安格斯牛、婆罗门牛及其正反交母牛所产犊牛在断奶后采食感染内生菌的高羊茅或普通狗牙根时的生产性能。

Postweaning performance of calves from Angus, Brahman, and reciprocal-cross cows grazing endophyte-infected tall fescue or common bermudagrass.

作者信息

Brown M A, Phillips W A, Brown A H, Coleman S W, Jackson W G, Miesner J R

机构信息

USDA-ARS, Grazinglands Research Laboratory, El Reno, OK 73036, USA.

出版信息

J Anim Sci. 1999 Jan;77(1):25-31. doi: 10.2527/1999.77125x.

DOI:10.2527/1999.77125x

PMID:10064024

Abstract

Data from 403 Polled Hereford-sired calves from Angus, Brahman, and reciprocal-cross cows were used to evaluate the effects of preweaning forage environment on postweaning performance. Calves were spring-born in 1991 to 1994 and managed on either endophyte-infected tall fescue (E+) or common bermudagrass (BG) during the preweaning phase. After weaning, calves were shipped to the Grazinglands Research Laboratory, El Reno, OK and stratified to one of two winter stocker treatments by breed and preweaning forage; stocker treatments were winter wheat pasture (WW) or native range plus supplemental CP (NR). Each stocker treatment was terminated in March, calves grazed cool-season grasses, and calves were then moved to a feedlot phase in June. In the feedlot phase, calves were fed to approximately 10 mm fat over the 12th rib and averaged approximately 115 d on feed. When finished, calves were weighed and shipped to Amarillo, TX for slaughter. Averaged over calf breed group, calves from E+ gained faster during the stocker phase (P<.10), had lighter starting and finished weights on feed (P< .01), lighter carcass weights (P<.01), and smaller longissimus muscle areas (P<.05) than calves from BG. Calves from E+ were similar to calves from BG in feedlot ADG, percentage kidney, heart, and pelvic fat, fat thickness over 12th rib, yield grade, marbling score, and dressing percentage. Maternal heterosis was larger in calves from E+ for starting weight on feed (P<.01), finished weight (P<.10), and carcass weight (P<.16). These data suggest that few carryover effects from tall fescue preweaning environments exist, other than lighter, but acceptable, weights through slaughter. These data further suggest that the tolerance to E+ in calves from reciprocal-cross cows, expressed in weaning weights, moderated postweaning weight differences between E+ and BG compared to similar comparisons in calves from purebred cows.

摘要

利用来自安格斯牛、婆罗门牛以及正反交母牛所产的403头无角海福特公牛犊的数据，来评估断奶前草料环境对断奶后生长性能的影响。犊牛于1991年至1994年春季出生，在断奶前阶段饲养于内生真菌感染的高羊茅（E+）或普通狗牙根（BG）草地上。断奶后，犊牛被运至俄克拉何马州埃尔里诺的放牧地研究实验室，并根据品种和断奶前草料被分层至两种冬季育肥牛处理之一；育肥牛处理为冬小麦牧场（WW）或天然牧场加补充粗蛋白（NR）。每种育肥牛处理在3月结束，犊牛采食冷季草，然后在6月进入育肥阶段。在育肥阶段，犊牛被饲喂至第12肋骨处脂肪厚度约为10毫米，平均育肥期约115天。结束时，对犊牛称重并运往得克萨斯州阿马里洛进行屠宰。在犊牛品种组中进行平均，与来自BG的犊牛相比，来自E+的犊牛在育肥牛阶段生长更快（P<0.10），育肥开始和结束时体重更轻（P<0.01），胴体重更轻（P<0.01），背最长肌面积更小（P<0.05）。来自E+的犊牛在育肥期平均日增重、肾、心和骨盆脂肪百分比、第12肋骨处脂肪厚度、产肉等级、大理石花纹评分和屠宰率方面与来自BG的犊牛相似。在来自E+的犊牛中，母体杂种优势在育肥开始体重（P<0.01）、结束体重（P<0.10）和胴体重（P<0.16）方面更大。这些数据表明，除了直至屠宰时体重较轻但仍可接受外，高羊茅断奶前环境几乎没有残留影响。这些数据进一步表明，与纯种母牛犊牛的类似比较相比，正反交母牛犊牛对E+的耐受性（以断奶体重表示）缓和了E+和BG犊牛断奶后的体重差异。