Kemp J D, Vimini R J, Ely D G
Dept. of Anim. Sci., University of Kentucky, Lexington 40546-0215.
J Anim Sci. 1988 Dec;66(12):3073-85. doi: 10.2527/jas1988.66123073x.
Pregnant ewes (large frame [LF] and small frame [SF]) were nutritionally stressed in early gestation (EGS), late gestation (LGS) or fed 100% of NRC requirements (unstressed, US) throughout gestation. Lambs (128) from these ewes were slaughtered at birth, weaning (18 kg), 41 kg or 55 kg. Sixty-four lambs received a 13% protein diet from weaning to either 41 or 55 kg. Lambs from SF ewes were fatter at 55 kg, had a higher numerical yield grade and a lower percentage of carcass protein. Lambs from US ewes were youngest at slaughter and had the most carcass weight and protein per day of age at 55 kg. The LGS lambs had the lowest percentage of lean and carcass protein at 41 and 55 kg. However, at birth these lambs had the highest concentration of RNA and DNA in muscle. The EGS lambs had the lowest quality grade, carcass weight per day of age and fat percentage. Muscle DNA and RNA at birth was lowest in EGS lambs. However, EGS lambs produced the highest lean percentage and highest percentage carcass protein at 41 and 55 kg. Shortest metacarpals and metatarsals were also found in these lambs at weaning and 41 kg. Although frame size had little effect on carcass characteristics, the effects of nutritional stress in the first 80 d of gestation were apparent in lambs slaughtered at 31 kg. Stress in the last 50 d of gestation had more effect on lambs slaughtered at 55 kg.
妊娠母羊（大体型[LF]和小体型[SF]）在妊娠早期（EGS）、晚期（LGS）受到营养应激，或在整个妊娠期饲喂100%美国国家研究委员会（NRC）推荐量的饲料（无应激，US）。这些母羊所产的128只羔羊在出生时、断奶时（体重18千克）、41千克或55千克时屠宰。64只羔羊从断奶到体重达到41千克或55千克期间饲喂13%蛋白质的日粮。55千克时，SF母羊所产羔羊更肥，产量等级数值更高，胴体蛋白质百分比更低。US母羊所产羔羊屠宰时年龄最小，55千克时每单位年龄的胴体重量和蛋白质含量最高。41千克和55千克时，LGS羔羊的瘦肉和胴体蛋白质百分比最低。然而，出生时这些羔羊肌肉中的RNA和DNA浓度最高。EGS羔羊的品质等级最低，每单位年龄的胴体重量和脂肪百分比最低。EGS羔羊出生时肌肉中的DNA和RNA含量最低。然而，EGS羔羊在41千克和55千克时瘦肉百分比和胴体蛋白质百分比最高。在断奶时和41千克时，这些羔羊的掌骨和跖骨也是最短的。尽管体型大小对胴体特征影响不大，但妊娠前80天的营养应激对31千克时屠宰的羔羊影响明显。妊娠最后50天的应激对55千克时屠宰的羔羊影响更大。
