MOLASSES AND COTTONSEED MEAL SUPPLEMENTATION OF AMMONIATED HAY FOR YEARLING CATTLE

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1 MOLASSES AND COTTONSEED MEAL SUPPLEMENTATION OF AMMONIATED HAY FOR YEARLING CATTLE SUMMARY W.F. Brown Two growth trials were conducted to evaluate the effects of molasses and/or cottonseed meal supplementation of ammoniated stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) hay on the performance of yearling cattle. Ammoniation increased the crude protein concentration and reduced the neutral detergent fiber (NDF) concentration of the stargrass hay. In vitro digestion of organic matter, NDF and acid detergent fiber were greater in ammoniated compared to untreated hay. In trial 1, Brahman-crossbred steers (510 lb) were fed ad libitum amounts of ammoniated hay plus the following supplements: (1) control, (2) 4.2 lb standard molasses per day, (3) 1.0 lb cottonseed meal per day, and (4) 3.0 lb standard molasses plus 1.0 lb cottonseed meal per day. In trial 2, Brahmancrossbred steers (480 lb) were fed ad libitum amounts of ammoniated hay plus the following supplements: (1) control, (2) ad libitum amounts of standard molasses, (3) 1.25 lb cottonseed meal per day, and (4) ad libitum amounts of standard molasses plus 1.25 lb cottonseed meal per day. Calves fed ammoniated hay alone gained.4 to.5 lb per day. Supplementation with molasses or cottonseed meal increased daily gain to approximately 1.0 lb. Ad libitum molasses consumption in trial 2 was 5.9 lb per day for the molasses alone treatment, and was increased to 7.0 lb per day when it was mixed into a slurry with cottonseed meal. Daily gain for calves fed ammoniated hay supplemented with molasses supplemented with cottonseed meal was 1.2 lb in trial 1 and 1.7 lb in trial 2. Cost of gain for calves fed ammoniated hay supplemented with molasses plus cottonseed meal was $.63 in trial 1 and $.53 in trial 2. Ammoniated hay supplemented with molasses plus cottonseed meal can provide a winter feeding program that will develop a 500 lb heifer during her first winter after weaning so that she will be ready to breed to calve at two years of age. INTRODUCTION During the winter, most Florida cattle producers feed lactating cows and developing heifers low quality hay or stockpiled bahiagrass (Paspalum notatum) pasture plus a molasses-urea supplement. Historically this feeding program has not provided the nutrition necessary for desired calving rates or adequate heifer development. Florida ranks as one of the three lowest states in the nation in weaned calf crop (70%), and most heifers calve for their first time at three rather than two years of age. A primary reason for poor growth and reproduction rates is low forage (stockpiled pasture, hay) quality and quantity during the winter months. Most hay is too mature when harvested leading to low crude protein and energy values and low intake by cattle. Feeding value of this low quality hay can be improved by treating it with anhydrous ammonia Another report in this publication (Brown, pg 58) showed that ammoniated hay provided a level of animal performance that was at least equal to that provided by untreated hay plus a molasses-urea supplement. However a question still remains as to whether this level of animal performance is adequate to breed heifers at two years of age. The objectives of this research were to improve performance of cattle fed ammoniated hay by supplementing it with standard molasses and/or cottonseed meal.

2 MATERIALS AND METHODS Forage Treatment and Analysis. In each of two years (1987 and 1988), mature growth of stargrass was harvested and stored as hay in approximatley 750 lb round bales. In each year three stacks of 90 bares each were treated with anhydrous ammonia at the rate of 4% of the forage dry matter following procedures described earlier in this publication(brown and Johnson, pg 50). Ammoniated hay was covered for approximately 1 month, then uncovered and aerated. Untreated hay was sampled prior to ammoniation, and ammoniated hay was sampled after ammoniation. Hay samples were dried, ground and the following laboratory analyses conducted: crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL). In vitro digestion of organic matter (OM), NDF and ADF, and in vitro rate and extent of NDF digestion were also measured. Growth Trials. In trial 1, after weaning in September 1987, 96 Brahman crossbred steers averaging 510 lb were randomly allotted to 12 groups of 8 head each. Three groups were assigned to one of the following four treatments: (1) ammoniated hay alone (2) ammoniated hay plus 4.2 lb/head/day of standard molasses (3) ammoniated hay plus 1.0 lb/head/day of cottonseed meal (4) ammoniated hay plus 3.0 lb/head/day of standard molasses plus 1.0 lb/head/day of cottonseed meal. Supplements 2 and 4 were calculated to be equal in total digestible nutrients (TDN) assuming equal TDN between molasses and cottonseed meal. In trial 2, after weaning in September 1988, 96 Brahman crossbred steers averaging 480 lb were randomly allotted to 12 groups of 8 head each. Three groups were each assigned to one of the following four treatments: (1) ammoniated hay alone (2) ammoniated hay plus ad libitum amounts of standard molasses (3) ammoniated hay plus 1.25 lb/head/day of cottonseed meal (4) ammoniated hay plus ad libitum amounts of standard molasses plus 1.25 lb/head/day of cottonseed meal. In each trial, each group of steers was placed on a 2.5 acre bahiagrass pasture. Cattle remained in their respective pastures during the entire trial. The same pastures were used in both trials. Steers were fed ad libitum quantities of ammoniated hay in round bale feeders. All hay was weighed before feeding. Hay not consumed at the end of the trial was weighed and there was minimal waste. Supplements were fed in open troughs three times weekly. For the ammoniated hay supplemented with molasses plus cottonseed meal diets, molasses and cottonseed meal were mixed into a slurry. In trial 1, all supplements were completely

3 consumed. In trial 2, for diets containing molasses, molasses was added as needed so that there was molasses available at all times. A commercial mineral mix was fed free choice. RESULTS AND DISCUSSION In each year, untreated stargrass hay was low in nutritive value as reflected by its low CP and high NDF content, and low in vitro digestion of OM, NDF and ADF (Tables 1 and 2). This was typical of stargrass hay we receive from livestock producers in our extension forage testing program. Ammoniation increased CP concentration of the stargrass hay (Table 1). Approximately 40% of the CP present in the untreated hay was bound to the NDF fraction. Quantities of CP bound to the NDF and ADF were increased in the ammoniated hay. Arnmoniation reduced NDF concentration, with no change in ADF or ADL concentrations of the stargrass hay. In vitro digestion of OM, NDF and ADF were increased by ammoniation of stargrass hay (Table 2). Ammoniation did not influence digestion rate of the potentially digestible NDF fraction, while 96 hr extent of NDF digestion was increased by 31 to 40%. Growth Trials. In both trials, calves fed ammoniated hay alone consumed large quantities of hay (approximately 2.5% of body weight). In trial 1 (Table 3), supplementation with molasses and/or cottonseed meal only slightly reduced (P <.10) hay intake, while in trial 2 (Table 4) hay intake was reduced to a large degree (P<.05) by molasses supplementation. In trial 2, ad libitum molasses consumption was 5.9 lb per day (Table 4). Addition of cottonseed meal to the molasses to form a slurry resulted in an increase in molasses intake to 7.0 lb per day. Increased molasses consumption by the addition of a dry feed has also been observed with other feed ingredients. In both trials (Tables 3 and 4), total feed intake was similar between the nonsupplemented diet and the cottonseed meal supplemented diet. In trial 1 (Table 3) molasses intake was additive to hay intake, resulting in greater total feed intake for diets supplemented with molasses or molasses plus cottonseed meal compared to the nonsupplemented diet. In trial 2 (Table 4) molasses intake from the molasses only supplemented diet equally replaced the reduction in hay intake, resulting in equal total intake between the molasses only supplemented diet and the nonsupplemented diet. In trial 2, supplementation with molasses plus cottonseed meal resulted in greater total intake compared to the other diets. Calves fed ammoniated hay only gained from.4 to.5 lb per day (Tables 3 and 4). This level of animal performance is similar to that which we have obtained from feeding untreated hay plus ad libitum amounts of a molasses-urea supplement. This level of performance is probably not adequate to develop a 550 lb heifer during the approximate 5 month period from weaning until she should be exposed to a bull in order to calve at two years of age. It is for this reason that energy and protein supplementation of ammoniated hay was investigated. In both trials, (Tables 3 and 4) supplementation with standard molasses alone improved daily gain compared to the unsupplemented control. In trial 2 (Table 4), ad libitum molasses consumption was 5.9 lb per day, while molasses intake was restricted to 4.2 lb per day in trial 1 (Table 3). Ammoniated hay intake was reduced by molasses supplementation in teal 2, but not in trial 1. Efficiency of total dietary TDN utilization in the molasses alone supplemented diets was slighty greater in trial 1 where the smaller amount of supplemental molasses was consumed.

4 In both trials (Tables 3 and 4) supplementation with cottonseed meal improved daily gain compared to the unsupplemented control. In both trials, crude protein concentration of the ammoniated hay (10.8 and 11.6%) was adequate to meet the protein requirements of the animals based upon published National Research Council requirements. A portion of the increased daily gain by cottonseed meal supplementation was due to the TDN in the cottonseed meal. Assuming that the TDN in molasses and cottonseed meal is the same and is utilized to the same degree, the added gain above the control due to TDN in the cottonseed meal was approximately.10 lb. per day. This means that of the observed.5 lb per day increase in daily gain by cottonseed meal supplementation above the control,.4 lb per day was due to the natural protein in the cottonseed meal stimulating microbial protein production in the rumen and/or bypassing degradation in the rumen and providing amino acids for absorption in the small intestine. Supplementation with molasses plus cottonseed meal resulted in a further increase in daily gain compared to supplementation with molasses or cottonseed meal alone (Tables 3 and 4). In both trials, the response to molasses plus cottonseed meal supplementation was additive indicating that the cattle responded to both energy and protein supplementation. The daily gains obtained by molasses plus cottonseed meal supplementation of ammoniated hay in these trials (1.2 and 1.7 lb per day) are adequate to develop 500 lb heifers so that they will be ready to breed at approximately 15 months of age. Considering both trials, cost of the added gain above the control was similar for the three supplementation treatments (Tables 3 and 4). However cost of gain was cheaper for cottonseed meal compared to molasses supplementation. Cost of gain for molasses plus cottonseed meal supplementation of ammoniated hay was cheapest and is very competitive compared to other options for winter feeding of calves. CONCLUSIONS Calves fed ammoniated hay alone gained.4 to.5 lb per day. This forms a base to which supplementation programs can be applied. Both molasses alone and cottonseed meal alone supplementation of ammoniated hay improved daily gain compared to the unsupplemented control. Cattle fed ammoniated hay plus molasses plus cottonseed meal had the greatest daily gain. And the response to protein and energy were additive because the daily gain obtained by cattle supplemented with molasses plus cottonseed meal was greater than that predicted by TDN intake only. A winter feeding program of ammoniated hay supplemented with molasses plus cottonseed meal provides an economical level of animal performance that would be appropriate to develop 500 lb heifers so that they will be ready to breed so that they will calve at 2 years of age.

5 TABLE 1. CHEMICAL COMPOSITION OF UNTREATED AND AMMONIATED STARGRASS a HAY Year 1 Year 2 Item b Untreated Ammoniated SE c p d Untreated Ammoniated SE c p d % % CP NDF-CP ADF-CP NDF ADF ADL a Cynodon nlemfuensis Vanderbilt var. nlemfuensis. b CP = crude protein (DM basis), NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin(ash free, organic matter basis) c Standard error of the mean d Probability Value TABLE 2. IN VITRO DIGESTION OF UNTREATED AND AMMONIATED STARGRASS a HAY Year 1 Year 2 Item b Untreated Ammoniated SE c p d Untreated Ammoniated SE c p d IVOMD, % hr NDF diges tion, % 48 hr ADF diges tion, % Rate of NDF diges tion, %/hr 96 hr NDF diges O tion extent,% a Cynodon nlemfuensis Vanderyst var. nlernfuensis. b IVOMD = in vitro organic matter digestion, NDF = neutral detergent fiber, ADF = add detergent fiber(ash free organic matter basis). c Standard error of the mean. d Probability value.

6 TABLE 3. GROWTH PERFORMANCE OF YEARLING STEERS FED AMMONIATED STARGRASS. HAY SUPPLEMENTED WITH STANDARD MOLASSES AND/OR COTTONSEED MEAL (TRIAL 1) Treatment Ammoniated Ammoniated Ammoniated Ammoniated hay + molasses Item b hay alone hay + molasses hay + CSM + CSM SE c Intake, lb as-is Hay l4.9 d l4.3 d l4.6 d 14.1 d.84 Standard molasses Cottonseed meal Total intake, lb DM 13.1 d 15.7 e l3.7 d 15.5 e.71 Daily gain, lb.4 d.8 e.9 e 1.2 f.08 Cost of added gain g,$ Cost of gain g,$ a Cynodon nlemfuensis Vanderyst var. nlemfuensis. b DM = dry matter, CSM = cotton seed meal. c SE = standard error of the mean. d,e,f means In the same row without a common superscript are different (P<.05). g Ammoniated hay = $50/ton, standard molasses = $70/ton, cottonseed meal = $300/ton, yardage = $.15 per head per day. TABLE 4. GROWTH PERFORMANCE OF YEARLING STEERS FED AMMONIATED STARGRASS. HAY SUPPLEMENTED WITH STANDARD MOLASSES AND/OR COTTONSEED MEAL (TRIAL). Treatment Ammoniated Ammoniated Ammoniated hay + moles- Ammoniated hay + molas- Item b hay alone ses hay + CSM ses + CSM SE c Intake, lb as-is Hay 14.4 e l0.0 d 13.4 d l2.2 d.86 Standard molasses Cottonseed meal Total intake, lb DM 12.8 d 3.3 d l3.0 d 17.2 e.84 Dalb gain, lb.5 d.8 e 1.0 e 1.7 f.09 Cost of added gains g,$ Cost of gain g $ a Cynodon nlemfuensis Vandergst var. nlemfuensis. b DM = dry matter, CSM = cottonseed meal. c SE = standard error of the mean. d,e,f means in the same row without a common superscript are different (P <.05). g Ammoniated hay= S50/ton,standardmoiasses = S70/ton,cottonseed meal = S300/ton,yardage = $.15