Brown D L, Dally M R, Schwartz M R, Bradford G E
Anim. Sci. Dept., University of California, Davis 95616.
J Anim Sci. 1987 Sep;65(3):692-8. doi: 10.2527/jas1987.653692x.
Lactation and growth of three contemporary lines of grade Targhee sheep developed from the same genetic base were characterized by three experiments performed over a period of 2 yr. Two lines (HW and DH) had been selected for 120-d weaning weights for 24 yr prior to beginning these experiments. A third line (C) was a randomly selected control. Year I experiment contrasted 10 DH with 7 C ram lambs fed to 58 kg. Year II experiments utilized 9 C, 14 DH and 10 HW ram lambs and 11 ewes suckling twins from each line. All Year II ram lambs were born and weaned as twins, then fed to 50 kg. Mature DH and HW ewes were heavier (P less than .05) than C ewes (65.2 and 68.8 vs 54.9 kg), and the DH and HW lambs grew faster than C lambs both before (P less than .05) and after weaning (P less than .05). While both DH and HW lambs drank more milk (2,419 and 2,368 vs 2,059 g X d-1 X pair-1; P less than .10) only HW ewes showed a trend towards greater potential milk production than controls (HW = 2,774 vs C = 2,155 g X d-1 X ewe-1 P less than .12). The HW lambs tended to be leaner than C lambs (P less than .05), but DH lambs did not differ from either line. Lambs from DH and HW lines required less post-weaning feed (121.9 and 129.3 vs 152.0 kg P less than .05) and exhibited 17 and 16% greater weight per day of age at 50 kg than controls (P less than .05). The DH line displayed lower feed: gain ratios than controls in both post-weaning trials (6.68 vs 7.30 to 58 kg; 5.83 vs 6.24 at 50 kg; P = .06).
在2年时间里进行了三项实验，对源自相同基因库的三个当代品系的塔吉羊的泌乳和生长特性进行了研究。在开始这些实验之前，两个品系（HW和DH）已经针对120日龄断奶体重进行了24年的选育。第三个品系（C）是随机选择的对照。第一年的实验对比了10只DH公羊羔羊和7只C公羊羔羊，饲养至58千克。第二年的实验使用了9只C、14只DH和10只HW公羊羔羊，以及来自每个品系的11只哺乳双胞胎的母羊。第二年所有的公羊羔羊均作为双胞胎出生并断奶，然后饲养至50千克。成熟的DH和HW母羊比C母羊更重（P小于0.05）（65.2千克和68.8千克对54.9千克），并且DH和HW羔羊在断奶前（P小于0.05）和断奶后（P小于0.05）都比C羔羊生长得更快。虽然DH和HW羔羊都喝了更多的奶（2419克和2368克对2059克×天⁻¹×对⁻¹；P小于0.10），但只有HW母羊显示出比对照有更大产奶潜力的趋势（HW = 2774克对C = 2155克×天⁻¹×母羊⁻¹；P小于0.12）。HW羔羊往往比C羔羊更瘦（P小于0.05），但DH羔羊与其他两个品系没有差异。DH和HW品系的羔羊断奶后所需饲料较少（121.9千克和129.3千克对152.0千克；P小于0.05），并且在50千克时每日龄体重比对照分别高17%和16%（P小于0.05）。在两次断奶后的试验中，DH品系的饲料增重比均低于对照（至58千克时为6.68对7.30；50千克时为5.83对6.24；P = 0.06）。
