'I‘HE CHEMISTRY, QACTEREGKOGY. AN? NUTRITWfi VALUE OF ENSiLEE filGHMOISTEfiRE GRGUND EAR CORN Thai: for the bags“ af M. 5-. MECHIGAN S‘MTB UNIVERSETY Wifléam G. Swahmufz E962 H \; 17171111711171 7771 71111111171 1, LIBRARY” '" Michigan Stité Universny ”" ' PLACE IN RETURN BOX to remove 1N0 checkout from your record. TO AVOID FINES return on Of befom due due. DATE DUE DATE DUE DATE DUE - yell I 185191 71992' " 1 "‘ 11 MSU Is An Affirmative Action/Equal Opponunlty Institution emana-pd THE CHEMISTRY, BACTERIOLOGY, AND NUTRITIVE VALUE OF ENSILED HIGH-MOISTURE GROUND EAR CORN By William G. Schmutz AN ABSTRACT OF A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Dairy 1962 ABSTRACT THE CHEMISTRY, BACTERICLOGY, AND NUTRITIVE VALUE OF ENSILED HIGH-MOISTURE GROUND EAR CORN by William G. Schmutz During a two-year period, ground ear corn at vary- ing moisture levels was ensiled with the addition of dif- ferent compounds. Ammonical-N, urea, pH, organic acids, ethyl alcohol, and crude protein were determined over a 60-day fermentation period. The total counts, lacto- bacilli, yeasts, molds, and anaerobic counts were followed using six silages. Temperature studies were included in one study. Following the 60-day fermentation period, the si- lages were fed to growing dairy heifers. Weight gains, feed fed, and rejections were recorded on each heifer. Correlation analysis was conducted using the silage qual- ity measurements and animal performance data. Silages with 20 pounds of urea per ton increased in pH throughout the fermentation period. With 15 pounds of urea per ton, this effect was not noted. The silages containing 20, 15, and 0 pounds of added urea had an initial pH of 4.7, 6.0, and 6.5; but following 60 days fermentation the pH had changed to 7.4, 5.1, and 5.2. In William G. Schmutz a second trial there was a depression (P < 0.01) of pH with high moisture and with the addition of one percent monobasic calcium phosphate. In a third trial, 40 and 54 percent moisture silages depressed the pH (P < 0.01) as compared with 24 percent moisture silages. There was no direct pattern for butyric and propi- onic acid production in individual silos; but there was a tendency for more butyric and propionic acid production in the higher moisture silages (54-45% moisture). One percent monobasic calcium phosphate reduced the concen- tration of these two acids at higher moisture levels. In all three trials, acetic and lactic acids were signifi- cantly higher at the higher moisture levels. Lactic acid increased and acetic acid decreased with the addition of one percent monobasic calcium phosphate. In general, 50 percent of the urea was broken down within 20 days and 80 percent within 60 days. Monobasic calcium phosphate depressed (P < 0.01) the rate of break- down of urea in one of two trials. There was an increase (P ‘ 0.01) in crude protein with additions of 20 pounds of urea. In two trials there was a slight increase (P < .25, P < .25) in crude protein with the higher mois- ture silages. This effect was not noted in a third trial. William G. Schmutz The ethyl alcohol content of the silages was in- creased in the higher moisture silages. The average con- tent was 0.2 percent. The total microbial counts were within the same log range for 40, 54, and 24 percent moisture silages. The mean log counts of Lactobacilli from the 45- and 60- day samples for 40, 54, and 24 percent moisture silage were 8.5, 8.6, and 7.9, respectively. Yeast counts in- creased and anaerobe counts decreased with decreasing moisture. With the exception of one growth study, there were no significant differences in weight gains when ensiled ground ear corn (24-45%:moisture) was compared to ground dry corn. One percent monobasic calcium phosphate in- creased gains by 19 percent. In two growth studies, ani- mals fed the wetter silages (54-45% moisture) required less (P < 0.05, P < 0.25) dry matter per pound of gain. Similarly heifers fed the wetter silages consumed less (P * 0.01) dry matter per day than heifers fed the drier silages. Correlation coefficients between average daily gain and silage quality measurements showed a negative correlation with 50-day acetic acid, 10-day pH, and 60-day William G. Schmutz pH, and a positive correlation with 60-day lactic acid. Fermentation losses in the silage averaged three to six percent regardless of the moisture level. THE CHEMISTRY, BACTERIOLOGY, AND NUTRITIVE VALUE OF ENSILED HIGH-MOISTURE GROUND EAR CORN By William G. Schmutz A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of EASTER OF SCIENCE Department of Dairy 1962 ACKNOWLEDGEMENTS The author expresses sincere appreciation to Dr. R. S. Emery, Associate Professor of the Department of Dairy, for his many hours of timely counsel during the course of this study and for his critical reading of the manuscript and to Dr. L. D. Brown, Assistant Professor of the Department of Dairy, for his gracious assistance at the initiation of the study. The author also expresses appreciation to Mrs. Dorothy Carpenter, Dairy Laboratory Technician, to Dr. E. J. Benne, Professor of the Department of Biochemistry, who performed a portion of the chemical analyses on the silage samples, and to Mr. Dennis Armstrong, who managed the experimental animals. The author is especially grateful to his wife Betty for her loving faith and encouragement during the course of this study. ii TABLE OF CONTENTS INTRODUCTION . . . . . . REVIEW OF LITERATURE . . Nutritive Value of High-Moisture vs. Low- Moisture Corn in Different Species. Beef Cattle. . Sheep. . . . . Swine. . . . Dairy Cattle . Urea, Calcium Carbonate, Calcium Phosphate, and Phosphoric Acid as Silage Additives: Nutritive Value of Additives in Silage. I. Urea: Nitrogen Sources. II. The Value of Urea in Silage . III. bonate. . . IV. Silage Fermentation: The Chemistry and Bac- Phosphoric Acid . teriology of Different Types of Silage. Acid Production. Bacterial Populations and Sequences in Silages . . Yeasts . . . Heat Production. EXPERIMENTAL PROCEDURE . Trial I . . . . . . Trial II. . . . . . Trial III . . . . . Chemical Analyses . Moisture, pH, Ammonical NitrOgen, Crude Protein . . iii Calcium Phosphate and Calcium Car- 0 The The Utilization of Non-Protein Page 11 15 14 19 2O 24 27 28 50 51 33 57 57 41 41 45 47 47 TABLE OF CONTENTS (Continued) Urea Determinations. . Volatile Fatty Acids . . . . . . Ethyl Alcohol. . . . . . . . . . Bacteriological Procedures. . . . . . RESULTS. 0 0 O O O O O O O O O 0 O O 0 0 0 Chemical and Bacteriological Studies. pH . . . . . . . Organic Acids. . Urea . . . . . . Crude Protein. . Ethyl Alcohol. . Bacterial Counts . Silage Temperatures. Animal Performance . Weight Gains. . . . . . . . Feed Efficiency . . . . . . Feed Intake . . . . . . . . Correlations Between Animal Performance and Silage Quality Measurements . Acreage Yields--Fermentation Loss. . . DI SCUSSION O O O O O O O O O O O O O O O O SMIARY. O O O O O O O O O O C O C O O O 0 LI TERATURE C I TED O O O O O O O O O O O O 0 iv Page 48 49 49 50 54 57 61 65 66 67 69 69 71 72 72 72 75 83 86 TABLE II III IV VI VII VIII IX XI XII LIST OF TABLES pH of Far Corn Silage . . . . . . . . . . Butyric and Propionic Acids . . . . . . . Effect of Moisture on Organic Acid Pro- duction. . . . . . . . . . . . . . . . Effect of Time on Urea Content (Mean Values for All Silos with Urea). . . . Effect of Moisture and Urea on Protein COnt ent O O O O O O O O O O O 0 O O O 0 Mean Ethanol Content of Ear Corn Silages. Logarithm Microbial Counts. . . . . . . . Results of High-Moisture Corn Feeding Trials 0 O O O O O O O O O O O O O O 0 Effect of Monobasic Calcium Phosphate on weight Gains O O O O O O O O O O O O 0 Correlation Coefficients Between Average Daily Gain and Chemical Composition. . The Effect of Moisture on Yield per Acre. Losses in High-Moisture Ground Ear Corn . Page 55 59 6O 61 65 67 7O 71 75 75 74 FIGURE LIST OF FIGURES The pH of High-Moisture Ear Corn Silage with Different Levels of Urea. . . . The pH of High-Moisture Ear Corn Silage at Different Levels of Moisture. . . The Presence of Urea in High-Moisture Ear Corn Silage During a 60-Day Fer- mentation Period . . . . . . . . . . The Effect of Moisture on Temperature (Trial III). 0 o o o o o o o o o o 0 vi Page 56 58 62 68 INTRODUCTION One of the big problems facing the corn grower and the livestock feeder is harvesting his crOp. In the corn belt states and especially in the northern sections of the country, the weather interferes with the corn harvest. A method for preserving the nutritive value of corn when harvested before full maturity is needed. This can be accomplished by artificial drying; however, the cost is prohibitive. In the last five to ten years, experimental work has been undertaken at several state universities and experiment stations on the ensiling of high-moisture corn as a method of harvesting and storing. The follow- ing advantages have been given: (1) Corn may be stored even though the moisture is too high for cribbing; (2) Corn may be harvested at the convenience of the farmer; (5) Increased yields may be obtained due to less shatter- ing during harvesting. Similar advantages that could be stated are a minimum of Operations and equipment, lower cost, rodent free storage, simplified mechanical feeding, and if moist corn is utilized, it permits timely cultiva- tion of the soil for the ensuing crop. The previous work dealing with high-moisture corn has been mainly on the nutritive value of this fermented product as it pertains to the feeding of beef cattle, sheep, swine, and to a lesser extent, dairy cattle. Only a small fragment of the work has dealt with the actual fermentation processes which ear corn undergoes when it is ensiled. The data presented in this manuscript deal with some of the chemical processes and transformations that occur in this ensiled product along with some of the bacterial populations and species that are present in the silage. Finally, data will be presented on feeding trials to illustrate the nutritive value of the ensiled product. REVIEW OF LITERATURE It was stated in the introduction that a large vol- ume of the experimental work dealing with high-moisture corn concerns the nutritive value of this product when fed to species of animals other than dairy cattle. Few studies have included chemical or bacteriological data on the ensiled product. Most of these studies have in- cluded additives in the silages such as calcium carbonate, limestone, tetraalkylammonium stearate, yeasts, and 5- nitro-4-hydroxyphenylarsonic acid. From this collection of data much has been learned. Nutritive Value of High-Moisture vs. Low-Moisture Corn in Different Species High-moisture corn has been utilized to the greatest extent by the portion of farmers that deal mainly in a meat product since the consumption of corn normally leads to an increase in body fat. Since this is the case, a large volume of the work is from experiments using animals normally used for meat and meat products. Beef Cattle Most of the research on high moisture corn has been done in the past five to ten years. However, Rusk and Snapp (1924) were possibly the very first to see the value of harvesting and storing soft corn as an ensiled 5 product. ”Starting as early as 1916, they conducted six experiments involving the use of ear corn silage. In all but one of these six experiments, the cattle made satis- factory gains on all forms of soft corn. The most exten- sive study was consummated in the fall of 1924 when the Illinois experiment station fed four forms of soft corn, namely: shocked corn, standing corn pastured in the field, broken ear corn (mature corn), and ear corn silage. The soft corn ranged in moisture from 57 to 45 percent. .Since the 80-day experiment was to be conducted under adverse weather conditions, 72 western-bred Hereford steers weighing approximately 1,000 pounds each were used. Alfalfa hay and linseed meal were included in the rations. One group fed ear corn silage also received cats. The authors report that while satisfactory gains were made by all lots of cattle, the mature corn produced the most rapid gains. They felt that this difference was due to a larger consumption of dry matter rather than to any dif- ference in the quality of the dry matter. When the corn was calculated on an equivalent moisture basis, the cat- tle fed soft corn made the best showing with the exception of the ones fed soft corn standing in the field. Further, Rusk and Snapp (1924) reported that the largest gains produced per acre were made by steers receiving ear corn silage, leading them to conclude that the use of ear corn silage is the most economical method of utilizing soft mnxn Hansen gt 3;. (1959a, b) fed beef cattle high- moisture shelled corn stored at 24, 29, and 56 percent moisture with a control group receiving corn at 14.5 per- cent moisture. Using 44 yearling beef heifers, results showed that the corn at 24 and 29 percent was equal to dry corn in feeding value. Heifers fed 56 percent mois- ture shelled corn consumed about two pounds less (14.5 percent moisture basis) per day thus resulting in slower and less efficient gains. The feed per one hundred pounds of weight gain for the 18, 24, 29, and 56 percent moisture shelled corn groups were 686, 684, 681, and 740 pounds, respectively, while the average daily gains for these groups were 1.89, 1.90, 1.91, and 1.51 pounds per day, respectively. Beeson (1958) compared ground ear corn at 52 per- cent moisture and 18 percent moisture dry corn in the first of two feeding trials and ground ear corn at 55 percent moisture and 16 percent moisture dry corn in his second feeding trial using steers and heifers. In his first trial, four groups of ten steers averaging 952 pounds were used. Two groups were given 100 mg. of Terramycin in their rations daily. The average daily gains for the two groups receiving dry corn and those re- ceiving high-moisture corn were 2.54 and 2.52 pounds per day, respectively. This difference was not statistically significant. There was a 12 to 15 percent savings in pounds of corn per pound of gain for those steers receiv- ing high-moisture corn. In the second trial there was no significant difference in daily gains; but the heifers fed high-moisture corn required 10 percent less corn to produce a pound of gain. Beeson (1958) also feund that the daily dry matter consumption of ground ear corn silage' was less than dry corn. Klosterman 23 Q1. (1961a) attempted to increase the organic acid content in ear corn silage by adding 1.0 per- cent high calcium, ground limestone, and water to alter- nating loads of corn. Untreated ear corn was ensiled in the same silo using a plastic sheet to separate the in- dividual silages. These two silages were fed to nine groups of seven Hereford steers randomly assigned into weight groups. Three lots were fed the limestone-water treated high-moisture ear corn silage, three lots the untreated high-moisture corn silage, and three lots the dry corn. All lots were fed salt and minerals, good quality clover-timothy mixed hay and soybean oil meal. The corn was full-fed according to appetite. During the 224-day trial, the average daily gains for the treated ear corn silage groups, the control ear corn silage groups, and the dry corn groups were 2.07, 1.81, and 1.88 pounds per day, respectively. When the three forms of corn were 7 converted to an equal dry matter basis, each group of ani- mals consumed an average of 10.2, 9.7, and 11.2 pounds per day, respectively. Therefore, the steers fed the treated ear corn silage required less feed per unit of gain. These results were in general agreement with the results of Beeson (1958). Klosterman gt g1. (1961b) compared high-moisture ground ear corn treated with 0.5 percent high calcium ground limestone, 0.5 percent urea,and additional water to yield a moisture content of 48 percent, with untreated ear corn silage at 45 percent moisture. Soybean oil meal at two levels, 0.75 and 1.5 pounds, were fed with the treated and untreated silages. The daily gain of steers fed the treated silage was 0.12 pounds more per head than the cattle fed the untreated silage in a 195-day feeding trial. When the two levels of soybean oil meal were con- sidered, the two groups of steers receiving the treated silage plus 0.75 pounds of soybean oil meal gained an average of 2.2 pounds per day while the steers fed the control silage plus 0.75 pound of soybean oil meal aver- aged 2.0 pounds per day. When 1.5 pounds of soybean oil meal was fed with the treated and control silages, there was little difference in the average daily gains for the four groups which were 2.06, 2.15, 2.12, and 2.05 pounds per day, respectively. The author felt that the results 8 indicated that additions of urea, limestone, and water to ear corn silage increased the organic acids in the silage, and that urea may replace a part of the protein supplement needed. Beeson 23 Q1. (1958) also studied the use of plant proteins and urea in feeding experiments with high- and low- moisture corn. Linseed meal and soybean meal were used as sources of protein in the "Purdue Supplement A." Five percent urea was also studied as a replacement in the sup- plement. They reported that beef heifers fed regular crib corn at 24 percent moisture gained slightly more than heifers fed ensiled high-moisture corn at 57 percent mois- ture, though the differences were not significant. On an equivalent moisture basis, the heifers on the ensiled high-moisture corn required 4 percent less feed per unit gain and consumed 1.0 pound less per head daily. The sub- stitution of linseed meal for an equivalent amount of soybean meal did not give a consistent effect on rate of gain, while the substitution of 5 percent urea for either soybean or linseed meal on an equivalent basis resulted in gains equal to soybean or linseed meal as the principal source of protein in the supplement. In this study, urea was not a direct additive in the silage, but was fed with the silages, thus increasing its utilization as a protein source since there was no chance of its degradation in the fermentation processes. Van Arsdell gt g1. (1955) reports similar results when corn silage was supplemented with soybean oil meal and urea. Supplemental protein sources have not been the only compounds used to increase the value of high-moisture corn. Stilbestrol, "Dynafac" (20 percent tetra alkylam- monium stearate plus 80 percent bone meal), "5-nitro" (4- hydroxyphenylarsonic acid), antibiotics, and Torula yeast have been fed with high-moisture corn to study their bac- tericidal and gain-stimulating prOperties. Culbertson gt a1. (1957) used seventy-two BOO-pound yearling steers in a 119-day study to determine the nu- tritive value of high-moisture corn. Six pens of six steers each received full feed of low-moisture (14.5 per- cent) corn, and six pens received a full feed of high- moisture (51 percent) ground ear corn. In addition, the steers received 5 pounds of alfalfa hay and one pound of supplement per animal daily. The supplement varied only with respect to the presence or absence of Stilbestrol, "Dynafac," and "5-Nitro." The feeding results showed that the six lots of cattle receiving high-moisture corn made almost as much daily gain on 10 percent less corn (14 per- cent moisture basis) as the six similar lots of cattle receiving low-moisture corn. The average daily gains for the low-moisture and high-moisture groups were 5.05 and 10 2.98 pounds per day, respectively, while the total feed per 100 pounds gain on a 14 percent moisture basis was 889 and 819 pounds, respectively. This resulted in an 8 percent savings in feed costs in favor of high-moisture corn. High-moisture corn plus Stilbestrol resulted in a savings of 16 percent in feed costs. "Dynafac" and "5- Nitro" failed to stimulate live-weight gains or reduce feed costs. Beeson gt g1. (1957) in an experiment closely re- lated to that of Culbertson gt g1. (1957) compared high- moisture (52.5 percent) and low-moisture (15.5 percent) corn with additions of 0.10 pound of Torula yeast and one gram of "Dynafac" per heifer per day. "Purdue Supplement A," hay, and minerals were fed. "Dynafac" and Torula yeast did not significantly increase daily gains, but the 52.5 percent moisture corn improved feed efficiency when fed in addition to the "Dynafac". When "Dynafac" was fed with low-moisture corn, the reverse was true. It was also shown that on the same moisture basis the heifers on the 52.5 percent moisture corn required 10 percent less corn and consumed less dry matter to produce a pound of gain. These results are in general agreement with the results of (Culbertson gt g1., 1957; Beeson, 1958; and Klosterman gt g1., 1961a). Further information on the nutritive value of high- moisture corn has been gained with the use of antibiotics 11 (Beeson gt g1., 1956). Terramycin was fed with 52 percent moisture corn and regular dry corn at 18 percent moisture in a study to analyze the nutritive value of these three. The steers fed the high moisture corn gained somewhat faster (0.15 to 0.25 pounds per day); but this increase was not significant. Also, these cattle required 12 to 15 percent less corn to produce a pound of gain. Terra- mycin did not improve the daily gains or feed efficiency on these high energy rations. asses Cline g_ _1. (1960) used dry matter digestibility and nitrogen retention to measure the feeding value of high-moisture ground ear corn as compared to high-mois- ture shelled corn and field-dried shelled corn. An equivalent amount of cobs was added to the latter two forms of corn. These rations were fed to three groups of lambs (Hampshire-Suffolk X Western) averaging 85 pounds with each ration containing the same dry matter content. The apparent digestion coefficients in dry matter, per- cent nitrogen, and in nitrogen retention were lowest for the three groups of lambs on the high-moisture ground ear corn. The lambs fed the field-dried shelled corn were the high group, and the ensiled shelled corn group was intermediate. There was no significant difference 12 in the apparent digestibility and nitrogen retention among the lambs receiving the field-dried shelled corn and those receiving ensiled high-moisture shelled corn. Hansen gt g1. (1959a, b) found similar results with shellai corn stored at different moisture levels. Benjamin and Jordan (1960), also using feeder lambs, conducted three trials in which shelled corn and ground ear corn were stored using three methods of stor- age: (1) ensiling, (2) drying and ensiling, (5) drying only. When these products were fed to 175 feeder lambs, neither the shelled corn nor the ground ear corn, when ensiled, increased in nutritive value for feeder lambs. Gains were less with the ear corn ration than with the shelled corn ration. It was also reported that within a main treatment neither drying nor ensiling was found to have a significant effect on average daily gains, and en- siling corn which had been previously dried and then re-wetted to 55 percent moisture did not cause a signifi- cant change in the nutritive value. In a current report from the Missouri Agricultural Experiment Station, Ross and Rea (1959) used 64 ewe and 56 wether lambs in comparing the feeding value and yield of corn from the same field when harvested at 27.5 per- cent and 15.5 percent moisture. There were no signifi- cant differences in gains of the lambs fed high moisture or dry corn, but the wethers on the 27.5 percent moisture 12 in the apparent digestibility and nitrogen retention among the lambs receiving the field-dried shelled corn and those receiving ensiled high-moisture shelled corn. Hansen gt g1. (1959a, b) found similar results with shelled corn stored at different moisture levels. Benjamin and Jordan (1960), also using feeder lambs, conducted three trials in which shelled corn and ground ear corn were stored using three methods of stor- age: (1) ensiling, (2) drying and ensiling, (5) drying only. When these products were fed to 175 feeder lambs, neither the shelled corn nor the ground ear corn, when ensiled, increased in nutritive value for feeder lambs. Gains were less with the ear corn ration than with the shelled corn ration. It was also reported that within a ‘ main treatment neither drying nor ensiling was found to have a significant effect on average daily gains, and en- siling corn which had been previously dried and then re-wetted to 55 Percent moisture did not cause a signifi- cant change in the nutritive value. In a current report from the Missouri Agricultural Experiment Station, Ross and Rea (1959) used 64 ewe and 56 wether lambs in comparing the feeding value and yield of corn from the same field when harvested at 27.5 per- cent and 15.5 percent moisture. There were no signifi- cant differences in gains of the lambs fed high moisture or dry corn, but the wethers on the 27.5 percent moisture 15 corn made somewhat greater and more efficient gains than those on the dry corn. The average daily gains for the wethers on dry corn and high-moisture corn were .64 and .69 pounds per day, respectively; while the ewes aver- aged .66 and .59 pounds per day, respectively. The feed per pound of weight gain on a dry matter basis for wethers on dry corn and for those on high-moisture corn were 659 and 555 pounds, respectively; while for ewes the figures were 549 and 605 pounds, respectively. The authors felt that when their data were pooled and on an equivalent moisture basis, there was a savings in pounds of feed per pound of gain in favor of the lambs fed high- moisture corn. This statement was true for wethers; but more research should be done with ewe lambs to verify this point. suns Beeson and Conrad (1958) fed low-moisture shelled corn (12 to 19 percent moisture) and ensiled high-moisture shelled corn (26 to 52 percent moisture) to Duroc wean- ling pigs averaging 52 to 40 pounds. In two of the three feeding trials, pigs fed the high-moisture shelled corn gained from 5.0 to 4.9 percent faster but required 8 per- cent more feed on an equivalent moisture basis per 100 pounds of gain than pigs fed low-moisture shelled corn. In the third trial, both low- and high-moisture corn 14 groups gained the same, but after 70 days on experiment, the high-moisture corn fed pigs had required 14 percent more corn on an equivalent moisture basis. The authors concluded that there was no improvement in the nutritional value of the corn from ensiling it at a higher moisture. Hansen gt g1. (1959a, b) fed shelled corn at 25, 50, and 55 percent moisture to swine and found that the three moisture levels were inferior to dry corn. Dairy Cattle Zogg gt g1. (1961) compared shelled corn harvested at 22, 26, and 52 percent moisture in various combinations with oat, corn, and sorghum silages. Nine Brown Swiss and 18 Holstein cows were used in a combination split- plot and switch-back design. There were no significant differences between cows of varying productive capacity in the amount of dry matter consumed, but when grouped according to the silage fed, the cows fed oat silage consumed less dry matter than did the cows on either corn or sorghum silage. This relationship held true when the cows were fed silages with rations containing 22, 26, and 52 percent moisture corn. Generally, the cattle on the 52 percent moisture corn started at a lower rate of milk production, but their persistency was greater throughout the trial. The average decline in F.C.M. (4 percent fat-corrected milk) per cow during the 15 5-week experimental period for the 52, 26, and 22 percent high-moisture corn was ll, 15, and 16 pounds, respectively. When the entire 21-week trial was considered, the F.C.M. production for the 22, 26, and 52 percent moisture corn groups was 801.1, 858.5, and 871.9 pounds per day, re- spectively; while the weight changes for these groups were -54, -56, and +5 pounds per cow per period. Hansen gt g1. (1959a, b), in a similar study, presented results stating that shelled corn at 25, 50, and 55 percent moisture was not superior to dry corn for milk production. Lassiter gt g1. (1960) stored high-moisture corn grain and ear corn in a two-year study. In 1957 ground shelled corn was stored at 26 and 40 percent moisture and ear corn at 56 percent moisture. In 1958, ground ear corn, ground shelled corn, and unground shelled corn were stored at 52 percent moisture. The corn was harvested at 40 percent moisture and dried to the desired moisture level before grinding. Dried corn, used as a control, was dried to 14 percent moisture. When these forms of high-moisture corn were fed to milking cows, the performance of all groups was quite satisfactory, and the feeding value of the high-moisture corn was comparable to that of dry corn. In 1957, the high-moisture and dry corn gave better results than the 40 percent ground shelled corn. The cows on the shelled l6 corn produced less total 4 percent F.C.M. and showed a greater decline in 4 percent F.C.M. as well as less gain in body weight. From these results, the authors con- cluded that based on a dry matter content, the feeding value of the soft corn appeared to be equal to, but not greater than, that of dry corn. These results on nutri- tive value for milk production and weight gains corres- pond to the results of Zogg gt g1. (1961) who found a greater nutritive value for 26 and 52 percent moisture shelled corn than for lower moisture soft corn. Hansen gt g1. (1959a) stored shelled corn at 25, 50, and 55 Percent moisture when 24 Holstein heifers were studied. Corn at 14.0 percent moisture was used as a control group. The average daily gain and feed effi- ciency (pounds of D.M. per pound of gain) for the 14, 25, 50, and 55 percent moisture corn groups were 1.66, 1.57, 1.49, and 1.44 pounds per day and 8.7, 10.5, 9.7, and 9.9 pounds of dry matter per pound of gain, respectively. The authors felt that the growth response obtained from these heifers did not indicate that high-moisture shelled corn was superior in feeding value to regular dry corn. In another report, Hansen gt g1. (1959b), simi- lar conclusions were presented. The studies of Zogg gt g1. (1961) and Lassiter gt g1. (1960) represent the only studies in which any form 17 of high-moisture corn was fed to lactating dairy animals. The studies of Pratt and Rogers (1956) are concerned with the nutritive value of high-moisture corn when fed to growing dairy heifers. Corn ensiled at 54 percent dry matter and containing 5.1 percent protein was used in three different feeding trials. In their first trial eight Jerseys averaging about 750 pounds were fed mixed hay, grass-legume silage, and six pounds of ear corn si- lage. During a 12-week trial these heifers gained 1.12 pounds per day. In their second trial, seven yearling Holsteins and Jerseys averaging 765 pounds were fed 5 pounds of ear corn silage plus grass silage, soybean oil meal, and hay to appetite for 129 days. A control group was fed similarly except they received 5 pounds of grain equal in dry matter content to the 5 pounds of ear corn silage. The heifers on the ear corn silage gained as much as the control group in this trial. Similar re- sults were obtained in a third trial. One report by Cabell gt g1. (1962) was found in whnfli rats were used. Nine different types of high-moisture corn from four farms located in the corn belt were taken representing three types of silos: (1) gas tight, (2) concrete stave, (5) wood stave. A good sample and a poor sample were taken from each silo and dried for 24 hours. The dried samples were ground and mixed into diets 18 . containing equal amounts of nitrogen. Weanling rats were fed the diets in a 21-day assay test. The mean weight gain for rats on a crib-dried control corn was 72.4 grams as compared to 75.8, 75.6, and 78.4 grams for good samples of high-moisture corn from gas tight, concrete stave, and wood stave silos, respectively. There was no significant loss from the different types of silos. The poor samples all produced lower weight gains than the corresponding good samples; and the poor sample from the gas tight silo was significantly lower. In all the studies with beef cattle, the rate of gain was not significantly greater for either high- or low-moisture corn; but it has been clearly brought out by Beeson gt g1. (1956), Beeson gt g1. (1957), Culbertson gt g1. (1957), Beeson gt g1. (1958), Beeson (1958), and Klosterman gt g1. (1961a) that cattle require from 4 to 15 percent less feed per unit of gain when fed high- moisture corn. Studies with sheep show similar results. With swine, gains are somewhat variable but in all cases less efficient with high-moisture shelled corn. Lactat- ing dairy cows appear to make efficient use of high- moisture corn ; and a moisture range of 25-55 percent is the optimum range for production. Dairy heifers gain equally well when fed high-moisture corn or dry corn. l9 Urea, Calcium Carbonate, Calcium Phosphate, and Phosphoric Acid as Silage Additives: The Nutritive Value of Additives in Silage Urea Urea as a protein sparing agent in livestock feeds has been studied by a multitude of researchers. Since the addition of urea to soft corn silage is a minor subject in this thesis, a short review of the more pertinent stu- dies will be given. I. The Utilization of Non-Proteig_Nitrogen Sources Dyer (1961) states that with increased grain feed- ing resulting in a decreased roughage consumption, pro- tein could be a limiting nutrient in livestock rations. Urea offers one of the best ways of increasing protein intake under these conditions. Reid (1955) reviewed the current research dealing with urea utilization and its effect as a protein-sparing compound. Two factors in the composition of the ration, available carbohydrate and level of protein, affect the Optimum utilization of urea. Mills gt g1. (1942) studied the presence of available starch on the utilization of urea using a three-week adjustment period, six rations, and a fistulated animal. The rations were as follows: (1) Timothy hay, (2) Timothy hay (10 pounds) plus 4 pounds corn starch, (5) Ration 2 plus 150 grams of urea, (4) Timothy hay (10 pounds) plus 150 grams of urea, (5) 2O Timothy hay (10 pounds) plus 4 pounds starch plus 0.4 pounds casein, (6) Ration 5 plus 150 grams urea. The ration of'Timothy hay, starch, and urea produced a 57 percent increase in protein utilization, but when casein was added to this ration, the utilization of urea was markedly reduced suggesting that casein is preferred over urea as a nitrogen source by the rumen microbial pOpula- tion. Gallup gt g1. (1955a), Gallup gt g1. (1955b), and Reid (1955) make similar reference to the value of starch for optimum utilization of urea. The level of protein in the ration also affects the efficiency of urea breakdown. Wegner gt g1. (1941) used a fistulated heifer fed corn silage, Timothy hay, and a basal grain mix varying only in the levels of urea and linseed oil meal. When the level of protein in the concentrates was increased to 24 percent, the protein con- tent in the rumen increased; however, when the level of protein of the rumen contents became greater than 12 per- cent, the rate of conversion of urea to protein decreased, showing that there is an Optimum protein level for the most efficient use of urea. Johnson gt g1. (1942) and Reid (1955) report similar results. While the two factors previously reported will give Optimum utilization of urea, Reid (1954) states that in a number of experiments in which urea provided from 21 40 to 70 percent of the nitrogen needed by calves, four months or older, the body weight gains were 82 to 88 per- cent of that of calves fed rations with an equivalent amount of nitrogen in the form of high protein feeds. Thus, in most cases urea is somewhat inferior to conven- tional protein supplements as a source of nitrogen for growth. Bartlett and Cotton (1958), using seven to seven- teen month old calves, showed similar results when a urea supplemented diet was compared to a normal protein diet. Frye gt g1. (1954) fed a 12.5 percent crude protein con- centrate in which urea and ammoniated molasses replaced 50 percent of the cottonseed meal to 24 Holstein and nine Jersey heifers averaging 22-50 months in age. Twenty- five pounds of corn and soybean silage and three pounds of chopped grass hay were included in the ration. Prelimi- nary analysis of the results indicated that urea and am- moniated molasses are comparable in feeding value to cottonseed meal. Baker (1944a) used 72 yearling steers to compare soybean oil meal and urea either singly or in combination in a basal ration of corn silage, ground shelled corn, calcium carbonate, steamed bone meal and salt. The highest level of urea that was fed was 0.172 pound per head daily. They felt that the urea nitrogen was apparently utilized since the average daily gains for the different groups were not significantly different. 22 In a second study, Baker (1944b) found that additions of urea increased the gains of 84 steer calves, but the nitrogen of urea was not as well utilized as the nitro- gen from soybean oil meal. In the past ten years, studies have been made dealing with the effects of varying the levels of urea in the ration. Gallup gt g1. (1955a, b) conducted beef cattle fattening trials using pellets in which urea pro- vided 25, 50, and 85 percent of the nitrogen. Results for eight years and 210 calves showed that the 25 and 50 percent pellets produced gains equal to those produced by the common plant proteins. The 85 percent pellets were unsatisfactory. With sheep, the authors found that ewes made very good use of urea nitrogen, but in lamb-fattening rations, the nitrogen of urea was not satisfactory. These results correspond to the results of Hart gt g1. (1958), who compared urea, ammonium bicarbonate, and casein in a basal ration of 5.58 to 6.0 percent protein. Urea at 1.4 pounds per 100 pounds of ration supported growth of calves equal to casein at 11 pounds per 100 pounds of ration. The calves fed urea at 4.5 pounds per 100 pounds of ration did not grow as well. Lassiter gt g1. (1958) fed 25 per- cent protein supplements containing 5, 5, and 7 percent urea with corncobs as the sole roughage. With increasing levels of urea, the rate of gain and feed efficiency 25 decreased significantly. The authors felt that this de- crease may have been due to a decrease in sulfur content with increasing levels of urea. Thomas gt g1. (1951), as cited by Lassiter gt g1. (1958) and Jones and Haag (1946), have established this fact. Harris and Mitchell (1941a) studied maintenance levels when using urea and casein. They found that nitro- gen equilibrium could be maintained on 20 mg. of urea nitrogen and 161 mg. of casein nitrogen per kilogram body weight, and the biological values of urea and casein at nitrogen equilibrium were 62 and 79, respectively. The biological values decreased with increasing level of in- take. These results correspond to those of Harris gt g1. (1945), who found that the biological values of urea and soybean oil meal fed at 12.4 and 15.8 percent protein equivalent were 54 and 60, respectively. In a second study, Harris and Mitchell (1941b) added urea at 8, 11, and 15 percent of protein equivalent to a basal ration of silage and carbohydrate supplement. The biological values of the rations at the 8, 11, and 15 percent level were 74, 60, and 44, respectively, which agree with their first work (Harris and Mitchell, 1941a) for decreasing biological values with increasing intake. Further, they report that the 11 and 15 percent rations produced a greater rate of gain than the 8 percent urea ration. 24 Nitrogen balance studies have been used as a tool to study the value of urea. Harris gt g1. (1945) used two rations, one with a low-protein content and a second sup- plemented with urea or soybean oil meal with a protein equivalent of 12 or 14 percent to study nitrogen balance. They found that the average percent of nitrogen stored for urea and soybean oil meal was 2.0 percent and 51.4 percent, respectively. The poor performance of urea was attributed to the fact that it may have been fed at a level above its maximum for conversion into protein. Fingerling gt g1. (1957), as cited by Benesch (1941), found similar but not as drastic results with gluten and urea. 11. The Value of Urea in Silage Since urea has been considered by many as a protein- sparing agent, an attempt to increase its usage has re- sulted in the additions of urea in silage. Various re- sults have been reported. Davis gt g1. (1944) used a water solution of urea at concentrations of 0, 10, 50, and 50 pounds per ton as an additive in sorghum silage. Crude protein determina- tions showed that some nitrogen had migrated, but any loss was slight. Free ammonia was noticed at the highest concentrations of urea. The pH for the control and 50 pound urea silages were 5.5 and 7.6, respectively. When 25 these silages were fed to cattle, the 0 and 50 pound urea silages were consumed equally well with complete refusal of the silage containing 50 pounds urea per ton until all free ammonia was released. Means (1945) compared urea- treated and untreated sorghum silage by ensiling sorghum with 10 pounds urea per ton. Three lots of beef cows and three lots of yearling heifers were used in a 77-day feeding trial in which three different rations were fed. They were: (1) Standard Ration--50 pounds of untreated sOrghum silage, 1 pound of cottonseed meal and 5 pounds of Johnson grass hay; (2) 55 pounds untreated silage plus 5 pounds of Johnson grass hay; (5) 55 pounds of urea- treated silage plus 5 pounds of hay. In all three rations the heifers received five pounds less than the cows. The average gain or loss for lots one, two, and three for the beef cows was plus 9, minus 99, plus 15 pounds, respec- tively, showing the superiority of the treated silage. With heifers the standard ration produced the best gains but the treated silage was still superior to the untreated silage-hay ration. Cullison (1944), using beef breeding cows, reported similar results. Woodward and Shepherd (1944) ensiled corn silage with the addition of 10 pounds urea per ton silage. This was fed to milking cows with a low protein concentrate and hay. A second group was fed similarly except the urea 26 was mixed with the concentrates. Neither method of feed- ing had a significant effect since both groups maintained milk production exceptionally well. In both methods of feeding, increasing additions of urea impaired palata- bility. Wise gt g1. (1944) using the same ensiling pro- cedure as Woodward and Shepherd (1944) found that silage with urea had a slight caramelized odor and a brownish color. The crude protein for the treated and untreated silages were 10.79 and 7.48 percent, while the pH's for these silages were 4.5 and 5.6, respectively. When the silages were fed to milking cows, the results were similar to those reported by Woodward and Shepherd (1944). Bentley gt g1. (1955) also reported an increase in crude protein with urea additions to green chOpped corn silage at rates of 17, 20, and 25 pounds per ton. When they expressed the increase in crude protein as a percent of the amount of crude protein added as urea, these percent- ages for the 17, 20, and 25 pounds per ton urea levels were 94%, 112%, and 82%, respectively. Bentley gt g1. (1955) found that urea-treated corn silages were quite palatable to both steers and lambs and compared quite favorably to corn silage and soybean oil meal in feeding value. In contrast, Archibald and Parsons (1945) found urea in silage to be unsatisfactory because of the urea conversion to ammonia thereby causing the silage to have an objectionable odor. Hall gt g1. 27 (1954), comparing urea-treated and untreated sweet potato vine silage, reported that the urea silage had good odor and color. III. Calcium Phggphate and Calcium Carbonate Only a limited amount of research has been done with calcium phosphate and calcium carbonate as additives in livestock feed. Colovas gt g1. (1958) used twelve dairy heifers between 18 and 24 months of age to deter- mine the effect of pulverized limestone and dicalcium phosphate on the nutritive value of dairy feeds. In two different trials, the heifers were fed Ladino clover- bromegrass, Timothy, or grass-legume silage with lime- stone and dicalcium phosphate fed at 50 and 100 gram levels with the silage daily. A 16 percent crude protein concentrate mixture was fed the second year. In the first trial, 100 grams of pulverized limestone depressed the digestibility of the protein and energy in the silages. Fifty grams did not show a significant effect. In their second trial, 2 percent limestone decreased the digesti- bility of both the protein and energy. Two percent di- calcium phosphate had no appreciable effect. With 1.0 percent limestone the digestibility of energy was signifi- cantly depressed. When 2.0 percent dicalcium phosphate was added along with 2.0 percent limestone, it minimized the depressing effect of the limestone, thus leading the authors to suggest that calcium depresses the 28 digestibilities of both protein and energy, whereas phosphorus increased the digestibility of the protein. Klosterman gt g1. (1961) ensiled corn silage with 0.5 percent high-calcium ground limestone (56.66% calcium and 0.29%1magnesium) and 0.5 percent urea. High-moisture ground ear corn was ensiled with 1.0 percent high-calcium limestone and 6.0 percent water. In both trials cattle gained significantly faster and required less feed with the treated as Opposed to control silages. In both treated silages there was a vast increase in lactic acid over the control silage; 78 percent for the corn silage (dry basis) and 125 percent increase for the high-moisture ear corn. In a previous paper, they found a 100 percent increase in acid production with 1.0 percent calcium car- bonate, and a 40 percent increase with 1.0 percent dolo- mitic limestone (Klosterman gt g1., 1960a). Sani (1912), as cited by Watson (1959), treated green fodder with 6.75 pounds per ton mono-calcium phosphate. The treated si- lage retained a green color and had a smell of esters with a high retention of digestible protein. IV. Phogphoric Agig Inorganic and organic acids have been used in si- lage fermentation to increase the acidity of the silage just as soon after ensiling as possible. Most of the research deals with the use of hydrochloric, sulfuric, 29 and other acids for this purpose. Less work has been done with phosphoric acid Egg gg. Virtanen (1955), as cited by Watson (1959), reports several experiments in which hydrochloric, phosphoric, and lactic acids were used. Hydrochloric acid was superior to the latter two in depressing the pH to 5.6. In a later experiment, Stone gt g1. (1945) reported that phosphoric acid at 16 pounds per ton produced a satisfactory silage if the ensilage was not too low in fermentable sugars. Two years later, Hayden gt g1. (1945) varied the amounts of phosphoric acid in nine lots of silage. The acid de- pressed the average pH as well as molasses. In general, the lots were graded as "good," but when fed to milking cows the phosphoric acid treated alfalfa silage was not equal to corn silage in feeding value in equal protein rations. Herman gt g1. (1941) ensiled barley with mo- lasses (60 pounds per ton) and phosphoric acid (eight pounds of 75 percent phosphoric acid per ton) and found no significant difference between these two silages for milk production. Archibald and Parsons (1945) found that phosphoric acid treated silage was unpalatable and in- ferior to other silages with other preservatives. In dealing in the area of additives, the results appear to be quite variable depending upon which study is cited and the conditions of the experiment. With urea, 50 it could be concluded that it is slightly inferior or just equal to the common plant protein supplements in feeding value. Calcium carbonate and calcium phosphate pose a different problem. The value of these additives appears to depend on the form and the level in which it is used in the silage. Phosphoric acid, while it de- presses pH, is much like urea in that treated silages are slightly inferior or just equal to untreated silages in feeding value. Silage Fermentation: The Chemistry and Bacteriology of Different Types of Silage Since silage has become a major portion of the average livestock ration, researchers have attempted to study the chemical and bacteriological changes occurring within an ensiled mass. Russell (1908) reported that the general chemical changes known to occur in silage are the conversion of sugars to carbon dioxide and water, the pro- ductiOn of acetic, butyric, and lactic acids, and the pro- duction of non-protein material from protein. Most of the recent studies dealing with the chem- istry of silages are concerned with the production of the volatile and non-volatile acids and the time of most active fermentation. Esten and Mason (1912) concluded that the most important part of corn silage fermentation 51 begins soon after the crop is ensiled, and for the most part, completed within a few days. Similar results were reported by Bender gt g1. (1941) and Hall gt g1. (1954). Acid Production Barnett (1954) states that acetic acid is a normal constituent of good quality silage and its production is initiated earlier than lactic acid. Butyric acid, which results from microbial action on lactic acid, is usually produced some time after the beginning of fermentation. Irvin gt g1. (1956) determined the organic acids in orchard-grass and alfalfa silages during the first 40-60 days of fermentation. They report that the acid content of the fresh material placed in the silos was usually under 1.0 percent on a dry matter basis with acetic acid predominating. In poor quality silages, butyric acid was present after five to eight days, while lactic acid in- creased during the first five days and then decreased. In good quality silages, acetic acid increased rapidly for the first two days and then increased slowly for the next 40-60 days. Lactic acid increased to as much as 8 to 10 percent in the first eight to twelve days. There was no detectable butyric acid present and prOpionic, formic, and succinic acids occurred only in small amounts. Langston gt g1. (1958) showed similar results with orchard- grass and alfalfa silages. They reported lactic acid 52 concentrations of about 9 percent and acetic acid about 2 percent. Succinic acid increased only slightly. Hampton and San Clemente (1959) report similar acid pro- ductions from thirteen grass silages in Michigan. In an earlier report by Sherman and Bechdel (1918), the acid production in dry corn stover with added water was similar to that of ordinary corn silage. Acid forma- tion in the dry corn stover silage and the ordinary corn silage for the first and twelfth weeks was 0.16, 5.15, 0.87, and 2.24 percent of air dry material, respectively. Dobrogosz and Stone (1957) studied alfalfa silage treated with 0, 8, and 12 pounds of metabisulfite per ton. They concluded that the utilization of sugar and produc- tion of acids in the silages were inversely correlated with the amount of bisulfite added to the silage. Klosterman gt g1. (1960b) analyzed the organic acid pro- duction in whole plant corn ensiled in large glass jars with various neutralizing materials. These materials consisted of 0.5 percent low magnesium limestone plus 0.5 percent urea, 0.5 percent urea, and 1.0 percent urea. The acidity of these silages as determined by pH was 4.50, 4.10, and 4.40, respectively, while the acetic acid con- tent for the three silages was 2.15, 1.92, and 1.71 per- cent on a dry matter basis, respectively. Lactic acid content was 12.05, 8.71, and 12.00 percent, respectively. 55 In a later report, Klosterman gt g1. (1961a) treated corn silage with 0.5 percent high calcium ground limestone and 0.5 percent urea. Likewise, they treated ear corn silage with 6.0 percent additional water and 1.0 percent high calcium ground limestone. When these silages were com- pared to control whole plant and ear corn silages, the treatments had little effect on pH, but they did increase the lactic and acetic acid content. Egcterial Populations and Sequences in Silages When silage studies were first undertaken, two schools of thought were advanced as to the cause of the fermentation and the changes that occur in the ensiled mass: (1) the action of plant enzymes and (2) bacterial action. Since that time, bacterial action has gained prominence as the agent initiating the chemical changes occurring in silages. The majority of the recent research deals with the types of organisms present in silage and their sequence changes. Kroulik gt g1. (1955a) reported that there are many variations in the microbial pOpulations on green plants, but that microorganisms tend to increase with the maturity of the plants. The predominating microorganisms on green plants consisted of "pigmented, aerobic, nonspore- forming, rod-shaped bacteria." Coliforms were also present in large numbers and very few of the bacteria from fresh 54 green plants were similar to those found in silage. None of the microorganisms were typical of lactobacilli found in silage. Allen gt g1. (1957) and Gibson gt g1. (1958) both reported that obligate anaerobes, which are of par- ticular significance in silage, are present only in small numbers in fresh grass. Sherman and Bechdel (1918) state that bacterial counts from dry corn stover silage increased during the first week followed by a continued decrease thereafter. Rods and cocci appeared to be in equal numbers during the first two weeks. As fermentation proceeded the rods be- came more predominant until toward the end of fermentation practically all the bacteria were rods. The results of Kempton and San Clemente (1959) and Langston and Bouma (19600) correspond to these results. Hunter (1918), using grass silage, reported similar results over the first two weeks of fermentation and observed that yeast cells increased for the first two to three days followed by a gradual decline in numbers. In a second report, Kroulik gt g1. (1955b) concluded that the numbers of bac- teria increase rapidly in high-moisture ensiled forage and reach a maximum in five days, thereafter decreasing very rapidly. Coliforms after an increase up to two days stor- age also decreased rapidly. In wilted silage, the bac- teria increased at a much slower rate reaching a maximum 55 at nine days and remained at this level over 16 days be- fore a decrease occurred. There is a definite sequence in which the different types of organisms develop in the silage and this sequence is associated with the quality of the ensiled product. Langston gt g1. (1958) grouped 50 silages according to quality and found that rods were much more predominant in good and intermediate quality silages than in poor si- lages. Regardless of the quality, there was an overall increase in rods with a decrease in cocci as fermentation progressed. The authors also noticed a higher initial percentage of cocci in the better quality forages. Langston and Bouma (1960a, b, 0) show quite similar re- sults. They further state that cocci will persist over a longer period of time in poor forages possibly because of low acid conditions. Isolates revealed that cocci occurred early in forage fermentation but were lost when higher acid producing lactobacilli appeared. Pediococci appeared both early and late in the fermentation process. Lactobacilli usually did not become predominant until after the cocci reached high numbers and produced con- siderable amounts of acids. Allen and Harrison (1956) substantiated the belief that lactobacilli play an active role in the advanced stages of fermentation. They reported that the majority 56 of lactobacilli from six different types of grass silage were strains of Streptobacterium plantarum which is the same as Lactobacillus p1antarum. In a later report, Allen gt g1. (1957) ensiled grass silage in 5 by 5 feet pilot silos. L. plantarum was the predominant type of lactobacilli and after seventeen days 1 x 109 per gram were grown from the lower half of the silage. When grass silage was ensiled in large test tubes, lactobacilli were found to be present on fresh grass at about 1 x 106 per gram, but after 24 hours they had increased to approxi- mately 1 x 109 per gram. Stone gt g1. (1945) made simi- lar conclusions from studying 58 different alfalfa silages over a five-year period. In all cases, the majority of organisms after the first few days of fermentation were members of the genus Lactobacillus. The report of Cunning- ham and Smith (1940) is in agreement with the results of Stone gt g1. (1945); while Langston and Bouma (1960c) state that Pediococcus, Lactobacillus brevis and Lacto- bacillus plantarum accounted for 70 percent of the total strains cultured from alfalfa and orchard grass silages. Gibson gt g1. (1958), working with perennial rye grass at controlled temperatures, reported lactobacillus, strepto- coccus, leuconostoc, pediococcus, clostridium, and bacil- lus develOping extensively in most of the silages. Anderson (1956) stated that excess water with packing tends to favor the development of lactobacilli. 57 Yeasts The presence of yeasts indicates the presence of air in the silage. High-moisture corn grain silage ap- pears to be one type of silage in which yeasts may be pre- dominant. Zogg gt g1. (1961), working with shelled corn at 22, 26, and 52 percent moisture, found a predominance of yeasts rather than molds when samples were taken within a foot of the tOp of the silo. In another report, Benjamin and Jordan (1960) reported that the number of aerobic bacteria, yeasts, and molds was higher in an ensiled corn (50 percent moisture) than in a dried en- siled corn (15 percent moisture). Hall gt g1. (1954) presented results showing that yeast counts were much lower when new barrels of silage were Opened each time rather than sampling from a previous sampled barrel. Ex- perimental error expressed as a coefficient of variation was as high as 50 percent for samples taken within a barrel of silage. Heat Production Chemical reactions occurring in silage produce heat in amounts depending upon the ensiled material and the con- ditions of the experiment. Heat greater than 100° F. re- sults in "tobacco" brown silage with excessive dry matter losses, while "cold" fermentations sometimes produce unde- sirable amounts of butyric acid according to Briggs gt g1. 58 (1959). Temperatures as low as 75 degrees F. may be characteristic of this type of fermentation. Benne and Wacasey (1960) expressed similar conclusions when they reported that temperatures of 80° to 100° F. favor the growth of lactic acid bacteria. Temperature in a silo will vary depending upon the level where it is recorded. Hunter (1917) reported aver- age temperature limits in the center of the silo ranging from 50 to 40 degrees C. and noted a difference in heat production at the top and center of the silo depending on the oxygen content. Allen gt_g1. (1957) recorded peak temperatures of 102° and 92° F. for the tOp and bottom of a silo. Sherman and Bechdel (1918), working with ensiled dry corn stover with additional water, recorded a maximum temperature reading of 57.7 degrees F. from the average of four resistance bulbs after 75 days of fermentation. These results are similar to the results of Hall gt g1. (1954) with sweet potato vine silage. Kempton and San Clemente (1959) reported silage temperatures at different depths three weeks after ensiling. In two well-preserved silages the highest temperatures were 151° F. and 111° F. In one silo containing spoiled silage, the highest tempera- ture was 114° F. and in an overheated silage the highest recording was 158° F. Only one study has been conducted in which temperatures were recorded in high-moisture corn. Lassiter gt g1. (1960) stored high-moisture corn in two 59 different years. In 1957, ground shelled corn at 26 per- cent moisture, ground shelled corn at 40 percent moisture, and ground ear corn at 56 percent moisture were ensiled. The 26 percent ground shelled corn produced the highest temperature followed by 40 percent ground shelled and 56 percent ground ear corn. All forms of corn reached peak temperatures of about 78° to 95° F. at approximately eight to ten days. In 1958, 52 percent moisture ground ear corn and 52 percent shelled and ground shelled corn were stored. The 52 percent ground ear corn produced the highest temperature followed in descending order by the 52 percent ground shelled corn and the 52 percent shelled corn. Esten and Mason (1912) stored corn silage at con- trolled temperatures of 40°, 50°, and 70° F. They report that the percent acids in terms of lactic and acetic were 0.57, 1.18, and 1.89 percent per gram of silage, respec- tively, for these temperatures. Silage fermentation has been extensively studied. The production of organic acids is a principle process in fermentation and the types and levels of different acids determine the quality of the silage produced. High levels of lactic and acetic acids are a sign of intermediate to good quality silage while high levels of butyric with decreasing levels of lactic acid are characteristic of poor quality silage. 4O Cocci and rods appear to be the predominant types of bacteria in silages. Cocci appear to decrease in numbers and rods increase as the fermentation proceeds and acid concentration increases. The number of yeasts will vary depending on the type of substrate and the presence of air either entering or trapped in the silage. The optimum silage temperature is generally between 80° and 100° F., but it may vary depending upon the level in the silo at which it is recorded. EXPERIMENTAL PROCEDURE The experiments in this study cover a period of two years' work with high moisture ground ear corn. Trial I In October, 1960, twelve 5 by 7 foot experimental concrete stave silos with a capacity of approximately 2 tons each were constructed. On October 51 and November 1, 1960, ear corn was harvested at approximately 25 percent moisture using a standard corn picker. The corn was ground through a power take off burr-mill set so that all kernels were broken. Additional water was added at the silo to bring the final moisture content to the desired level. In Trial I, urea at 20 pounds per ton, 85 percent phosphoric acid at 0.75 and 1.5 percent, 1.0 percent monobasic calcium phosphate, 0.75 percent calcium car- bonate, and soybean oil meal at 125 pounds per ton were added to the corn in different combinations at the burr- mill. The following regime was used: Silo 1: 28 percent moisture ear corn Silo 2: 28 percent moisture ear corn plus 20 pounds urea per ton Silo 5: 28 percent moisture ear corn plus 20 pounds urea per ton plus 0.75 percent phosphoric acid Silo 4: 28 percent moisture ear corn plus 20 pounds urea per ton plus 1.5 percent of an 85 percent phos- phoric acid solution 41 42 Silo 5: 28 percent moisture ear corn plus 20 pounds urea per ton plus 0.75 percent calcium carbon- ate Silo 6: 55 Percent moisture ear corn Silo 7: 55 Percent moisture ear corn plus 20 pounds urea per ton Silo : 55 percent ear corn plus 20 pounds urea per ton plus 0.75 percent of an 85 percent phosphoric acid solution Silo 9: 55 Percent moisture ear corn plus 20 pounds urea per ton plus 1.5 percent of an 85 percent phosphoric acid solution Silo 10: 55 Percent moisture ear corn plus 20 pounds urea per ton.plus one percent monobasic calcium phosphate Silo ll: 28 percent moisture ear corn plus 20 pounds urea per ton plus one percent monobasic calcium phosphate Silo 12: 28 percent moisture ear corn plus 125 pounds soybean oil meal per ton. When the silos were filled, the silages were leveled and packed. The silos were covered with black, plastic sheets and the side of the cover was tied in place. The silages were allowed to ferment for 60 days. During this period samples were removed on the 0, 5, 10, 20, 50, 45, and 60th day with a Seedburo corn probe. Each sampling day the plastic covers were removed and the samples were taken from the tOp 4 to 5 feet of si- lage near the center of the silo. The samples were stored in polyethylene bags at minus l-5° F. until chemi- cal analyses were completed. The determinations of Kjeldahl-N, Ammonical-N, pH, moisture content, urea, or- ganic acids, and ethanol content were completed in the laboratory. 45 Two feeding experiments were conducted using eight of the twelve original silos. Before feeding, 6 to 12 inches of top spoilage were removed from each silo. Twenty Holstein heifers ranging in weight from 515 to 900 pounds were fed the silages in silos l, 6, 10, and 12 in a 46-day trial. The heifers were assigned to five groups of four heifers each on an equal weight basis following a 7-day pre-trial period in which a dry corn plus soybean oil meal mixture (12.8 percent crude protein), five pounds mixed grass hay, salt, and dicalcium phosphate were fed. The silages were fed according to appetite along with 5.0 pounds of mixed grass hay, 1.0 ounce di- calcium phosphate, and 1.0 ounce trace mineralized salt. Soybean oil meal was also fed in order that all heifers were offered a similar amount of protein. A control group was fed similarly except they were fed dry corn to appetite. Feed consumptions were kept on each heifer with weigh-backs recorded every other day. Weights were re- corded for three consecutive days at fourteen-day inter- vals throughout the trial. Silages number 5, 4, 8, and 9 were fed in a second 50-day growth experiment. Twenty Holstein heifers weigh- ing 400 to 1000 pounds were allotted into five groups on an equal weight basis. The feeding regime was the same as used in the first experiment. The remaining four silages, 2, 5, 7, and 11, had an objectionable ammonia odor and were not used. Trial II Purchased dry ear corn from the previous year's crop was ground through the same burr-mill that was used in Trial I on May 11, 12, and 15, 1961. Eight of the original twelve silos were used in this trial. Duplicate silages were studied at 50 and 45 percent moisture with and without additions of 1.0 percent monocalcium phosphate. Urea and calcium phosphate were added with the corn at the burr-mill. Water was added to the ground ear corn at the silos to obtain the approximate moisture content. The silages were packed and covered with large sheets of black plastic. The following regime was used: Silo l: 50 percent moisture ear corn plus 15 pounds of urea per ton Silo 2: 50 percent moisture ear corn plus 15 pounds of urea per ton Silo 5: 45 percent moisture ear corn plus 15 pounds of urea per ton Silo 4: 45 percent moisture ear corn plus 15 pounds of urea per ton Silo 5: 50 percent moisture ear corn plus 15 pounds of urea per ton plus one percent monocalcium phos- phate Silo 6: 50 percent moisture ear corn plus 15 pounds of urea per ton plus one percent monocalcium phos- phate Silo 7: 45 percent moisture ear corn plus 15 pounds of urea per ton plus one percent monocalcium phos- phate Silo 8: 45 percent moisture ear corn plus 15 pounds of urea per ton plus one percent monocalcium phos- phate 45 The sampling and the analyses were handled the same as in Trial I. Following 60 days Of fermentation, the eight si- lages were used in a 21-day growth trial. Fifty-four heifers weighing 510 to 880 pounds were allotted into nine groups of six heifers each on an equal weight basis following a two-week preliminary period during which dry corn was fed. Top spoilage was removed from each silo. Each of the eight silages was fed to one of the eight groups of heifers with a ninth group fed dry corn as a control. The silages were fed according to appetite with 5.0 pounds of hay, 1.0 ounce dicalcium phosphate, and 1.0 ounce trace mineralized salt. Soybean oil meal (average of 1.4 lb./day) was also fed so that each heifer was on an equal protein basis. Feed offered and rejections were recorded for each heifer. Heifer weights were taken once each week and for three days at the termination of the trial. Trial III Following the first two trials in which water was added to dry corn to obtain the desired moisture content, a third trial was conducted in which corn was harvested from one field at the desired moisture levels. The pre- vious year, hay was raised in this field with no 46 fertilization. "Michigan 500" hybrid corn was planted in the field after fertilization with 400 pounds of 8—52-16 and approximately eight tons of manure per acre. Six 10 by 6.5 foot concrete-stave silos were con- structed. The corn for the first two silos was picked on September 19 and 20, 1961, using a two-row corn picker. On September 19, two loads of corn were picked and covered with tarpaulins until the following morning when the first two silos were filled. The corn was ground with a burr- mill as in Trial I and Trial II. In this trial, the corn was put into a grain wagon and each load was weighed be- fore it was transported by a grain sugar into the silos where it was packed after each load. Four c0pper-constantan thermocouples were used in two silos and three in the remaining four silos. An at- .tempt was made to place these thermocouples so that the temperature could be recorded from the bottom, middle, and upper third of each silo. A Leeds and Northrup potentio- meter was used to indicate the temperatures. After each silo was filled it was covered with black plastic and weighted down with silo staves. Tarpaulins were used to prevent the entrance of additional water. The middle two silos were filled on October 4, and the final two silos on October 26, 1961, so ground ear corn was ensiled at three moistures, 40, 54, and 24 percent. The same sampling 47 schedule and chemical analyses were used as in Trials I and II. Samples were removed from the silos through 1% inch holes bored through the doors and closed with rubber stOppers. Bacteriological studies were also included using the same samples. A 57-day growth trial was conducted 45 to 60 days after ensiling using 55 Holstein heifers weighing 500 to 1,000 pounds. These heifers were assigned to seven equal weight groups of five heifers each after being fed dry corn for seven days. The experimental silages were fed for an additional ten-day preliminary period. Each group received one of the silages and one group was fed dry corn as a control. Three-day body weights were taken at the beginning and the end of the trial and every fourteen days during the trial. The feeding regime for hay, minerals, and soybean oil meal was the same as in the previous growth studies. Feed intakes and refusals were recorded for each heifer and sampled weekly for dry matter deter- minations. Chemical Analyses Moisture, pH1 Ammonical Nitrogen, Crude Protein Moisture was determined by drying in a hot air oven at 100°-105° C. for 24 hours. A Beckman pH meter with an external glass electrode was used to determine hydrogen 48 ion activity. Ammonical-Nitrogen and crude protein equi- valents were analyzed by procedures outlined by the Asso- ciation of Official Agricultural Chemists and adapted for high-moisture corn. Urea Determinations The ion exchange resin method described by Hawk £E.él- (1954) was attempted with some modifications. This method was unsuccessful and the procedure described by Brown (1959) was used with modifications. Two g. of high- moisture corn and ten ml. of distilled water were mixed, in a twenty-five ml. erlenmeyer flask, and held for two hours at room temperature. One ml. of extract from the unknown samples plus the standards and a water blank were pipetted into 10 by 150 mm. test tubes. A urea solution (107 mg. of urea in water in a 100 ml. volumetric flask) was used as a standard. Seven ml. of water were added to each test tube followed by one ml. each of a one percent zinc sulfate solution and a 0.5N sodium hydroxide solution. After the addition of the above solutions, the contents in the tubes were mixed thoroughly and allowed to sit for a period of 15 minutes after which they were centrifuged at 2500G. for 20 minutes. After centrifugation, 2 ml. aliquots of each filtrate were put into test tubes and 2 ml. of p-dimethylaminobenzaldehyde sulfuric acid color reagent were added to each sample followed by thorough mixing. 49 After 10 minutes, the Optical density was read in a Beckman "B" SpectrOphotometer at a wave length of 450 Mu. Volatile Fatty Acids Fifty or one-hundred grams of silage were mixed with an equal volume of 0.6N sulfuric acid and stored at 57°-59° F. for at least three days. The liquid portion of these samples was extracted and centrifuged for ten minutes at 20000. The supernatants were removed and stored under refrigeration. Organic acids were deter- mined by the method of Wiseman and Irvin (1957). Ethyl Alcohol The supernatant used in the volatile fatty acid determinations was also used to analyze for ethanol con- tent. The procedure described by Kent-Jones gt gt. (1954) was followed with modifications. Using 50 ml. erlenmeyer flasks, 5 ml. of potassium dichromate (0.2129 grams po- tassium dichromate per liter of water) was mixed with 5 ml. concentrated sulfuric acid, and allowed to cool to room temperature. Paper clips were attached to the base of rubber stoppers and a strip of filter paper was at- tached to the paper clip. One-tenth ml. of the supernat- ant was absorbed on the filter paper, and this was placed inside the erlenmeyer flask for four hours in a 57° 0. water bath. Following the four-hour period, the potassium dichromate-sulfuric acid solution was titrated to a faint 50 pink against a water blank and a 0.05 percent ethanol standard. The final titrating solution consisted of 55 m1. of a 50 percent sulfuric acid solution to which 15 ml. of a methyl orange solution and 1.0 m1. of a ferrous sulfate solution (1.25 grams ferrous sulfate in 15 ml. water plus 5 m1. concentrated sulfuric acid made up to 25 ml.) was added. The ethanol content on part of the samples was determined using a Cenco gas chromotography unit with a one millivolt recording potentiometer with a ten foot Carbowax-6OO column on a sensitivity setting of three. One hundred microliters of each sample were injected into the unit with a micro-syringe. A time period of 45 minutes was required for each sample with the unit set at 7 pounds helium and at a temperature of 117°-ll8° C. Ethanol at 0.25, 0.5, and 1 percent were used as standards for identification of the unknowns and for plotting standard curves by the peak area method. The methods of Kent-Jones gt g1. (1954) and the gas chromotography unit proved to be in close agree— ment. Bacteriological Procedure In Trial III, bacteriological samples were taken with a Pennsylvania hay borer on the 0, 5, 10, 20, 50, 45, 51 and 60th day of fermentation. The samples were placed in clear plastic bags and were immediately transported to the laboratory for plating and microsc0pic examination. The O-day samples from silos 5, 4, 5, and 6 were placed in a cooler over night and plated the following day. All other samples were plated within 4 hours after sampling. One gram of silage was placed into 125 ml. sterile erlenmeyer flasks along with 99 ml. sterile distilled water. These were shaken manually twelve to fifteen times in a l2-inch arc to dislodge any bacteria attached to the corn. Nine ml. of Azide Dextrose Broth (Baltimore Biological Laboratory No. 11499), which had been auto- claved at 115° C. with 15 pounds pressure for 15 minutes, was distributed into sterile disposable plastic test tubes, 17 by 100mm (Falcon Plastics, No. T171000). One ml. Of the original 102 dilution was pipetted into the first tube and subsequent dilutions were made thereafter. The tubes were stored at 52° C. for 48 hours with an in- spection for growth at 24 hours. Following the 48-hour growth period, a microsc0pical examination was conducted on the growth in the azide tubes. This procedure yielded higher cultural counts than plating on nutrient agar. Lactobacilli were plated from the 102 dilution used for total counts and additional dilutions were made with 52 9.9 ml. sterile distilled water in the sterile plastic test tubes. Lactobacillus-Selective Medium (LBS medium, Baltimore Biological Laboratory, No. 106646) was pre- pared in liter quantities and used as prescribed. Dilu- tions of 10°, 107, 108 , and 109 were prepared and pour plates made from these dilutions. The plates were incu- bated at 52 degrees C. for 48 hours. Inspections for growth were made at 24-hour intervals with final counts at 48 hours. Yeast and mold growth was determined following the same procedure as was used for Lactobacilli. Autoclaved Potato Dextrose Agar (Difco Laboratories, No. 0015-01) was employed as the growth media with approximately 1.6 ml. of a 10 percent tartaric acid solution per 100 ml. of medium to inhibit bacterial growth. Plates were prepared from dilutions of 103, 104, and 105 with incubation at 52 de- grees C. for 48 hours and growth inspections at 24 hours. Occasionally, longer periods of growth were required be- fore total counts could be made. Anaerobic growth was determined with the use of two media, Fluid Thioglycollate Medium (Difco Laboratories, No. 0256-01) and Brewer Anaerobic Agar (Difco Laboratories, No. 0455-02) with 0.5 percent glucose following the same procedures as were followed for Lactobacilli, yeasts, and 6 8 molds. Plates from dilutions of 10 , 107, 10 , and 109 55 were poured and allowed to solidify. Anaerobic conditions were produced by the use of a Brewer's Anaerobic jar. Oxygen in the jar was removed by evacuation of air and replacement with natural gas. Remaining oxygen was re- moved via the action of an electrically heated catalyst. The jars were left at room temperature for 48 to 72 hours before total counts were made. RESULTS Chemical and Bacteriological Studies pH The results are given in Table I. Urea was a con- stant additive in all but three silages in Trials I and 11. Its effect upon silage pH is presented in Graph I. The silages containing 20 pounds of urea per ton had an initial pH of 4.7, but following 60-day fermentation the pH had risen to 7.4. The initial and 60-day values for silages containing 15 pounds of urea were 6.0 and 5.1, respectively, while these values for the silages contain- ing 0 pounds of urea were 6.5 and 5.2, respectively. The effect of other additives on pH was also fol- lowed. Phosphoric acid was added to study its pH depress- ing effect. The initial average pH in Trial I for four silages containing phosphoric acid was 5.2 but after 60- day fermentation, the pH had risen to 6.9. The two si- lages containing 1.5 percent phosphoric acid (silos 4 and 9) did have a lower pH than the silages with 0.75 percent phosphoric acid (silos 5 and 8). When moisture content was considered along with phosphoric acid, the 55 percent moisture silage (silos 8 and 9) had a lower pH throughout than the 28 percent moisture silage (silos 5 and 4). The initial pH was 6.5 and the 60-day pH was 8.5 for silage 5L]. 55 .moddmb amulmwn .msadasm ase1oo saw .me .Om .om .0H .m .o no uses as sauna seams smn.m hme.m mw.m 60.: 00.4 ma.e mm saunas ma.m oo.m mo.s om.s ma.e ma.¢ sad dams HHH asaaa os.s mm.s mo.m ma.e wa.s mm.s om.m mo.m ma assuoo om.m mm.s om.m sm.m om.e Ho.o ma.o mm.o ems uses HH HOHHB mo.m mm.m mo.o Hu.m mm.m me.m 06.4 Hm.m no.6 mm.a mm.w mm.m ma asenoo um.m mm.o am.m am.s oe.o oa.a no.4 mm.a mo.m mm.o mm.u oe.m sea use: H asses ma as 0H m m a m m s m m H sunsez oHam ssqum amoo mam so as .H mamas 56 (mm: “.0 wmw>mn szmmmma 1.53 9.31.6 zmoo m._._o_0< NIP . Amide oz..=mzm mmt< ms...- ow mm Om JV 0? mm Om mm ON n. O. n o 4 — 1 — 4 q 00.? 2mm: Sorta; :3. TM 1. . 1111T1111171 7.1.1.11 \1 1111111111 / \oos \\ [IT], / 1 I I I, // I. d I H I z 71, ,- . Emma .mm: a: wear». m N/\V.oo m \\ .l - co.» \ 2mm: .mm._ 08 most. m . . 1 cos H Idm4 hzmmmuua ._.< mo<1__m 2100 «EM mmahmai 10.: no “In: >._._o_o< MI... Amide 02....mzm thud m2; . ow mm on mw 0v on on 0N ON 0. o. m o ooh Exams: s en- mo.=m NM. 1. \\III]II '. A \1 \\1 ‘ 1/1 1 Jfilooed \\\\\ M 40 I H \\ Exams: s o: mo.__m m ,y . w ooh 12345.2 New“ moat. ~\ cos H 7555 59 111 111 0.0m o m.m e.mm ass on 5.: a.o m.m o H.ma e.m ass on mmm14mmmm mi} mi} Ema 8.1m Tam mama eds Rm has 8 o m.m o o o o.mm m.m m.o has 0m HH Heads 0 m.sH o.m a.ms 6.0 o.¢a o.a o.HH m.m a. a. m.sa see om m.sa s.om m.mm m.mm 5.0m m.am u.ms m.oa m.aa e.ma m.m m.ma ass on H Hesse IIIIIIIIIIIIIIIIIIIIIIIIIIIIII II M\§§ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 1mH as 0H m m a m m 4 1m. m H assess oaam mQHod UHZOHmOmm 92¢ OHmHBDm uHH mamde 60 TABLE III: EFFECTS OF MOISTURE ON OROANIC ACID PRODUCTION _ ‘ (uM/s) (qus) Trial I a) 26-28% 47 19 (7)b 55 18 (7) b) 30-35% 60 2o (5) 44 13 (5) (P <0.10) (P 10.12) Trial II a) 25-30% 46 15 (4) 40 15 (4) b) 40—45% 128 28 (4) 198 32 (4) (P < 0.01) (P < 0.01) Trial III a) 24% 9 0.6 (2) 15 8 (2) b) 34% 361 24 (2) 124 17 (2) c) 40% 54d 7 (2) 164 3 (2) (P <0.01) ’ (P < 0.01) aStandard Deviation. :Number of Silos. dLactic acid determined colorimeterically. 54 and 40 percent significantly higher than 24 percent moisture corn. percent moisture). In Trial II, it was observed that 1.0 percent monobasic calcium phosphate reduced the concentra- tion of butyric and propionic acid at the 45 percent mois- ture level but not at the 30 percent moisture level. 61 Lactic acid was increased and acetic acid decreased with additives of monobasic calcium phosphate. In Table III, it can be seen that increased moisture increased the ace- tic and lactic acid content. In Trial III the lactic acid production in silages at 40 percent moisture was higher (P < 0.01) than at the 54 percent moisture level. Urea There was a gradual decrease in the amount of urea present in the silages as shown in Table IV and Graph III. TABLE IV: EFFECT OF TIME ON UREA CONTENT (Mean Values for all Silos with Urea) TRIAL I TRIAL II SamPling Days (20#‘urea/ton)a (15# urea/tonyE mg/g m878 o 4.4 2.9 5 4.1 1.9 10 2.7 1.6 20 1.9 1.4 50 1.5 1.3 45 0.9 1.0 60 ~-- 0.65 aValues determined on wet basis. 62 .ooEmn. 20:35.25... >< la 1.51... 00.. Jill Eon. no moqmm><1n 1.55 - //II1IIII .\ If .I. / - / cod / 1 /1 [5% do .mmn om 92.2528 Moo... HH I¢¢ nonafiz deHmB GZHQmmm zmoo MMDBWHOEImUHm mo mBQDmmm "HHH> mgmde 71 no significant differences in weight gains between dif- ferent moisture contents, 1.0 percent monobasic calcium phosphate increased weight gains by 19 percent (P < 0.12) as shown in Table IX. In Trial I, Experiment I, silages with and without urea were fed. The average daily gains for these silages were 1.55 and 1.66, respectively. TABLE IX: EFFECT OF MONOBASIC CALCIUM PHOSPHATE ON WEIGHT GAINS Trial II Number Daily Gains (lbs/day) No CaH4 (P04)2-H20 24 2.06 1% CaH4 (P04)2~H20 24 2.44 Feed Efficiengy. In Trial I, there were no sig- nificant differences among silages. The feed efficiency of the 28 percent moisture silage of Experiment II ap- pears as if it would be significantly higher, but the difference was primarily due to one animal. In Trials II and III, animals fed the wetter silages (54-45 per- cent moisture) required less (P < 0.05, P 1<0.25) dry matter per pound of gain. 72 Feed Intake. Feed intake presented the same pic- ture as feed efficiency. In Trials II and III, the heifers on the wetter silages ate less (P < 0.01) dry matter per day than heifers on the drier silage or the control ear corn. Further, there was a significant inter- action (I’c0.01) between moisture and monocalcium phosphate in Trial III. There were no differences in feed consump- tion observed in the first two feeding studies of Trial I. Correlations Between Animal Performance and Silage Quality Measurements When the growth and chemical studies had been ter- minated, an attempt was made to correlate the data. The results are presented in Table X using 100—110 animals and 22 silages. There was a positive correlation with 60-day lactic acid and a negative correlation with 50—day acetic acid showing a difference for the two major acids found in silage. Acreage Yields-~Fermentation Loss The third phase of this study pertains to factors in the storing and feeding of high-moisture corn that are not related to direct chemical reactions. Corn yields per acre were obtained in Trial III. The exact field area and yield were difficult to obtain because of an uneven field and limitations of the corn picker. The re- sults are presented in Table XI. 75 TABLE X: CORRELATION COEFFICIENTS BETJEEN AVERAGE DAILY GAIN AND CHEMICAL COMPOSITION Average Daily Gain vs. Coefficients Coefficients Silage Quality Measurements H.M.C. Gordon et al. (19671“ 1) lO-day pH - 0.09 --_- 2) 60-day pH - 0.15 - 0.56 5) 50-day Lactic Acida + 0.05 + 0.56 4) 60-day Lactic Acida + 0.21 5) 50-day Acetic Acida - 0.26 - 0.72 6) 60-day Acetic Acida + 0.07 7) Ammonical -Nb + 0.18 - 0.890 8) Lactobacilli (50-day) - 0.27 ---_ 8Dry matter basis. bWet basis. cAs percent of total nitrOgen. dGordon gt g;., J. D. S., 44:1299:l961. TABLE XI: THE EFFECT OF MOISTURE ON YIELD PER ACRE Moisture percent Dry Matter Yield (lb/acre) 24% 5,002 54% 4,724 40% 4,204 74 The fermentation loss from the silages in Trial III are presented in Table XII and reveal about a 5 per- cent 1oss in the silo when high-moisture ear corn is en~ siled. It is interesting to note that as the moisture level decreased, the spoilage in the silage increased. Again, this may be a result of less compaction in the drier silages with the incorporation of air which pro- vides a perfect media for the initiation of the spoiling processes. TABLE XII: LOSSES IN HIGH-MOISTURE GROUND EAR CORN Moisture 40%3 54%a 24%a Dry Matter Ensiled (lbs.) 12,192 15,226 15,006 Dry Matter Fed (lbs.) 11,995 11,584 15,574 Top Spoilage (dry matter) 552 915 1,146 Percent Recovery 105 94 97 aMean value from 2 silos. DISCUSSION Since the objective was to study the physical and chemical effects of moisture level and different additive compounds on the feeding value and fermentation of ear corn silage, it was a necessity to study as many silages as possible and with as many additive combinations as possible. With the analyses of 26 silages, our objectives in part were obtained. When urea was incorporated into the silage at 20 pounds per ton, there was a continual rise in pH. This increase could possibly be due to the neutralizing effect of ammonia from the breakdown of urea. At 15 pounds per ton, this effect on pH was not as drastic, especially when compared with the control silages. Klosterman gt g1. (1961a, b), ensiling the entire corn p1ant,found similar results of increasing pH with increasing levels of urea. In all cases, their pH values were lower than the values found with the ear corn silage in this work. Since Klosterman g; g1. (1961a, b) had found favorable results with limestone (CaCOB), this compound was further inves- tigated. The results were not favorable in this work which may have been due to the added urea. Further, Klosterman gt g1. (1961a, b) used a special grade of lime- stone which may have resulted in a different chemical picture. 75 76 The results with phosphoric acid did not improve animal performance or decrease ammonia odor possibly be- cause of the level of urea combined with it in the si- lage. However, an indication of better results was ob- served with phosphoric acid at a concentration of 1.5 percent with the silage at 55 percent moisture. Further, research should be pursued on this mixture. One percent monobasic calcium phosphate produced favorable results at the lower level of urea (15 1b/ton). Monobasic calcium phosphate exhibits an acid reaction thereby depressing the initial pH. Higher moistures, which provide a suit- able media for both chemical and bacteriological reac- tions, further depressed the pH. Klosterman gt g1. (1961a) reported an increase in organic acids (acetic and lactic) with increased moisture and limestone. The results of the chemical analyses of organic acids in this study substantiate these findings, especially with the higher moisture levels. These data also showed an increased production of butyric and pro- pionic acid with higher moisture although these results have not been reported elsewhere. One percent monobasic calcium phosphate increased the lactic acid content and decreased the acetic acid content. One possible theory on the mode of action of monobasic calcium phosphate is that it depresses the initial pH to a level where the first 77 fermentation acid (acetic) is not produced. At lower pH's lactic acid production is stimulated, since lactic acid bacteria become the predominant organisms in this fermentation environment. Since more lactic acid is pro- duced, a better silage results under these conditions. Further research is needed on this subject. Acetic acid accounted for 1/5 to 2/5 of the total acid production in the silages of Trials I and II. Langston 23 gl. (1962) working with aerated and sealed Orchardgrass and Alfalfa silages showed an increase in acetic acid content in aerated silages as compared to the content in sealed silages. Since in Trials I and II sam- ples were removed from the tOp, the seal was removed each sampling time suggesting that these silages may have re- sponded like aerated silages. In Trial III, where less acetic acid was produced, samples were removed through silo doors so that the seal remained intact resulting in less aeration and higher lactic acid production. No reports on the breakdown of urea have been pre- sented, but this study reveals a steady degradation of the compound throughout the fermentation period. A large percentage (75-9 %) of the released ammonia was accounted for in the silage. The increase in crude protein can be accounted for from the added urea. These results cor- respond to those of Wise §§_gl. (1944), Bentley gt g1. 78 (1955) and Gorb and Lebedinskij (1960) in that they re- port an increase in crude protein content with additions of urea. Sherman and Bechdel (1918), Langston 23 gl. (1958), and Langston and Bouma (1960a, b, c) reported a predomi- nance of cocci in the early stages of the fermentation process followed by an increase in the higher and more active acid-producing rods with a subsequent decrease in cocci. A similar pattern of bacterial development was observed in the higher moisture silages. As the moisture level decreased more cocci were present throughout the fermentation. These results were not consistent in all observations. Since the lactic acid production in the 24 percent moisture silages was significantly lower than in the 54 and 40 percent moisture silages, this proposes two impressions about the bacterial counts in the 24 per- cent moisture silages: (1) the lower moisture level of the 24 percent moisture silages may have provided a growth media for the lower acid-producing cocci, and the higher acid-producing lactobacilli may not have been pre- sent in large enough numbers over a long period of time to grow and produce appreciable amounts of lactic acid; and (2) it is possible that at the lower moisture levels the species of lactobacilli present may have been dif- ferent than those in the higher moisture silages. 79 Since ear corn silage exhibits a strong yeast smell, an attempt was made to plate these yeasts. Large numbers were present in all silages, but an increase was noticed in the drier silages. Zogg gt gt. (1961), work- ing with shelled corn at different moisture levels, found a predominance of yeasts rather than molds when samples were taken within a foot of the top of the silo. The results of this study showed that yeasts were present throughout the silage since the samples were taken below one foot of the t0p. Entrapped air due to less compac- tion possibly enhanced yeast growth. Mold and anaerobe counts support this theory. Silage temperatures in high-moisture corn have been reported by Lassiter gt gt. (1960) using various forms of soft corn at different moisture levels. The peak temperatures in their silages were attained in eight to ten days which corresponded to peak temperatures of six to twelve days in the present study. The peak tem- perature observed in the silages varied depending upon the moisture level. Some concern was raised over whether the silage was cooling off or actually heating, but out- side temperature plus chemical data does not warrant con- cluding that the silages were cooling off during the fer- mentation period. 80 Animal performance has been reported by numerous researchers. Beeson gt gt. (1956), Beeson gt gt. (1957), Culbertson gt gt. (1957), Beeson gt gt. (1958), Beeson (1958), and Klosterman gt gt. (1961a) report that cattle require 4 to 15 percent less dry feed per unit of gain with ensiled high-moisture corn. Further, there was no significant difference for rate of gain between high and low-moisture corn. The data of this study warrant the same conclusions as to animal gains, but feed efficiency data were variable. These differences were possibly due to the various silage additives. Dry matter yield per acre is an important consid- eration in the use of high—moisture corn. Ross and Rea (1959) report that higher dry matter yields per acre were obtained when corn was picked wet as compared to picking as number two corn. The data of this study are in direct disagreement with the results of Ross and Rea (1959). Difficulty in measuring the field area plus extreme wastage by the corn picker may have affected the results. Further research should be conducted on this problem. The loss in dry matter during fermentation is an- other phase of silage making where the farmer is confronted with a problem. This loss can amount to 0-50 percent or higher depending upon crop quality, the physical features 81 of the silo and the care, knowledge, and precision in en- siling the crop.‘ At the present time only a small amount of research has included results of the dry matter losses occurring in the silo when high-moisture corn is ensiled. Klosterman gt gt. (1960b) report that the total dry mat- ter losses between the amounts stored and amounts fed for limestone-water treated silage (46 percent moisture), untreated silage (40 percent moisture), and dry ear corn were 16.8, 16.5, and 12.6 percent of the amount stored, respectively. In this study losses in the silo including top spoilage were not over 6.0 percent. Further, Lassiter gt gt. (1960) reported that corn containing 25 to 55 per- cent moisture produced the least spoilage. The results in this study show just the reverse situation with these two moisture levels producing more spoilage than 40% moisture silage. This problem is not settled as can be seen from the conflicting results. When the results of the chemical phase and the feeding phase were correlated, there was a direct rela- tionship between the results in this study and the re- sults of Gordon gt gt. (1961). This was true with the exception of ammonical-N, but there was a difference in the basis of calculation. 0n the basis of the correlation coefficients, it would appear that at the present there is still no direct chemical measurement with the exception 82 of lactic acid and acetic acid to measure the nutritive value of silages. Ammonical-N and pH, the pOpular cri- teria for measuring silage quality, were of no value for predicting animal performance in this study. SUMMARY In a two-year study, high-moisture ground ear corn was ensiled at different moisture levels and with the ad- dition of different chemical compounds. The chemical products from the resulting fermentation were studied using 26 different silages. Bacteriological and tempera- ture studies were also conducted using six silages. Twenty-two of the twenty—six silages were utilized in growth studies using Holstein heifers to study the nutri- tive value of the fermented corn. Following the comple- tion of the chemical, bacteriological, and growth studies, correlation coefficients were run in an attempt to corre- late the chemical quality of the individual silages with animal performance. The effect of urea upon the pH was noted as si- lages with 20 pounds of urea per ton increased in pH throughout the fermentation period. With 15 pounds of urea per ton, this effect was not noted. The silages con- taining 20, 15, and 0 lb. of added urea had an initial pH of 4.7, 6.0, and 6.5; but following 60 days fermentation the pH had changed to 7.4, 5.1, and 5.2. In a second trial there was a depression (P < 0.01) of pH with high moisture and with the addition of 1.0 percent monobasic calcium phosphate. The effect of moisture content was 85 studied in a third trial as 40 and 54 percent moisture silages depressed the pH (P < 0.01) whereas the Opposite effect was noted with the 24 percent moisture silages. There was no direct pattern for butyric and pro- pionic acid production in individual silos, but there was a tendency for more butyric and propionic acid production in the higher moisture silages (54-45% moisture). One percent monobasic calcium phosphate reduced the concentra- tion of these two acids at higher moisture levels. In all three trials acetic and lactic acid were significantly higher at the higher moisture levels. Lactic acid was increased and acetic acid decreased with the addition of 1.0 percent monobasic calcium phosphate. In general, 50 percent of the urea was broken down within 20 days and 80 percent within 60 days. Monobasic calcium phosphate significantly depressed (P < 0.01) the rate of breakdown of urea in one of two trials. There was a significant increase (P < 0.01) in crude protein with additions of 20 pounds of urea. In two trials there were slight increases (P < 0.25), (P < 0.25) in crude protein with the higher moisture silages. This effect was not noted in a third trial. The ethyl alcohol content of the silages was in- creased in the higher moisture silages. The average content was 0.2 percent. 85 The total microbial counts were within the same log range for 40, 54, and 24 percent moisture silages. Lactobacilli counts decreased in the 24 percent moisture silages. The mean log counts of Lactobacilli from the 45- and 60-day samples for 40, 54, and 24 percent moisture silage were 8.5, 8.6, and 7.9. Yeast counts increased and anaerobe counts decreased with decreasing moisture. With the exception of one growth study, there were no significant differences in weight gains when ensiled ground ear corn (24-45% moisture) was compared to ground dry corn. One percent monobasic calcium phosphate in- creased gains by nineteen percent. In two growth studies, animals fed the wetter silages (54-4 % moisture) required less (P < 0.05, P < 0.25) dry matter per pound of gain than heifers fed the drier silages. This same pattern developed with feed intake as the heifers fed the wetter silages consumed less (P < 0.01) dry matter per day than the heifers on the drier silages. Correlation coefficients using average daily gain and silage quality measurements showed a negative corre- lation.with 50-day acetic acid and a positive correlation with 60-day lactic acid and average daily gain. There was a negative correlation with both 10- and 60-day pH and average daily gain. Fermentation loss in the silage averaged three to six percent regardless of the moisture level. LITERATURE CITED Allen, L. A., and J. Harrison. A comparative study of 1956 lactobacilli from grass silage and other sources. Ann. of Appl. Biology 25:546-557. Allen, L. A., Harrison, J., Watson, S. J. and A. S. 1957 Ferguson. A study of the chemical and bacteri- ological changes occurring in grass silage. J. Agri 0 $01 0 27 : 271-295 0 Anderson, K. J. Microbiology of silage. Nature 177:96—97. 1956 A.O.A.C. 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Dairy Sci. 44:485-490. ---------- Definition of silage terms. Rept. of committee 1959 on silage nomenclature appointed at the time of the second silage conf. Beltsville, Maryland. pp. 1-69. it‘JVfiPE 9:; £615- RIES "‘11111111MM‘1MA‘