;r c .;. i ;-~;; r TPjpq: i-,'usl .la rr -i ~d ~"~~"-"; a, -:41 r- Z BULLETIN 393 OCTOBER 1969 Effect of Winter Feeding Level on Brood Cow Performance AGRICULTURAL EXPERIMENT STATION AUBURN UNIVERSITY E. V. SMITH, DIRECTOR AUBURN, ALABAMA SUMMARY OF FINDINGS Mature beef brood cows can be wintered on hay alone provided they are in good flesh at beginning of winter and receive ample feed immediately following so that body weight losses can be recovered. Young cows were found to require special treatment, however, probably including feeding of additional protein and energy. Specific findings are summarized here: (1) Cows confined to a bermudagrass sod lot and full-fed medium quality grass hays lost an average of 110 pounds during winter (November 1-April 1). This weight loss was not excessive and did not adversely affect mature cow performance. (2) Calves from cows fed 2 pounds of cottonseed meal daily and a limited amount of grass hay (17.6 pounds) on browse pasture during winter were 47 pounds heavier at weaning than those from restricted-fed cows - 484 vs. 437 pounds. (3) Calves from the optimum-fed dams graded slightly higher at weaning, but stocker grades were not different. Optimum-fed calves were valued at $13.37 more per calf at weaning, primarily because of the 47-pound weight advantage. (4) Replacement heifers reared under the restricted-feeding regimen were considerably smaller at 2 and 3 years of age, but about equalled the better-fed heifers by 6 years. (5) Optimum-fed steer calves were 44 pounds heavier at weaning than those from restricted-fed dams, and this weight advantage was maintained through a post-weaning, growing-finishing program. (6) Sixty-seven per cent of replacement females on the optimum regimen calved initially at 2 years of age, as compared with 50 per cent of those from the restricted feeding. In addition, more of the optimum-fed heifers that calved at 2 years of age also calved again the following year. (7) The overall calving rates for cows 3 years and older were 87 and 86 per cent for optimum and restricted, respectively. Percentage calf crop weaned was 81 and 78 per cent. (8) Feeding treatment did not affect calving date. (9) Milk production of cows on both feeding treatments declined substantially during winter. However, restricted-fed cows responded to lush spring pasture and, after 60 days on pasture, had milk production equal to cows that were better fed during winter. *-.r e a.. "i . t\ z4 3 .Q -- * -- .4.. Beef cows and calves on the two levels of winter feeding at the Lower Coastal Plain Substation are shown during one test year. The optimumfed group (top) was fed good quality grass hay along with daily feeding of 2 pounds of cottonseed meal. In addition, the animals had access to an improved river bottom pasture that provided browse in early winter and considerable early spring grazing. Cows on restricted feeding (right) were full-fed medium quality grass hay as their only feed, while confined to a small gross sod lot. * a Lg: , CONTENTS Page SUMMARY OF FINDINGS-- 2 EXPERIMENTAL METHODS---------7 RESULTS AND DISCUSSION--- --- -- --- - - --- - 8 Hay Quality and Consumption-8 Winter Weight Loss of CowsCalf Weaning Weights ----------10 9 Growth Rate and Mature Size of Replacement Heifers 10 Post-W eaning Steer Performance----------------------13 Reproductive Rate of 2-Year-Old Heifers -------------Reproduction 13 of All Cows---------------------------14 Blood Com position---------------------------------15 Milk Production --------------------------- ------ 16 Evaluation of W eaned Calves ------------------------ 17 ---------------- LITERATURE CITED-------------------- 19 FIRST PRINTING 4M, OCTOBER 1969 Effect of Winter Feeding Level on Brood Cow Performance V. R. R. HARRIS, Associate Professor of Animal Science L. BROWN, Superintendent, Lower Coastal Plain Substation W. B. ANTHONY, Professor of Animal Science WHEN THE STUDY reported here was begun in 1957 there were approximately one million beef brood cows in Alabama. At that time there was little reliable research information available concerning different feeding regimens for wintering such cattle. Records from the several brood cow herds of Auburn University Agricultural Experiment Station System showed that grazing was available only 8 to 9 months of the year (March-November) and that supplemental feed was needed for the remaining 3 or 4 months. However, little was known about effect of nutrition level during the winter feeding period on the subsequent performance of cows on spring-summer grazing and on the pre- and post-weaning performance of their calves. Foster and his co-workers (2) at the North Carolina Agricultural Experiment Station fed varying levels of protein supplement to spring-calving cows wintered on forest range. Loss of weight was less and summer gains of the calves slightly greater in the group receiving the highest level of protein supplement. Most of the differences in winter weight changes of cows were offset during the summer. Zimmerman et al. (7) at the Oklahoma Agricultural Experiment Station studied the effect of three winter levels of nutrition on the growth and reproductive performance of beef brood cows in a spring calving system. On the lowest level, the test animals made no gain during the winter as calves and lost 200 pounds each winter feeding period thereafter. They had no difficulty at first calving and there was no effect on percentage calf crop weaned. In 2 out of 3 years on this low nutritive level, birth weights of calves were reduced, and in all years the calving interval was slightly increased. On the two higher nutritive levels the weaning weight 6 ALABAMA AGRICULTURAL EXPERIMENT STATION of calves was increased, but this additional weight did not offset the increased cost of winter supplement. The low nutritive level had a slight depressing effect on structural growth of the cows. In a later Oklahoma report (5), Pinney et al. indicated that calf birth weights, milk yield of dams, calf weaning weights, and percentage calf crop weaned were depressed by the low nutritive level. However, differences became smaller as the cows approached maturity. The medium and high feeding rates on which the cows gained 0.5 to 1.0 pound daily during winter (November 1-April 15) resulted in the earliest conception, highest milk production, and heaviest calf weights at birth and weaning. However, the continuous high feeding rate also was detrimental in that milk production was decreased and percentage of live calves at first parturition was lowered. Pinney et al. (4) reported on the effect of pre-weaning level of nutrition on subsequent feedlot performance and carcass composition of calves from the study already mentioned. Pre-weaning retardation resulted in a 30 per cent reduction in weaning weight, 11 per cent reduction in final feedlot weight, and a decrease of 11 and 14 per cent in total lean and fat, respectively; however, feed efficiency was improved and there was no adverse effect on gain during the feedlot period. In the Alabama study reported by Smith and Grimes (6), fallcalving cows were either fed protein and energy at recommended levels or at about 70 per cent of that rate. Calf weaning weight and sale price favored the better-fed dams by 42 pounds and 700 per hundredweight. However, economic returns were similar for the two groups. Results from a Virginia study (3) indicate that calves need feed in addition to milk to make satisfactory gains. Creep-fed calves from cows restricted to 50 or 75 per cent dry matter intake of full-fed contemporaries gained approximately 2 pounds daily, whereas those getting only the dam's milk gained 0.33 pound daily. Because of the cost of feeding large amounts of supplemental feed to brood cows, it is important to know the minimum nutritive level conducive to efficient production. This is especially true for cows nursing fall-dropped calves, because of the additional nutrient requirements of a lactating cow and the length of winter feeding period. EFFECT OF WINTER FEEDING LEVEL 7 EXPERIMENTAL METHODS Seven bred Hereford heifers and 10 open Hereford heifers were assigned to each of two test groups on November 1, 1957, at the Lower Coastal Plain Substation, Camden, Alabama. One group was placed on a winter feeding program designed to be optimum for cows wintered in this area. The second group was subjected to a restricted, or low level, feeding plan. The optimum group was full-fed good quality grass hay and hand-fed 2 pounds of cottonseed meal (41 per cent) per head daily during the winter period (November 1-March 31). In addition, the animals had access to an improved river bottom pasture that furnished some browse during early winter and considerable grazing in early spring. The restricted-fed cows were full-fed a medium quality grass hay during the winter (November 1-March 31) while confined to a 3.5-acre sod lot. This lot provided an average of 8,000 square feet per cow, with a range of 3,200 to 21,800. The cows did not receive protein supplement. All cattle were placed together April 1 each year and grazed river bottom, clover-grass pastures until the following November 1. Performance-tested Angus bulls were placed with cows from January 1 to May 1 each year. Bulls were rotated between cow groups on an annual basis. Steer calves of both groups were combined at weaning in a post-weaning, growing-finishing program. This consisted of 4 to 5 pounds of supplemental feed on late summer pasture, followed by cool-season annual grazing and a subsequent drylot fattening period. Steers were slaughtered and carcass data obtained. After weaning, all heifers were managed as one group until November 1. At that time the optimum-level heifers were placed on an improved clover-grass pasture and fed a limited amount of grain until 15 months old. Heifers of the low level group were moved to a small lot November 1 and fed medium quality grass hay. For breeding, both groups were placed with their respective cow herds as they reached 15 months of age. Replacement females were not culled, but three cows were removed from test because of sickness. Beginning in November 1965, all original cows and those that had reached 6 years of age were removed from the study. These animals were retained until all pertinent reproductive data were obtained. 8 ALABAMA AGRICULTURAL EXPERIMENT STATION Milk production data were obtained several times during the study by the oxytocin procedure developed at Auburn University Agricultural Experiment Station (1). On the basis of butterfat content, the quantity of 4 per cent fat-corrected milk (FCM) was calculated and adjusted to a 12-hour value. All cows and calves were weighed November 1 and April 1 each year. Steers on post-weaning programs were weighed at approximately 28-day intervals. Replacement heifers were weighed November 1 and again at 15 months of age. Thereafter, the replacement heifers were treated as cows. Calves were weaned at 250 days (±3 days) and no adjustment was made in weaning weight data for age of calf. Weights were adjusted for age of dam differences: + 15, +10, and +5 per cent, respectively, for cow ages 2, 3, and 4 years. All weaning weight data also were adjusted to a steer equivalent basis by adding 25 pounds to actual weights of heifers. RESULTS AND DISCUSSION Hay Quality and Consumption Hay was full-fed as the sole source of energy during winter to the restricted cows. They received an average of 24.71 pounds daily during the 9-year study, Table 1. Cows in the optimum group that received 2 pounds of cottonseed meal (CSM) daily and had access to pasture got only 17.61 pounds of hay. Thus, the 282 pounds of CSM and pasture browse replaced 1,001 pounds of hay during the 141-day winter period. Feed cost per animal was TABLE 1. AMOUNT OF HAY FED, CRUDE PROTEIN CONTENT, AND PROTEIN INTAKE ON OPTIMUM AND RESTRICTED FEEDING Year Hay fed daily Optimum Restricted Lb. Lb. 13.19 20.24 27.79 12.88 18.37 18.87 15.67 15.33 16.17 17.61 Crude protein in hay Optimum Restricted Pct. Pct. 7.02 10.96 8.47 9.45 7.68 7.20 7.78 8.36 Daily protein intake Optimum Restricted Lb. Lb. 2.16 2.15 2.29 2.50 1.96 1.86 2.01 2.13 1957-58'_ 1958-59._ 1959-60.. 1960-61.. 1961-62.1962-63.. 1963-64._ 1964-65.. 1965-66.. AVERAGE 13.18 23.44 33.25 23.27 25.58 26.90 27.06 23.75 25.96 24.71 6.65 8.52 7.71 9.26 8.36 6.48 6.87 7.69 1.47 1.87 1.86 2.35 1.93 1.46 1.69 1.80 1 Includes crude protein obtained from protein supplement where applicable. 2Both groups wintered on pasture with some browse available. EFFECT OF WINTER FEEDING LEVEL 9 $11.98 for cottonseed meal (@ $85 per ton) and $12.51 for hay (@ $25 per ton). Assuming no charge for pasture, costs of the two rations are comparable. However, calves from the optimumfed cows were 47 pounds heavier at weaning, Table 3. Crude protein contents of the two hays were not different, averaging 8.36 per cent for that fed the optimum group and 7.69 per cent for that fed to the restricted cows (dry matter basis). An intake of 1.6 to 1.9 pounds of crude protein daily is adequate for a mature cow suckling a calf, and cows in the optimum and restricted groups averaged consuming 2.13 and 1.80 pounds per day, respectively, Table 1. For at least 2 of the 9 years, however, the restricted cows consumed insufficient protein (1958-59 and 1964-65). Although this protein deficiency probably was not sufficiently restricted to affect mature cows, it was highly undesirable for heifer replacements entering the group at 15 months of age and for 2-year-old heifers nursing calves. Winter Weight Loss of Cows Body weight changes were recorded for all cows; however, only those with calves on November 1 each year were considered in calculating loss of body weight during the winter period, Table 2. The weight losses of 61 and 110 pounds for optimum and restricted, respectively, were not excessive. All cows were in good condition prior to November 1, because they all had access to good clover-grass pastures beginning April 1. Within a feeding treatment, young cows lost relatively more weight than mature cows, and weight losses became progressively TABLE 2. MEAN WEIGHT LOSSES OF Cows DURING WINTER 1 OPTIMUM AND RESTRICTED FEEDING PERIOD ON Year Level of winter feeding Optimum Restricted Lb. 1957-58 ------------1958-59 1959-60 1960-61 1961-62 1962-63 1968-64 1964-65 1965-66 -43 AVERAGE .... ---------67 144 88 24 69 19 49 55 61 Lb. 216 119 125 70 161 76 61 93 61 110 SOnly cows with calves as of November 1 considered. 10 ALABAMA AGRICULTURAL EXPERIMENT STATION less as cows approached maturity. Weight losses were rather severe (144 pounds) for the 2-year-old restricted females that weighed about 700 pounds on November 1. One-half of these restricted-fed heifers did not calve at 2 years of age, Table 9, thus allowing some compensatory weight gain. Calf Weaning Weights During the 8-year study, calves from the optimum-fed cows averaged 484 pounds at weaning, which was 47 pounds heavier than those from the restricted-fed cows, Table 3. This difference was highly significant (P<.01). The largest difference observed during the 8-year period was 68 pounds and the smallest was 24 pounds. TABLE 3. CALF WEANING WEIGHT DATA ON OPTIMUM AND RESTRICTED FEEDING Year' Optimum Restricted Number Adjusted Number Adjusted of calves weaning wt. of calves weaning wt. No. 12 13 10 19 21 25 20 17 137 Difference favoring optimum Lb. 38 64 46 30 68 24 51 54 47 No. Lb. 1958-59 14 487 1959-60-................... 14 464 1960-61 17 476 1961-62 27 475 1962-63 30 504 1963-64 33 485 1964-65 26 476 1965-66 23 504 TOTAL OR Av._______ STest Lb. 449 400 430 445 436 461 425 450 437 184 484 actually was begun in 1957; however, feeding treatments were changed after first year so data for the 1957-58 calf crop were not included. The difference in total number of calves weaned (47 more for optimum group) is partially the result of more females being born in that group (45 vs. 35 in restricted group) during the years in which replacements were being kept. Based on the number of cows available to calve, the calf crops averaged 85 per cent in the optimum group and 82 per cent in the restricted group. Growth Rate and Mature Size of Replacement Heifers Body weight data for replacement females at weaning (250 days), breeding (15 months), and first calving (2 years) are presented in Table 4. The optimum heifers averaged 41 pounds heavier at weaning, 106 pounds heavier at 15 months, and 50 EFFECT OF WINTER FEEDING LEVEL 11 EFFECT OF WINTER TABLE 4. FEEING LEVEL 1 BODY WEIGHT OF REPLACEMENT FEMALES ON OPTIMUM AND RESTRICTED FEEDING' Year of birth Restricted Optimum No. of Av. wt. Av. wt. Av. wt. No. of Av. wt. Av. wt. Av. wt. heifers weaning 15 mo. 2 yr. heifers weaning 15 mo. 2 yr. No. Lb. 5 422 1958________________________ 10 402 1959________________________ 7 407 1960 _______________________ 11 423 1961 _______________________ 1962 ____------------------12 452 TOTAL OR AV. Lb. 565 532 507 533 618 574 Lb. 766 763 739 851 757 780 No. 5 5 4 11 10 35 Lb. 380 345 336 412 388 383 Lb. 434 421 438 480 520 468 Lb. 659 694 726 794 716 730 Difference +106 +50i 1 Weight data for 2 years of age include the open heifers. TABLE 5. COMPARATIVE GROWTH RATES OF REPLACEMENT HEIFERS ON OPTIMUM AND RESTRICTED FEEDING' ---- +41 45 424 Cow age Optimum Restricted Difference Lb. 780 2 years______________________________ 865 3 years _______________________________ 942 4 years_______________________________ Lb. 730 810 901 Lb. 41 383 424 Weaning____________________________ 574 15 months -------------------------- 468 106 50 55 41 988 5 years_______________________________ 1,036 6 years_______________________________ 942 974 46 62 1Values shown are weighted means of all females at age indicated. pounds heavier at 2 years. However, it is noted that body weight data reported for 2 years of age included the open heifers. The apparent ability of the restricted-fed heifers to "catch up in body size between 15 months and 2 years is explained in part by the fact that only 50 per cent of this group calved at 2 years of age, as compared with 67 per cent of optimum heifers. Body weight data for replacement heifers at intervals until maturity (6 years) are reported in Table 5. These data indicate that at 5 or 6 years of age the difference. in body size was negligible and that the mature body size of the restricted-fed replacement females was not affected. The fact that the optimum-fed cows weaned an average of 4.16 calves during the study to the restricted cows 3.62 probably contributed to the lack of effect on mature body size. Also, the summer feeding level was adequate to allow some compensatory growth of the young, restricted-fed cows. Cows were heaviest in the fall, Table 6, and about 150 pounds lighter the following April 1, Table 7. All cows had access to quality pasture and regained winter weight loss by November 1. 12 12 TABLE ALABAMA AGRICULTURAL EXPERIMENT STATION ALABMA 6. AGRICULTURLEPIMN ST IO COW WEIGHTS ON NOVEMBER 1 ON OPTIMUM AND RESTRICTED FEEDING' Year born and Weight by age (years) 6 7 Lb. 1,103 feeding treatment 2 3 4 5 Lb. Lb. Lb. 1955-56 988 1,023 Optimum -------------- 1,036 Restricted -------------1,013 985 1,030 1956-57 956 999 Optimum---------------908 Restricted---------------. 938 941 1,030 1958-59 Optimum--------------780 894 949 ------- 867 892 Restricted ---------------1959-60 Optimum.-------------760 836 996 Lb. Lb. 999 1,142 1,0421,093 1,044 1,099 1,011 942 995 1,049 1,135 1,135 8 Lb. 1,143 1,115 9 Lb. 1,205 1,162 1,073 1,104 1,039 1,008 1,116 1,073 ----- - Restricted---------------. 1960-61 Optimum---------------Restricted---------------1961-62 Optimum .-----------Restricted---------------. 800 784 830 885 849 866 857 803 911 845 908 871 899 939 919 - 934 964 943 795 868 732 735 1Includes cows that had calved by November 1 and those that were pregnant; does not include open cows. ----------TABLE 7. COW WEIGHTS ON APRIL 1962-63 Optimum Restricted ------------1 ON OPTIMUM - --- - - AND RESTRICTED FEEDING' Year born and feeding treatment 1955-56 Optimum Weight by age 2 Lb. 891 797 3 Lb. 914 888 4 Lb. 918 883 5 Lb. 1,004 991 6 Lb. 1,041 926 7 Lb. 1,123 1,009 8 Lb. 1,173 1,100 Restricted ----1956-57 Restricted ----842 1958-59 Optimum ----- 841 896 876 822 705 942 977 916 793 969 902 1,004 863 1,041 993 1,058 1,049 --_-- Optimum------ 741 Restricted ----737 Optimum Restricted----- --- --- --- --- ----- 1959-60 1960-61 Optimum ----714 674 699 706 ----- 802 764 748 802 892 892 857 836 794 904 910 863 893 865 --- --------___ ----------- __- __- Restricted -----1961-62 Optimum --- ---------- ---_- 728 Restricted ----- ----800 744 621 ------ 792 828 ---- 1962-63 Optimum ----Restricted ----1Includes 794 732 ----- --- ----- ------- --- only cows with calves at side; open cows not included. EFFECT OF WINTER FEEDING LEVEL 13 Post-Weaning Steer Performance Steers from the two groups were combined after weaning and their post-weaning performance measured during a growing-finishing program. Cool-season annual grazing, such as oats and clover, followed by a drylot fattening period was the system used. The optimum steer calves were 44 pounds heavier at weaning, 39 pounds heavier at beginning of drylot fattening, and 43 pounds heavier at slaughter, Table 8. That the heavier calves maintained their weight advantage throughout the growing-finishing period is important to commercial cattlemen. TABLE 8. POST-WEANING RESTRICTED STEER PERFORMANCE 5-YEAR ON OPTIMUM MEANS AND FEEDING, WEIGHTED Performance measure Total number of steers ___ Optimum 55 Restricted 37 Difference 44* 39 43 Weaning weight, lb. 456 Begin feedlot weight, lb............ 772 . Final feedlot weight, lb............ 964 ** Highly significant (probability less than .01). 412 733 921 Reproductive Rate of 2-Year-Old Heifers All replacement heifers were exposed to breeding at 15 months of age for initial calving at approximately 2 years. Perhaps the most important result from the study was that 29 of 43 (67 per cent) optimum heifers raised in the study calved initially at 2 years of age, as compared with only 17 of 34 (50 per cent) of the restricted heifers, Table 9. Also, 53 per cent of the restricted-fed heifers that calved initially at 2 years of age failed to calve at 3 years. Among the optimum group, only 24 per cent that calved at 2 years failed to calve again at 3 years. Perhaps the most important implication of this result for the liveTABLE 9. CALVING RATE OF REPLACEMENT HEIFERS ON OPTIMUM AND RESTRICTED FEEDING Calving measurement Restricted Optimum Number Per cent Number Per cent 29/43 7/29 21/43 2/43 67 24 49 28 5 17/34 9/17 6/34 17/34 1/34 50 53 18 50 3- Chisquare probability <.12 <.01 <.01 <.02 Calved at 2 years Calved at 2 years-open at 3 years Calved at 2 and 3 yearsCalved at 3 years-open at 2 years __12/43 Open at 2 and 3 years...... - - 14 14 ALABAMA AGRICULTURAL EXPERIMENT TABLE 10. PER CENT CALVING BY Cow-AGE GROUPS ON OPTIMUM AND RESTRICTED STATION FEEDING Cow-age, years Optimum Number Per cent 4 6/60 48/61 52/60 4 4/48 77 Restricted Number Per cent 2 ---------------------------------------3 ---------------------------------------4 ---------------------------------------5 ---------------------------------------- 36/37 97 8/11 73 100 8/8 8--------------------------------------3/3 100 9--------------------------------------245/288 85 TOTAL ---------------------------2 + 3--------------------------------. 94/121 78 4-9 ---------------------------------151/167 90 6 ---------------------------------------7-- --------------------------------------- 79 87 92 33/49 36/48 42/48 34/39 67 75 88 87 26/28 910 / 6 /6 4 /4 93 90 100 100 82 190/232 121/135 69/97 71 90 stock producer is that 49 per cent of the better-fed heifers calved at both 2 and 3 years of age, but only 18 per cent of the restricted group, Table 9. The percentage of all optimum-fed and fed heifers calving at 3 years of age were 79 and 75, respectively, Table 10. restricted- Reproduction of All Cows This study was not designed to measure lifetime reproductive efficiency, but the data provide some information of interest. Similar calving rates of 85 and 82 per cent were obtained for optimum and restricted, respectively. These rates were definitely lowered by the poor performance of the 2- and 3-year-old cows that had calving rates of 78 per cent for the optimum and 71 per cent for the restricted. The overall calving percentage of cows 4 years and older was 90 per cent in both groups, Table 10. The year-to-year variation in percentage of cows calving was comparable for both groups except for 1960-61. During that year all of the better-fed cows conceived, but only 73 per cent of the restricted group. There is no obvious explanation for that year's difference. The most important measure of reproduction to the cattleman is the number of calves actually weaned. The optimum-fed cows weaned 234 calves out of a possible 288, or 81.25 per cent. Comparable values for restricted dams were 181 weaned out of a possible 232, or 78.02 per cent. These production differences were essentially differences in calving rate, since 95.5 per cent of the pregnant optimum-fed cows weaned a calf, as compared with 95.2 per cent of the restricted cows. EFFECT OF WINTER FEEDING LEVEL 15 Average calving dates ranged from October 29 to November 20, essentially the same for feeding treatments. Apparently treatments did not delay conception. Blood Composition Blood composition data for cows and their calves were collected during the 1960-61 winter test. Vitamin A, calcium, and phosphorus blood levels were all within the normal range for both cows and calves, Table 11 and 12. The hemoglobin level of the restricted-fed cows averaged below normal (12 g./100 ml. blood is considered normal). Hemoglobin levels of both groups of calves and the optimum-fed cows were essentially normal. TABLE 11. INFLUENCE OF WINTER RATION OF LACTATING BEEF COWS ON BLOOD CONSTITUENTS Constituent Optimum 2/17/61 3/31/61 Restricted' 2/17/61 3/31/61 52.37 449 9.96 9.88 5.99 42.992 Vitamin A, ug./100 ml..................... 69.34 112.06 Carotene, ug./100 ml. 641 573 Hemoglobin, g./100 cc.................... 13.90 12.42 Calcium, mg./100 cc. _................... 11.70 11.36 Phosphorus, mg./100 cc. 6.20 5.56 93 9.40 13.00 5.59 1 These cows were carried on a johnsongrass sod until February 17, but were then confined to a bare lot until March 31. 2 Probably reflects insufficient carotene intake. TABLE 12. INFLUENCE OF WINTER RATION OF LACTATING ON BLOOD CONSTITUENTS OF THEIR CALVES BEEF COWS Constituent Optimum 2/17/61 3/31/61 Restricted' 2/17/61 3/31/61 75.67 49.03 41.812 Vitamin A, ug./100 ml........... 42.68 140 2 571 472 631 Carotene, ug./100 ml. 13.60 11.46 13.70 Hemoglobin, g./100 cc. 11.26 Calcium, mg./100 cc. 11.86 12.90 10.84 13.70 Phosphorus, mg./100 cc. 8.95 9.08 8.49 9.08 1 The cows and their calves were on a johnsongrass sod until February 17 at which time they were moved to a bare lot until March 31. 2 Probably reflects insufficient carotene intake. The marginal level of protein intake (1.87 pounds crude protein daily) probably accounts for the low hemoglobin level in the restricted-fed cows. They recovered rapidly when turned on lush pasture April 1, and no clinical symptoms of anemia occurred. The milk protein probably contributed to the maintenance of the hemoglobin level of the restricted-fed calves. 16 TABLE 13. ALABAMA AGRICULTURAL EXPERIMENT STATION INFLUENCE OF LEVEL OF WINTER FEEDING ON MILK PRODUCTION OF BEEF COWS Year and feeding treatment 1958-59 Optimum ............ ---. Restricted ______________________3.47 12-hour FCM Start of winter, November 1 Lb. End of winter, April 1 Lb. 5.28 56 days after end of winter test Lb. 3.63 4.50 4.14 2.22 4.39 3.35 4.12 4.01 5.60 5.01 1959-60 Optimum .. Restricted 1960-61 Optimum Restricted - 5.35 5.18 6.31 5.64 Milk Production Cows were milked in an effort to determine effect of winter ration on milk production. All lactating females were milked at the beginning and end of the winter period and approximately 56 days later. The latter time was chosen to determine effect of lush pasture following the winter feeding treatments. Cows on both feeding treatments declined materially in milk production by the end of winter feeding (26.52 per cent for optimum and 48.87 per cent for restricted). However, restricted-fed cows responded when given access to lush spring pasture and, after 60 days on pasture, their milk production was equal to that of cows fed better during the winter, Table 13. A study of the composition of milk produced showed that it was low in dry matter and energy when cows were on the test winter rations, Table 14. However, both dry matter and energy increased when cows were shifted to good pasture. TABLE 14. DRY MATTER AND ENERGY CONTENT OF MILK PRODUCED DURING WINTER AND SPRING ON OPTIMUM AND RESTRICTED FEEDING Content measured, three dates No. of cows 2/17/61 3/30/61---------------..--5/26/61 DM content of milk, per cent 2/17/61 -12.47 3/30/61 5/26/61.. Energy value of FCM, C/lb. 2/17/61 3/30/61 5/26/61------ Optimum 17 17 15 14.65 13.39 312 332 340 Restricted 10 10 10 12.26 13.49 13.41 307 349 336 ... EFFECT OF WINTER FEEDING LEVEL TABLE 15. MILK PRODUCTION OF ORIGINAL AND RAISED ON OPTIMUM AND RESTRICTED FEEDING' 17 Cows Dates milked Optimum Restricted Cows raised Original cows Cows raised Original cows Cows 12-hr. Cows 12-hr. Cows 12-hr. Cows 12-hr. milked FCM milked FCM milked FCM milked FCM No. 1/29/64 4 / 1 / 64 Lb. No. Lb. No. Lb. No. 7 Lb. 4.66 ------ 24 5.19 ----------8 5.49 18 4.33 -------------------25 5.04 8 5.43 19 4.14 11/20/64 --------------19 6.44 13 5.52 ----------------------------- 7 -- 4.18 _ 4/1/65 1958-61 av. 11/1 -----------------25 4.89 ------------------------ 5.855.85 20 ---2.96 3.35 -- 5.36 4/1 56 days later ------------- _ 4.59 4.42_4.46 Hereford. 1'Replacement females were Angus-Hereford crosses, whereas original cows were Data in Table 15 show that females raised in this study produced slightly more milk than their dams at comparable age and feeding condition. Winter feeding had no permanent adverse effect on milk production. It is noted that the replacement males were Hereford-Angus crosses, whereas the original cows were Hereford. Evaluation of Weaned Calves fe- Calves were weaned within the week they reached 250 days of age. They were then evaluated for slaughter grade, stocker grade, and market price, Table 16. Calves from the optimum-fed dams had higher slaughter grades than those from restricted-fed cows, but stocker grades were not different. The 8-year average selling price per hundredweight was $24.51 for calves from optimum-fed dams and $24.08 for those from the restricted group. Since the optimum-fed dams weaned heavier calves, the 8-year average market value of their calves was $13.37 per head more than that of calves from restricted-fed dams, Table 16. 18 ALABAMA AGRICULTURAL EXPERIMENT STATION 18 ALABAMA AGRICULTURLEPRMN ON TTO TABLE 16. EVALUATION OF CALVES AT WEANING OPTIMUM AND RESTRICTED FEEDING Year born and feeding treatment No. of calves Adj. wl wt., lb. Slaughter Stocker Price 1 grade1 per cwt. grade 8.6 7.5 8.1 9.8 9.2 9.8 9.5 10.4 9.0 10.9 V 1958-59 14 Optimum __________________ Restricted__________________ 12 1959-60 Optimum 14 Restricted ._________________ 13 1960-61 Optimum _______________ 17 Restricted__________________ 10 1961-62 Optimum _______________ 27 Restricted _________________ 19 1962-63 Optimum ______________ 30 Restricted _________________ 21 1963-64 Optimum 488 449 400 476 430 475 445 504 436 485 10.7 10.3 11.1 $29.71 28.46 22.68 $145.56 128.13 105.53 464 8.9 -----------------11.0 12.0 11.8 11.8 11.9 12.3 11.6 11.8 24.12 24.68 24.25 25.47 25.25 25.03 25.10 21.80 95.97 117.41 104.81 121.06 112.79 126.26 109.21 105.83 --------- 33 Restricted _________ 1964-65 Optimum _________ Restricted _________ 1965-66 Optimum _________ Restricted _________ 8-year mean Optimum _________ Restricted-------1 2 25 26 20 23 17 184 137 461 476 425 504 450 486 439 10.6 10.4 9.4 11.4 9.6 10.21 9.30 11.4 12.2 11.4 13.1 11.6 11.99 11.42 21.45 23.01 21.92 26.07 24.68 24.51 24.08 99.07 110.33 93.56 131.19 111.21 119.27 105.90 9 - low Good, 10 - Good, 11 - high Good, 12= low Choice. Evaluation of market value or actual sale price. Acua weaning weight price shown. @ EFFECT OF WINTER FEEDING LEVEL 19 LITERATURE CITED (1) ANTHONY, W. B., P. F. PARKS, E. L. MAYTON, V. L. BROWN, J. G. STARLING, AND T. B. PATTERSON. 1959. A New Technique for Securing Milk Production Data for Beef Cows Nursing Calves. J. An. Sci. 18:1541. (2) 1944. Comparison of Different Amounts of Protein Supplement for Wintering Beef Cows on Forest Range in the Southeastern Coastal Plain. J. An. Sci. 3:436. FOSTER, J. E., H. H. BISWELL, AND E. H. HOSTETLER. HAMMES, R. C., JR., R. E. BLASER, C. M. KINCAID, H. T. BRYANT, AND (3) (4) (5) (6) R. W. ENGEL. 1959. Effects of Full and Restricted Winter Rations on Dams and Summer-Dropped Suckling Calves Fed Different Rations. J. An. Sci. 18:21. PINNEY, DON, L. E. MALKUS, L. S. POPE, AND K. URBAN. 1962. Effect of Preweaning Plane of Nutrition on Subsequent Feedlot Performance and Carcass Composition of Beef Calves. J. An. Sci. 21:388. 1963. Accumula- , L. S. POPE, AND D. F. STEPHENS. tive Effects of Winter Feeding Regimes on Mature Size and Reproduction in Beef Females. J. An. Sci. 22:843. SMITH, L. A. AND H. W. GRIMES. 1958. Summary of Some Experi- ments at the Black Belt Substation. Mimeograph. (7) ZIMMERMAN, Auburn Univ. Agr. Exp. Sta. F. STEPHENS. J. E., L. S. POPE, AND D. 1958. Effect of Level of Wintering Upon the Growth and Reproductive Performance of Beef Heifers. J. An. Sci. 17:1196. AGRICULTURAL EXPERIMENT STATION SYSTEM OF ALABAMA'S LAND-GRANT UNIVERSITY 3 1 Un('5(0? t illit II (5 I 1 seI , r Stock. Iolorsti Itor , and i ticltut iii producers in each rgiooi in \a b1a1 a. Cix'r citizen of the State has a stake ill this rese s~u-ch pro null, 1 siiicc ally, a~d\antiwe ® 12 rG L 14 - 5I econuomiiical \ways of 1 .l I r-' L j)odcil and handling farm produ"'lcts dlircok beneicfits the cornsuntin"ill Research Unit Identification Tennessee Valley Substation, Belie Mina Sand Mountain Substation, Crossvilla North Alabama Horticulture Substation, Cullman Upper Coastal Plain Substotion, Winfield. Forestry Unit, Fayette County. Thorsby Foundation Seed Stocks Farm, Thorsby. Chilton Area Horticulture Substation, Clanton. Forestry Unit, Coosa County Piedmont Substation, Camp Hill. Plant Breeding Unit, Tallassee Forestry Unit, Autauga County. Prattville Experiment Field, Prattville. Black Belt Substation, Marion Junction. Tuskegee Experiment Field, Tuskegee. Lower Coastal Plain Substation, Camden. 16. Forestry Unit, Barbour County. 17. Monroeville Experiment Field, Monroeville. 18. Wiregrass Substation, Headland. 19. Brewton Experiment Field, Brewton. 20. Ornamental Horticulture Field Station, Spring Hill 21. Gulf Coast Substation, Fairhope. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15