Deetz L E, Richardson C R, Pritchard R H, Preston R L
J Anim Sci. 1985 Dec;61(6):1539-49. doi: 10.2527/jas1985.6161539x.
Two trials were conducted to study the effects of feeding a mixture of ammonium salts of isovaleric, 2-methylbutyric, isobutyric and valeric acids (AS-VFA) on feedlot performance and carcass characteristics of growing and finishing Angus, Hereford and Angus X Hereford steers. In trial 1,192 steers (8 steers/pen, 6 pen/treatment) averaging 251 kg body weight and in trial 2, 240 steers (8 steer/pen, 7 pens/treatment, 9 pens/control treatment) averaging 216 kg body weight were randomly assigned to four anhydrous ammonium salt-volatile fatty acid (AS-VFA) treatment levels: 0 (control), .14, .28 and .42% of the diet dry matter (DM). In each trial, the growing and finishing diets were isocaloric, isonitrogenous and supplemented with monensin (26 mg/kg diet). In both trials, steers received implants of 200 mg progesterone and 20 mg estradiol benzoate. Combined data from the trials confirmed the absence of average daily gain and feed conversion responses during the growing period. During the finishing period, the combined data for gain and feed conversion for the control steers and the steers fed .14, .28 and .42% AS-VFA were 1.43, 7.09; 1.43, 6.99; 1.48, 6.67 and 1.45, 6.80, respectively. Gains increased 3.5% (P less than .10) and feed conversion improved 5.9% (P less than .07) in steers fed .28% AS-VFA compared with gain and feed conversion of the control steers. At the end of the growing period in the first trial, a urea dilution technique was used to estimate the body composition of 12 steers from each treatment. Estimates of percent body fat and percent body protein were similar (P greater than .20) for all steers, irrespective of treatment. At the end of the trials, carcass yield grades for the combined data were 2.6 and 2.8 (P less than .10) for steers fed .28% AS-VFA and for the control steers, respectively. Carcass weight, dressing percentage and marbling score were lower (P less than .10) in steers fed AS-VFA than for steers fed the control. However, in general, carcass characteristics were not greatly influenced by AS-VFA. A possible use for a supplement containing branched-chain fatty acids and valeric acid in finishing steer diets is suggested by the improvement in feedlot performance and by the slight increase in carcass yield.
进行了两项试验，以研究饲喂异戊酸、2-甲基丁酸、异丁酸和戊酸的铵盐混合物（AS-VFA）对生长育肥期安格斯牛、赫里福德牛以及安格斯×赫里福德杂交阉牛的育肥性能和胴体特性的影响。在试验1中，192头阉牛（每栏8头，每个处理6栏），平均体重251千克；在试验2中，240头阉牛（每栏8头，每个处理7栏，对照处理9栏），平均体重216千克，被随机分配到四种无水铵盐-挥发性脂肪酸（AS-VFA）处理水平：0（对照）、0.14%、0.28%和0.42%的日粮干物质（DM）。在每项试验中，生长育肥日粮能量相等、含氮量相等，并添加莫能菌素（26毫克/千克日粮）。在两项试验中，阉牛均植入200毫克孕酮和20毫克苯甲酸雌二醇。试验合并数据证实，生长期间平均日增重和饲料转化率没有变化。育肥期，对照阉牛以及饲喂0.14%、0.28%和0.42% AS-VFA阉牛的增重与饲料转化率合并数据分别为1.43、7.09；1.43、6.99；1.48、6.67和1.45、6.80。与对照阉牛相比，饲喂0.28% AS-VFA的阉牛增重提高3.5%（P＜0.10），饲料转化率提高5.9%（P＜0.07）。在第一项试验的生长期末，采用尿素稀释技术估计每个处理12头阉牛的身体组成。所有阉牛的体脂百分比和体蛋白百分比估计值相似（P＞0.20），与处理无关。试验结束时，合并数据的胴体产量等级中，饲喂0.28% AS-VFA的阉牛和对照阉牛分别为2.6和2.8（P＜0.10）。饲喂AS-VFA的阉牛胴体重、屠宰率和大理石花纹评分低于对照阉牛（P＜0.10）。然而，总体而言，胴体特性受AS-VFA的影响不大。育肥阉牛日粮中含支链脂肪酸和戊酸的补充剂的一种可能用途，是基于育肥性能的改善和胴体产量的轻微提高而提出的。
