THE EFFECT OF ADDING A LIQUID SUSPENSION 0F ANHYDROUS AMMONIA, MINERALS AND MOLASSES TO CORN SIMGE AT ENSILING, 0N FERMENTATION PARAMETERS AND BEEF CATTLE PERFORMANSE Thesis for the Degree of M. S. MICHIW STATE UNIVERSITY DAVID BEATI'IE 1970 THESE L I B R A R Y Michigan 31523 Universuy "W NASlJ RETURNING MATERIALS: PTace in book drop to LlaRARJES remove this checkout from “ your record. FINES will be charged if book is returned after the date stamped be10w. ,- ~ I »gn e» 23 e270 Ufirffirwfi ABSTRACT THE EFFECT OF ADDING A LIQUID SUSPENSION OF ANHYDROUS AMMONIA, MINERALS AND MOLASSES TO CORN SILAGE AT ENSILING, ON FERMENTATION PARAMETERS AND BEEF CATTLE PERFORMANCE BY David Beattie A feeding trial and two metabolic studies were conducted to inves- tigate the effect of corn silage treated with a liquid suspension of an- hydrous ammonia, minerals and molasses (Pro-Sil) on yearling steer per- formance and metabolic parameters. In the feeding trial, 108 head of yearling steers were fed either all silage or 60% silage + 40% shelled corn rations. Silages treated with three levels of Pro-Sil were compared to urea-treated silage and both negative (no protein supplement) and positive (protein supplement fed) control silages. The Pro-Sil and urea additions at ensiling increased crude protein equivalent of the treated silages (P4{.01), generally in proportion to the level of non-protein nitrogen (NPN) added. Nitrogen losses for all treated silages were less than 52 of the amounts added. All treated silages showed increased water insoluble ni- trogen (probably true protein) fractions. The NPN from Pro-Sil was main- ly recovered as ammonium salts of organic acids, urea was recovered as intact urea (58%) and ammonium salts. All treated silages showed significantly (P4:.01) higher lactic acid content and the higher levels of Pro-Sil additions (25 and 35 Kg. per 1000 Kg.) significantly (P4:.05) decreased acetic acid levels. Steer performance was similar for Pro-Sil 12 (25 Kg. Pro-Sil per 1000 Kg.), urea and positive control silages and significantly (P<.01 David Beattie and P«(.05) higher for these treatments over all other treatments at both concentrate levels. No significant differences were found in carcass characteristics within or between concentrate levels. Feed costs favored the Pro-Sil 12 and urea-treated silages at both concentrate levels. Metabolic studies at both concentrate levels indicated no signifi- cant differences in apparent dry matter digestibility, nitrogen digesti- bility or nitrogen retention between treatment groups. Apparent dry matter digestibility was higher on the 402 concentrate ration but differ- ences were not significant. Rumen ammonia and blood urea levels were higher in steers fed treated silages on the all silage program (not significant). The same trend was not apparent on the 40X concentrate ration but blood urea levels were higher for Pro—Sil 14 silage (35 Kg. Pro-Sil per 1000 Kg.) than the other treatments (not significant). Rumen volatile fatty acid (VFA) concentrations were similar at both concentrate levels, propionic and butyric acids were slightly higher for treated silages on the all-silage program and propionic acid was also higher for treated silage rations on the 40% concentrate program, however, differences were not significant. Peak production of VFA's occurred at two hours post-feeding on all silage rations and at four hours post-feed- ing on the 40% concentrate rations. Differences again were not significant. THE EFFECT OF ADDING A LIQUID SUSPENSION OF ANHYDROUS AMMONIA, MINERALS AND MOLASSES TO CORN SILAGE AT ENSILING, ON FERMENTATION PARAMETERS AND BEEF CATTLE PERFORMANCE BY David Beattie A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Animal Husbandry 1970 David Beattie candidate for the degree of Master of Science Dissertation: The Effect of Adding a Liquid Suspension of Anhydrous Ammonia, Minerals and Molasses to Corn Silage at Ensiling, on Fermentation Parameters and Beef Cattle Performance Outline of Studies: Major Area: Animal Husbandry (Ruminant Nutrition) Minor subject: Biochemistry Biographical Items: Born: October 9, 1939: Perthshire, Scotland Undergraduate studies: University of Reading, England 1958 - 1961 Graduate studies: Michigan State University, 1969 - 1970 Experience: Farm Manager, Kent, England 1961 - 1966 Lecturer, Ridgetown College of Agricultural Technology, Ridgetown, Ontario, Canada 1966 - 1969 Member: Canadian Society of Animal Production Ontario Institute of Agrologists Agricultural Institute of Canada ii ACKNOWLEDGEMENT The author extends his deep appreciation to Dr. Hugh E. Henderson for his valued guidance and counsel during his graduate program. The author is also indebted to Dr. J. T. Huber, and Dr. Richard W. Luecke, as members of his graduate committee, for their sound advice and participation in his graduate program, and to Dr. Werner G. Bergen for his advice and assistance throughout the program. The author also wished to thank Dr. Ronald H. Nelson and Dr. J. A. Hoefer for making the facilities of Michigan State University and the Michigan Agricultural Experiment Station available for this research. Appreciation is extended to all members of the Department of Animal Husbandry for their kindness and hospitality. The author is indebted to his employers, The Ontario Department of Agriculture and Food, for leave of absence and financial support dur- ing the course of his graduate program. The writer extends his sincere gratitude to his wife, Lynda, for her interest and encouragement throughout his course of study, and for the considerable sacrifices which made it possible. iii TABLE OF CONTENTS List of Tables List of Figures List of Appendix Tables I. II. III. IV. Introduction Literature Review Fermentation of Corn Silage Effect of Silage Additives on Silage Fermentation In Vivo Evaluation of Silage Additives In Vitro Evaluation of Silage Additives Effect of Silage Additives on Beef and Dairy Cattle Performance Materials and Methods AEgperiment l - Yearling Steer Feeding Trial Design Harvesting of Silages Feeding Trial Feeding Regime Silage Analysis Experiment 2 - Metabolism Study with All Silagg Rations Design Harvesting of Silages Silage Analysis Feeding Regime Sample Collection Laboratory Analysis Experiment 3 - Metabolism Study with 40% Concentratg Rations Statistical Analysis Results and Discussion ‘Experiment 1 - Feeding Trial Chemical Analysis of Silage Nitrogen Fractions Organic Acids Effect of Additives on Feedlot Performance All Silage Ration 602 Silage 40% Concentrate Ration All Silage vs. 40% Concentrate Ration iv Page vi viii \IUIU'i 10 12 15 15 15 16 20 21 21 22 22 22 23 23 24 25 26 26 27 27 27 27 32 34 34 36 41 Table of Contents (Cont.) ggperiment 2 - Metabolism Study with All Silage Rations Chemical Analysis of Silage Nitrogen Fractions Organic Acids Digestion Parameters Rumen and Blood Parameters Rumen Volatile Fatty Acids _§§periment 3 - Metabolism Study with 402 Concentrate Rations Digestion Parameters Rumen and Blood Parameters Rumen Volatile Fatty Acids V. Summary Bibliography Appendices Appendix I - Sample Calculation Appendix II - Design of Experiments 71 72 Table 10 ll 12 13 14 15 16 17 18 19 LIST OF TABLES Pro-Sil Formulation Formulation of Mineral Supplement Formulation of Urea-Mineral Supplement (for ensiling) Average Chemical Analyses of Silages (Expt. 1) Effect of All Silage Ration on Rate of Gain and Feed Efficiency (Expt. 1) Effect of All Silage Ration on Carcass Quality (Expt. 1) Effect of 402 Concentrate Ration on Rate of Gain and Feed Efficiency (Expt. 1) Effect of 40% Concentrate Ration on Carcass Quality (Expt. 1) Effect of All Silage vs. 40% Concentrate Ration on Rate of Gain, Feed Efficiency and Carcass Quality (Expt. 1) Effect of All Silage vs. 402 Concentrate Ration on Carcass Quality (Expt. 1) Average Chemical Analyses of Silages (Expts. 2 and 3) Effect of All Silage Ration on Digestion Parameters (Expt. 2) Means of Blood Urea Values (Expt. 2) Means of Rumen Ammonia Values (Expt. 2) Mean Rumen Acetic Acid Concentrations (Expt. 2) Mean Rumen Propionic Acid Concentrations (Expt. 2) Mean Rumen Butyric Acid Concentrations (Expt. 2) Effect of 40% Concentrate Ration on Digestion Parameters (Expt. 3) Means of Blood Urea Values (Expt. 3) vi Page 19 19 23 28 35 37 38 42 43 44 52 52 55 55 56 58 59 List of Tables (Cont.) Table 20 21 22 23 Means of Rumen Ammonia Values (Expt. 3) Mean Rumen Acetic Acid Concentrations (Expt. 3) Mean Rumen Propionic Acid Concentrations (Expt. 3) Mean Rumen Butyric Acid Concentrations (Expt. 3) vii 61 62 LIST OF FIGURES Schematic Illustration of Equipment used in applying Pro-Sil to corn silage in a tower silo Mean Total Nitrogen, Water Insoluble Nitrogen and Water Soluble NPN Concentrations, as Z of DM (Expt. 1) Mean Total Water Soluble NPN (as Z of DM) of Silages, showing Actual Urea and Ammonia Nitrogen Fractions (Expt. 1) Mean Organic Acid Fractions (as Z of DM) for Respective Silages (EXpt. 1) Mean Total Nitrogen, water Insoluble Nitrogen and water Soluble NPN Concentrations, as z of DM (Expt. 2 & 3) Mean Total Water Soluble NPN (as Z of DM) of Silages showing Actual Urea and Ammonia Nitrogen Fractions (Expt. 2 & 3) Mean Organic Acid Fractions (as Z of DM) for Respective Silages (Expt. 2 & 3) viii 29 31 33 46 47 49 Table Appendix I 1 AWendi): I? l 2 LIST OF APPENDIX TABLES 321.: Appendix I 1 Experiment 2 - Metabolism Study - Silage Acetic Acid Analysis of Variance Appendix II 1 Experiment 1 - Feeding Trial, Design of Experiment 2 Experiment 2 - Metabolism Study, Design of Experiment 3 Experiment 3 - Metabolism Study, Design of Experiment ix Page 71 72 73 74 I. INTRODUCTION Use of whole plant corn silage as a feed for ruminant animals is now a widely accepted practice on progressive beef and dairy farm opera- tions. The corn plant, of all the silage crops, gives the highest yield of total digestible nutrients per acre, and as silage, is readily consum- ed in large quantities by both beef and dairy animals. The corn plant and hence the ensuing corn silage, requires supplementation with substan- tial amounts of crude protein and minerals to meet the requirements of beef cattle as listed by the National Research Council (1970). Crude protein and mineral content of corn silage are known to vary with type of soil, soil fertility levels, climate and plant variety, but supple- mentation is generally required. Extensive research over the last fifty years has conclusively shown that ruminant animals have a unique ability to utilize sizeable quantities of non-protein nitrogen (NPN), as a replacement for true pro- tein, through the protein-synthesising ability of bacteria and protozoa in the rumen. These rumen microorganisms utilize ammonia (from break— down of true protein, or from NPN sources) and carbohydrates in the feed in the synthesis of their body protein. They in turn are digested by the host animal which utilizes the high quality bacterial and proto- zoal protein for its own metabolic functions. Low cost NPN compounds (mainly urea) are now widely used to re- place part of the true protein in ruminant rations. The use of urea as 1 an additive to elevate crude protein levels in corn silage rations, either at feeding or at ensiling time is well documented in the litera- ture. The addition of urea at ensiling time appears to be beneficial in that the urea is diluted through the silage, affording the animals a gradual intake which may help avoid palatability and toxicity problems associated with high concentrations of urea in the feed. Hatfield and Garrigus (1967), published a guide to urea and min- eral levels required for "balancing" corn silage, based on silage dry matter content at ensiling. The addition of NPN compounds to corn silage at ensiling increases the crude protein content (N x 6.25) of the final silage. Polan_g£.al. (1967) showed that the increase is proportional to the amount of NPN added. True protein degradation occurring during fermentation, results in decreased true protein content, and a corresponding increase in the water soluble NPN fraction composed of ammonia (product of deamination), alpha amino nitrogen (free amino acids) and other undetermined nitrogen com- pounds (Hawkins, 1969). Degradation of protein is greater at low dry matter levels of the silage (Hawkins, 1969, Geasler, 1970). Addition of NPN at ensiling increases the total NPN content of the silage; with urea additions, the increase is measured as ammonia (from urea breakdown) and unchanged urea (Bentley 35 El. 1955; Goodrich and Meiske, 1966; Polan £3 .31. 1967; Johnson g3 31. 1967). Increased true protein content of the silage may occur with NPN additions at ensiling, due to increased bac- terial protein as a result of the fermentation (Bentley 22 31. 1955; Modyanov_g£.§l. 1958; and Pesotskiy, 1963; Abgarowicz 25 a1. 1963). Organic acid content and final pH values are generally higher in 3 treated silages due to prolonged fermentation (Klosterman g£.§1. 1961 & 1962; Johnson 23.31. 1967; Huber £5 31. 1968). Apparent digestibility of dry matter, crude protein and crude fiber are enhanced by urea additions to corn silage at ensiling (Bentley .gg‘gl. 1955; Wetterau, 1959; Gorb and Lebedinsky, 1960; Johnson 33 El: 1965). In vitro studies indicate that rumen microorganisms can utilize various NPN compounds in the synthesis of protein, but to different de- grees, as indicated by bacterial growth. Urea is well utilized but am- monium salts of certain organic acids (lactic, succinic, and formic) appear to be preferred (Belasco, 1954). Palatability of urea-treated silage appears to decrease with in- creasing level of addition (Wise ggmal. 1944). Urea added at 0.5% ap- pears to have no affect on palatability in the majority of trials re- ported. Beef and Dairy cattle performance on urea-treated silages in most trials has equalled or surpassed performance on control silage plus true protein supplements (Bentley gg_al. 1955; Klosterman SE 51. 1961, 1962; Modyanov 23 31. 1963; Newland and Henderson, 1965; Huber SE 31° 1968; Henderson and Purser, 1968). The use of urea in corn silage is a widely accepted practice at this time, but the risk of incurring palatability problems and perhaps toxicity still exists and level of addition has to be strictly controll- ed. Other sources of nitrogen such as biuret (urea derivative), various inorganic ammonium salts, ammonia water and cyanuric acid have been added to corn silage to increase crude protein content in several experiments, but insufficient data are available to critically evaluate them. The use of anhydrous ammonia as an additive to corn silage at 4 ensiling has recently been tested at Michigan State University, primarily because of the lower cost of this material as compared to urea, and the consideration that much of the urea added at ensiling is broken down to ammonia in the silo anyway. A process was developed for the direct ap- plication of anhydrous ammonia to corn silage at ensiling by Henderson, Purser and Huber, 1969 (unpublished data). A liquid suspension of anhy- drous ammonia, minerals and molasses (Pro-Sil) was finally developed for safe and convenient application to the silage. The additive was formu- lated to correct for crude protein and mineral deficiencies in the final silage. The objective of the following study was to evaluate the effects of various levels of Pro-Sil added to corn silage at ensiling, on the following factors: a) corn silage fermentation, b) feedlot performance and feed costs of yearling steers, c) digestion parameters in steers. Regular corn silage and urea-treated corn silage were used as bases for comparison. II. LITERATURE REVIEW A considerable amount of recent research has been devoted to the use of chemical additives to corn silage at time of ensiling, the objec- tive being to increase total nitrogen content and thereby improve the nutritive value of the silage as a feed for ruminant animals. The addition of minerals to corn silage has received less atten- tion, however the entire area of additives to corn silage remains of prime interest to many animal researchers. Fermentation of Corn Silage One of the earliest reports on fermentation of the corn plant was that by Annett and Russell (1907). Chemical analyses of the corn plant before and after ensiling indicated that the principle changes occurring during fermentation were a decrease in nitrogen-free extract, an increase in non-protein nitrogen content with a corresponding decrease in protein nitrogen, a reduction in sugar content, and the appearance of fermenta- tion acids (volatile fatty acids (VFA) and lactic acid). Owens (1968) quoted work by Dox and Niedig (1912, 1913) and Niedig (1914) who reported the presence of ethanol as well as lactic acid and volatile fatty acids. Lactic acid content was usually greater than that of the VFA's, and total organic acid content maximized 8 to 10 days following ensiling. A thorough description of the various stages of fermentation and production patterns of VFA's (mainly acetic acid) and non-volatile acids (mainly lactic acid) from soluble carbohydrates is given by Barnett (1954). 6 A detailed study of the composition of corn plants at various stages of growth, including thorough chemical evaluation of the individual parts of the plant, was conducted by Benne 23 31. (1964). Johnson 33 31. (1966) compared soluble carbohydrate content of corn plant material before and after ensiling and found a large decrease due to ensiling. Most of the loss of soluble carbohydrate was recovered as lactic and acetic acids. Soluble carbohydrate content of the plant was shown to decrease with maturity. A highly significant correlation between soluble carbohydrate con- tent and organic acid content of corn silage was reported by Geasler (1970), it was also noted that increasing maturity of the corn plant ma- terial significantly reduced lactic acid content in the final silage. In the same study, total nitrogen in the silage as a percent of dry matter, decreased with maturity, as did water soluble nitrogen (expressed as a percent of total nitrogen). Hawkins (1969) working with alfalfa silage also reported a negative correlation between total organic acid produc- tion and silage dry matter content. Protein degradation during ensiling was increased with decreasing dry matter content, as measured by the in- crease in water soluble NPN (expressed as a percent of total silage nitro- gen). Early work by Russell (1908) indicated that the breakdown of pro- tein in maize silage fermentation was due to tryptic enzymes of the cell. This work was repeated by Kirsch in 1930 (as reported by Watson and Nash, 1960) using red clover, and confirmed the findings of Russell. Watson and Nash conclude from this and supportive evidence from Lamb (1917) and Hunter (1921) that plant enzymes are entirely responsible for the break- down of protein to amino acids, and that further changes (beyond amino 7 acids) are not necessarily due to plant enzymes but may also be caused by bacteria. Mineral constituents of plant material are affected during ensiling (Watson and Nash, 1960) but the changes take the form of recombinations and do not result in actual losses, except in so far as material is leached from the silo. There is a lack of information in the literature regarding mineral loss from silage. Effect of Silagg Additives on Silage Fermentation According to Owens 33 El. (1968), the earliest reported additions of NPN to corn silage were by Brigl and Windheuser (1932) and Windheuser _g£-§1. (1935) using urea, ammonium carbonate and ammonium bicarbonate as nitrogen sources. They reported increased lactic acid content of the silages and improved crude protein digestibility, but greater dry matter loss during fermentation with the addition. Cullison (1944) observed prolonged fermentation in regular sorghum silage, which was prevented by increasing the crude protein content by addition of 10 lbs. urea per ton of silage. He also reported improved palatability and general feeding value of the silage with the addition of urea at ensiling. Other work with sorghum silage (Davis 35 31. 1944) which compared various levels of urea at ensiling, indicated that the major part of the urea added re— mained as intact urea in the silo. Higher final pH in the treated silage over control silage indicated an extended fermentation due to buffering, especially with high urea levels. Urea additions (0.5% added) to corn silage by Woodward and Shephard (1944), did not reduce silage losses of dry matter, nitrogen and carotene, but little loss of urea occurred. Wise SE 31. (1944) added urea in aqueous solution (0.5% urea addition to silage) and reported increased 8 crude protein content and elevated pH of the final silage. Numerous re- ports in the literature show conclusively that additions of NPN compounds will increase crude protein content of silage and amount of increase is dependent on level of addition of NPN (Davis g£_§1. 1944; Bentley_g£.§l. 1955; Wetterau, 1959; Klosterman, 1961; and Schmutz, 1966). Silo losses of urea were extensively examined by Austin (1967) and negligible losses were reported. Russian workers (Modyanov SE 31. 1958) used various levels and mixtures of urea and ammonium sulfate as additions to corn silage at en— siling and reported increases in both total nitrogen and protein nitrogen levels. They recommended from their results that a 2:5 ratio of ammonium sulfate to urea should be used. Abgarowicz and co-workers in Germany (1963) used urea, ammonium sulfate and ammonia water additions to silages, and reported a greater increase in crude protein level (over control si- lage)with urea, followed by ammonium sulfate. Poor results were obtained with ammonia water which they concluded was due to weak bonding of the ammonia and to silo seepage. Increased acetic acid and final pH values but decreased lactic acid content were reported for all treated silages. An increase in true protein due to treatments, (highest increase due to ammonia water) confirmed the results of the previous study, (Modyanov SE .31. 1958). Further evidence of a true protein increase in treated silages was provided in a study by Pesotskiy, (1963) using ammonia water additions to corn silage. Additional increases were reported for NPN, ammonia, acetic acid, and pH, but lactic acid level was decreased as in the pre- vious study by Abgarowicz g£_al. 1963. Klosterman £5 £1. (1961) suggested that the high feeding value of corn silages might be due to their organic acid content and stated "It 9 was also found that the amount of acetic and lactic acids in these si- lages could be markedly increased by the addition of a neutralizing ' Limestone or urea and combinations material at the time of ensiling.’ of these two were used as additions to corn silage in a laboratory ex- periment by these workers which showed increased organic acid content for all treatments over a control silage. Highest levels of lactic and acetic acids were achieved with 0.5% urea + 0.5% limestone and 0.5% urea + 1% limestone combinations, and levels for these treatments were similar. In 1962 Klosterman fig 31. again reported increased lactic and acetic acid with urea-limestone additions. Johnson st 31. (1967) confirmed the previous findings using lime- stone-urea treated silage and reported that the amount of acids (lactic and acetic) produced, decreased as dry matter content of the silage in- creased. At low dry matter content (20% dry matter) of the silage, lac- tic acid was decreased and acetic acid increased with urea-limestone additions, which supports the findings of the EurOpean workers previously mentioned (Abgarowicz £5.2l' 1963 and Pesotskiy, 1963). In all other treated silages with higher dry matter content both lactic and acetic acids increased. True protein decreased in untreated silage as a result of fermentation, with a corresponding increase in soluble NPN, most of which was ammonia and urea, however part of the total was unidentified. In treated silages, increased proteolysis was reported for low dry matter silages but this effect decreased in silages of later maturity. Only a partial breakdown of urea occurred in the silage (35-63% breakdown), and the trend indicated less breakdown as maturity of silage increased. (Similar results were reported by Huber 25.31. 1968). Diammonium phos- phate (DAP) was also used in this study with similar trends reported but lo less organic acid produced. The authors postulated that much of the urea in silage may be hydrolysed and appear as ammonium salts. A study using miniature silos by Owens, Goodrich and Meiske (1966) also reported increased lactic and acetic acid production with urea addi- tions at ensiling, but in contrast to the results of Klosterman 35 El: (1961) no increase in lactic acid was obtained with limestone additions. However silage dry matter content was high in this study. In vivo evaluation of silage additives Bentley, Klosterman and Engle (1955) used wether lambs to compare digestion parameters for urea-treated silage and control silage (unsupple- mented and with soybean and corn-urea supplements). Apparent dry matter digestibility was similar for all rations, apparent crude protein digest- ibility was low for unsupplemented control silage but high for all other treatments indicating good utilization of urea whether added at ensiling or at feeding. Cellulose digestibility was higher for urea-treated si- 1age than for control silage with urea added at feeding. Nitrogen re- tention data showed that lambs on all treatments were essentially at ni- trogen equilibrium. Digestion studies by Wetterau (1959) using lambs, indicated that urea-treatment of silage (0.5% added) improved crude pro- tein digestibility and nitrogen retention compared to no treatment. As in the previous experiment, apparent dry matter digestibility was similar for treated and untreated silages. Gorb and Lebedinsky, 1960, (as report- ed by Owens, 1968) found slight increases in apparent digestibility of dry matter and crude protein for urea-treated silage as compared to con- trol silage when fed to lambs. Results were similar in a series of diges- tion trials conducted by Karr g£_§1, (1965) with lambs. Improved total nitrogen and digested nitrogen retained were reported using urea-treated 11 and biuret-treated silages as compared to adding urea or biuret to con- trol silage at feeding. Johnson 22.31: (1965) reported improved apparent dry matter diges- tibility of urea-limestone treated and DA? treated corn silages, using sheep. The BAP-limestone treatment depressed dry matter digestibility. Results of two digestion trials with sheep, reported by Schmutz (1966), revealed that urea-treated silages (0.5% and 1% urea added) and urea- limestone treated silage (0.5% urea + 0.5% CaCO3 added) slightly decreased dry matter, ash and crude protein digestibility coefficients and signifi- cantly decreased crude fiber digestibility. In vitro evaluation of silage additives A detailed in vitro study of nitrogen feed compounds for ruminants was conducted by Belasco (1954) using an artificial rumen described by Burroughs ggngl. (1950). The amount of bacterial growth on urea was used as a standard for comparing the value of other compounds. Urea deriva- tives (methylenediurea and biuret) gave poor bacterial growth, propion- amide gave good results (92% of urea reaponse). Some amidines gave good bacterial growth but not higher than urea. Greatest response was obtained with organic ammonium salts which demonstrated high availability of their nitrogen to the microflora. A high level of NH4+ ion was noted when they were introduced into the system. Belasco concluded that excess ammonium salts may not be as hazardous as excess urea because of the acid radical, which might enter into some biosynthetic process stimulatory to nitrogen fixation by the rumen microflora. Several organic ammonium salts, namely ammonium succinate, -lactate and -formate were utilized to a greater degree than urea. Free ammonia levels from inorganic ammonium salts were similar to those for urea. Ammonium nitrate was found to be toxic to the 12 microflora. Pearson and Smith (1943) found that rumen liquor could split urea and predicted very rapid conversion of urea to ammonia. They further con- cluded in a following experiment that protein was synthesized at the ex- pense of ammonia. In vivo and in vitro studies by Johnson and McClure (1964) using urea, biuret and DAP led them to conclude that urea was used more efficiently by sheep than biuret or DAP. The in vitro study demon- strated clearly that microorganisms from sheep "adapted" to biuret failed to release ammonia from biuret when incubated in vitro. Effect of Silage Additives on Beef and Dairy Cattle Performance Early reports on urea additions to corn silage mentioned impaired palatability of the silage but no effect on animal performance (Woodward & Shephard, 1944; Wise ES 31. 1944). Bentley 33 El: (1955) reported that treated silage compared favorably with control silage + soybean meal in a steer feeding trial. Later work at Ohio showed improved weight gains and feed efficiency with heifers fed urea-limestone treated silage (Klosterman SE El: 1961; Klosterman et a1. 1962). Performance was superior with treated silage at three levels of soybean meal supplementation and at var- ious concentrate levels as compared to control silage. The Russian workers, Modyanov £3 31. (1963) reported improved per- formance in cattle and sheep as measured by higher gains, greater milk production and greater feed intake when corn silage was treated with urea and ammonium sulfate compared to no treatment. Complete ensiled rations containing urea, promoted higher liveweight gains and greater efficiency in two beef feeding trials conducted by Goodrich and Meiske (1966), di- gestion trials with lambs suggested that crude fiber in the complete ration was more available. In a study with lactating dairy cows, Huber, .‘oll'h. blur! an? Ix N .I III : 13 Thomas and Emery (1968), found no difference in average production levels of cows fed urea treated silage as compared to untreated corn silage, but they did report a significant interaction between urea treatment and si— lage maturity, persistency of lactation was lower for cows on urea treat- ed high dry matter corn silage. The authors suggested that the high heat of fermentation could have rendered nitrogen unavailable. Newland and Henderson (1965) used beef heifers to examine effects of urea-limestone treatment of corn silage, and reported slightly higher gains, greater feed efficiency and cheaper gains as compared to lots receiving control silage. Henderson and Purser (1968) reported soybean oil meal supplementa- tion of corn silage at feeding to be superior to urea supplementation at ensiling or at feeding on all silage rations, as measured by rate of gain of beef heifer calves. However, feed costs favored urea fed calves. They further reported that addition of urea at ensiling was superior to sup- plying the same amount of urea at feeding. Daily dry matter consumption was similar for urea-treated silage and control ration, but reduced for groups receiving urea additions to silage at feeding time. In the same study, groups receiving a 1% concentrate addition to silage at feeding showed no differences between daily intake of urea-treated silage and control silage. Feed costs decreased as the level of urea in the ration increased. Recent studies at Michigan State by Henderson, Purser and Geasler (1969) comparing the addition of a liquid suspension of anhydrous ammonia, minerals and molasses (Pro-Sil) to corn silage at ensiling, with urea and urea + mineral additions, indicate that Pro-Sil and urea-mineral additions improved performance of steers as compared to urea addition alone. 14 Improved feed consumption was reported for steers fed Pro-Sil treated si- lage. Data from a later experiment (Henderson and Geasler, 1969) using rye silage treated with Pro-Sil and fed to yearling steers, shows im- proved gains and lower feed costs for steers fed the Pro—Sil treated silage over those fed control silage with a urea supplement at feeding. III. MATERIALS AND METHODS _E§periment I - Yearlipg Steer Feeding Trial Design: A 6 x 2 factorial (Appendix II, Table I) design was utilized to study the following treatments on yearling steers. A. Silage Treatments: B. l) 2) 3) 4) 5) 6) Negative Control Corn Silage - Silage not treated, mineral supple- ment fed but no protein supplement fed. Positive Control Corn Silage - Silage not treated, mineral and protein supplement (soybean oil meal) fed. Pro-Sil treated corn silage (10.5% Crude Proptein Equivalent) - Silage treated with Pro-Sil (protein and minerals) - no other pro- tein or mineral supplement fed. (Pro-Sil 10) Pro-Sil treated corn silage (12% Crude Protein Equivalent) - Same as #3 above but a higher level of Pro-Sil was added. (Pro-Sil 12) Pro-Sil treated corn silage (14% Crude protein equivalent) - Same as #4 above with a further increase in level of Pro-Sil added. (Pro-Sil l4) Urea-treated corn silage - silage treated with urea, mineral sup— plement fed but no protein supplement fed. All six silage treatments were compared at two levels of concentrate feeding: 1) Full feed of corn silage with no added shelled corn 15 l6 2) Full feed of a mixture of 60% corn silage and 40% rolled shelled corn on a dry matter basis (equivalent to 1% of bodyweight daily in shelled corn). Harvesting of Silages Control silage (received no additive) was harvested during the en- tire 15 day period from September 15 to September 30, 1969 and stored in a 9m. x 18m. concrete stave silo. Dry matter (DM) content of individual loads varied from 28.5% to 32.8% with an overall average of 30.5%. Silage treated with Pro-Sil was harvested during a seven day period from September 12 to September 19, and stored in three 4.8m. x 15m. con- crete stave silos. Different amounts of Pro-Sil were added in each silo; for Pro-Sil 10 silage the equivalent of 13.7 Kg. Pro-Sil per 1000 Kg. of 35% DM silage was added, for Pro-Sil 12 the addition was equivalent to 25 Kg. per 1000 Kg. of 35% DM silage and for Pro-Sil 14 the addition was equivalent to 35 Kg. per 1000 Kg. of 35% DM. The formulation of the Pro- Sil used in this experiment is shown in Table 1. Individual loads of silage treated with Pro-Sil varied from a low of 26.5% DM to a high of 31.5% DM. Pro-Sil 10 silage averaged 27.9% DM, Pro-Sil 12 silage averaged 29.9% DM and Pro-Sil l4 averaged 29.5% DM. The Pro-Sil was applied by pumping the required amount of the liquid ma- terial directly into the blower housing as each load of silage was being unloaded and blown into the silo (Figure I). Silage treated with urea was harvested over a three day period just prior to the other silages and was also stored in a 4.8m. x 15m. concrete stave silo. Individual loads varied from a low of 25.5% DM to a high of 32.5% DM and averaged 28.6% DM. Each load was weighed and treat- ed with an equivalent of 6.2 Kg. urea per 1000 Kg. of 35% DM silage, by 17 evenly spreading the required amount of urea over the top of each load just prior to ensiling. The formulation of the mineral supplement fed with urea-treated and control silages is shown in Table 2. This supplement was added at the rate of 5% of daily silage dry matter intake. The positive control group received soybean oil meal (50% crude protein) at a level equivalent to 2.1 Kg. per 20 Kg. of silage dry matter. l8 .oawm uoBOu a aw owuaum suou cu Hamloum wafihfianw aw cum: unusaH=vo mo aowuouunpaau afiumaucum .u museum ozaampoo uoHpo m>A<> m mo4<> mUms mopam> I m .n .o .m .< Ano.uvmv hauamuamacmwm upquo muaauomuoaam acouowmwv wca>ms mo=Hm> I n .m Aamwouuwz manoee< + cowouuaz puppy I zmz manpaom nouma I cowouuwz oocweuoumvcp \m Cowouuwz oaopHom nouns I cowouufiz Hmuoe I cowouuw: manpaomcfi woumz \N "oucmuwMficmfim eao< usuooe + efiu< canons u eso< uacmwpo Hmuoa \s uouum oumvcmum I .m .w \d mm. o.s N.s N.s H.s o.s ma sm.~ amm.o «mo.o~ ms~.o omo.w mso.m eag< assume so.~ msm.m pmm.~ Ems.m mmm.m use.m I. eau< usuooe oo.N < c mgm<8 EV. ”IIIIIH - J NITROGEN FRACTIONS AS A PERCENT OF DRY MATTER p—I 0 U1 I J— O I o O U! l 29 TOTAL NITROGEN WWI WATER INSOLUBLE N. 7/) WATER SOLUBLE N.P.N. 4 H1- [1% \\\\\\\\\L \\\\\\\l \\\\\\\\\\\\\I / . / / \ \\\\\\\\\\I FIGURE 2. CONTRO PRO-SIL 10 PRO-SIL 12 PRO-SIL 14 Mean total nitrogen, water insoluble nitrogen and water soluble NPN concentrations, as % of DM (Expt. 1) E 30 (P¢<.05) probability. Other differences in water insoluble nitrogen were not significant. These increases appear to indicate an increase in true protein content of silages which were treated with ammonia and urea, and this protein increase must be due to increased bacterial protein, or decreased proteolysis during fermentation. These results agree with results of Modyanov g; 31. 1958; Abgarowicz 25 a1. 1963; Pesotskiy, 1963. Analysis for water soluble protein revealed only trace amounts in a few instances, however, no measurable amounts were present. Water soluble NPN (Figure 3) varied with level of NPN added to the silages, Pro-Sil 12, Pro-Sil 14 and urea silages were significantly higher (P< .01) than Pro-Sil 10 and the control silages. The chemical analysis of the constituents of the water soluble fraction of the silages revealed only very low amounts of ammonia and urea nitrogen present in the control, 79% of the nitrogen was in the form of unidentified compounds. In all of the Pro-Sil treated silages the increase in water soluble NPN over control silage was mainly in the form of ammonia nitrogen with some increase in unidentified nitrogen com- pounds. In the urea-treated silage the increase in ammonia nitrogen was less and a considerable amount of urea was found intact (58% of total urea added). Differences in ammonia nitrogen were significant (P<.05) for Pro-Sil 14 over Pro-Sil 12 and highly significant (P<.01) for Pro-Sil 14 over all other silages. The slight difference between Pro-Sil 12 and Pro-Sil 10 was not significant but values for both were significantly (P<.01) higher than those for urea-treated and control silages. The urea silage contained significantly (P<.01) higher amounts of urea nitro- gen than all other silages. Differences in unidentified nitrogen levels were not significant due to the accumulated error involved in the mwfiuj.a_ I- , WATER SOLUBLE NPN AS A PERCENT OF DRY MATTER 31 DD UNIDENTIFIED NITROGEN UREA NITROGEN 1.1. D AMMONIA NITROGEN ——-I 1.0- fl -—'1 0.9- 0.8- 0.7.. 0.6.. 0.5- :na: 0.4- -——I W. / xi: *1 4 m a 0.2- 0.1- CONTROL PRO-SIL 10 PRO-SIL 12 PRO-SIL 14 UREA FIGURE 3. Mean total water soluble NPN (as % of DM) of silages, showing actual urea and ammonia fractions (Expt. 1). 32 calculations. These finds, in regard to urea breakdown, agree with other work (Johnson ggflal. 1967; Huber ggnal. 1968), and the increase in ammonia with increased Pro-Sil addition is as expected, the ammonia presumably being in the form of ammonium salts of organic acids (Klosterman SE 31. 1961). giganic acids: Total organic acid fraction (as a percent of dry matter) was cal- culated by combining total acetic and lactic acid values, as the amounts of other organic acids are extremely small and consequently are not pre- sented. All treated silages showed large and highly significant (P<.01) increases in total organic acid as compared to control silage (Figure 4). Differences between treated silages were not significant, but Pro-Sil treated silages tended to have higher values, indicating a greater neutral- izing affect for the ammonia additions. Acetic acid production was sig- nificantly (P4{.05) depressed for Pro-Sil 12 and Pro-Sil 14 silages and slightly increased for the urea treated silage. Lactic acid levels were increased considerably in all of the treated silages. Greatest increases were evident in the Pro-Sil treated silages, and level of organic acid appeared to be directly related to the amount of Pro-Sil added to the si- lage. Differences between Pro-Sil treated and urea treated silages were not significant however, but lactic acid levels for all treated silages were significantly greater (P<.01) than in the control silage. It appears that the neutralizing effects of ammonia and urea pro- longed the lactic acid fermentation in all silages, and adversely affected acetic acid production in Pro-Sil 12 and Pro-Sil 14 silages. The lowered acetic acid levels were unexpected and cannot be explained at this time. HI F _I/// /// /////////. 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