Brandname Specification, No implants 23:15:23" s A" Natural Tender of antibiotics 100 days prior to harvest, USDA Select OEgon Trail Supreme Beef Modest or higher marblirg Oregon Trail Premium Beef Egg: 1/3 USDA Choice and upper 1/2 USDA X . . Producer certification required and no Painted HIIIS Natural Beef implants, antibiotics, or animal by-products . USDA Process Verified, source verified, PM Beef Group Ranch to Retall vitamin E fed, guaranteed tender, agd beef . . 51% Angus, data collection and value—based Premium Gold Angus Platinum rid available, Upper 2/3 USDA Choice 51% Angus, data collection and value-based Premium Gold Angus Blue Ribbon grid available, Lower 1/3 USDA Choice and X Select . Cattle marketing cooperative implementing a Eggchgfisvge'rrlgssance systems approach to center of the plate beef pe ’ ' production, allows % Brahman USDA Process Verified, genetically sources Red Angus Assn. Of America Red Angus-influenced cattle, Supplies “Agus” beef product lines . Hereford and Hereford/English cattle, 5:38:23 5;"? P'em'u'“ marketed and distributed by Premium Quality X Foods, Inc. Ridgefield Farms Premium . . Hereford Beef USDA Select and USDA ChOlce, breed clalm 32?“ P""‘”""'" 3'3“ Angus Modest or higher marbling, 51% black . 51% black, lower 1/3 USDA Choice and Slmplot Black Angus Beef upper 1,2 USDA Select X Modest or higher marbling, does not require Swift/EA Miller Chef’s Exclusive medium or fine marbling, does not require A X maturity 0 Swift Angus Select Beef UfntgAyseelect, 51 lo black or Red Angus X Swift Premium Black Angus Beef USDA Choice or higher, 51 % black X Swift Premium Classic Beef Modest or higher marbling X SYSCO Butcher’s Block Angus USDA Choice or higher, 51 % black or Red X Beef Angus genogpe 3:300 Butcher‘s BIOCK Reserve Modest or higher marbling X 0 Tyson's Classic Angus Beef (53:13 :23“ and Red Angus genotype, USDA X Washington Beef, Inc. Quality 51% black, upper 2/3 USDA Choice and X Plus Angus Beef USDA Prime Washington Beef, Inc. Premium 51% black, lower 1/3 USDA Choice and X Angus Beef USDA Select Adapted from AMS website http:/Iwww.ams.usda.govllsg/certprog/speccomp.pdf and Drover’s Journal http:/lwww.drovers.com/‘fileUploads/aIliancechart_3.pdf. 90 Appendix D Meat Descriptive Attribute Ballot Name Rep Date Sample Juiciness Muscle Fiber Overall Connective Tenderness Tenderness Tissue Warm-up Juiciness Muscle Fiber and Overall Tendemes_s Connective Tigsue Amount 8 Extremely Juicy 8 Extremely Tender 8 None 7 Very Juicy 7 Very Tender 7 Practically None 6 Moderately Juicy 6 Moderately Tender 6 Traces 5 Slightly Juicy 5 Slightly Tender 5 Slight 4 Slightly Dry 4 Slightly Tough 4 Moderate 3 Moderately Dry 3 Moderately Tough 3 Slightly Abundant 2 Very Dry 2 Very Tough 2 Moderately Abundant 1 Extremely Dry 1 Extremely Tough 1 Abundant 91 no? to F 6000009.. Eng:3300.000:.00093323350 0_nm__m>< .0000 $00 m0fiE=mm 00:053. .mm< 000 52 50 E00 ma< 22. 0:2. >02 5.4 .05. 00“. cm... 50> 0025 25:22 900030 .2 00:00 025 000?? 0050 02:5 no? (or fi0mm0oo< £000:5500.000:.mmmGBBEEEum 0_nm__m>< .0000 900 mofiezmm 00203.5 .mm< 000 >02 “00 E00 mmm. 22. 0:2. ~02 a< .05. n0... :2. 50> 0005:4205. Eco co.— 00t0m 00030000.. 0065 00:5 92 APPENDIX F Interest rates on agricultural products, 1993-2002 Year Interest Rate 1993 7.83% 1994 8.57% 1995 8.95% 1996 8.08% 1997 8.28% 1998 8.13% 1999 7.95% 2000 8.61% 2001 6.73% 2002 5.43% Source: USDA - ERS. Agricultural Income and Finance Outlook. March 2003. Appendix table 5, page 63. 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