USDA, ARS, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE.
Department of Animal Science, University of Wyoming, Laramie, WY.
J Anim Sci. 2019 Apr 3;97(4):1568-1577. doi: 10.1093/jas/skz070.
Though lamb sales account for the majority of annual receipts on U.S. sheep operations, wool is an important income source for many Western flocks. Crossing fine-wool sheep with prolific or composite hair sheep breeds can increase lamb production, but fleece quality and marketability may be reduced by a greater content of nonwool fibers (e.g., med and kemp). The objectives of this study were to compare BW and wool characteristics of Rambouillet, Polypay, and Romanov-White Dorper × Rambouillet (RW-RA) ewes under extensive rangeland management conditions. Ewe BW was collected before mating (fall) and 30 d postlambing (spring) each year from 1 yr up to 4 yr of age. In spring and fall, Rambouillet and Polypay ewes were similar in BW (P ≥ 0.94). Spring BW did not differ (P = 0.13) between RW-RA and Polypay, but Rambouillet ewes were heavier than RW-RA in the spring (P = 0.02). Both Rambouillet and Polypay ewes were heavier (P < 0.07) than RW-RA in the fall. Greasy fleece weight and mid-side wool samples were collected from ewes at 1 and 4 yr of age. Clean fleece weights (CFW) were estimated from average laboratory scoured yield of mid-side wool samples composited within-breed. Average fiber diameter (AFD), SD of fiber diameter (SD-FD), and percentage med (%M), kemp (%K), and total medullated fibers (%T) were quantified on individual mid-side wool samples. There was no difference in 1-yr-old CFW among breed types (P ≥ 0.96). Four-yr-old Rambouillet ewes had heavier CFW (2.29 kg; P < 0.001) than 4-yr-old Polypay (1.83 kg) and RW-RA ewes (1.86 kg), which were not different (P > 0.99). Within 1- and 4-yr-olds, AFD differed among breed type (P < 0.001) and was the finest for Rambouillet (20.1 and 21.9 µm, respectively), intermediate for RW-RA (22.8 and 24.8 µm), and coarsest for Polypay (24.2 and 26.7 µm). Also within 1- and 4-yr olds, SD-FD was lowest in Rambouillet, intermediate in Polypay, and greatest in RW-RA (P < 0.01). Wool from RW-RA ewes had greater %M, %K, and %T (P < 0.001) than wool from Rambouillet and Polypay ewes, which were not different (P > 0.99). Results indicated superior wool production for Rambouillet compared with the coarser, more variable wool produced by Polypay and RW-RA. Still, past research reported greater lamb production in Polypay and RW-RA ewes which, under recent market conditions, would be associated with greater annual gross revenue for these breed types than for Rambouillet.
尽管羊肉销售占美国绵羊养殖场年收入的大部分，但羊毛仍是许多西方羊群的重要收入来源。将细毛绵羊与多产或复合毛绵羊品种杂交可以增加羔羊产量，但由于非羊毛纤维（如中等纤维和马海毛）含量增加，羊毛品质和市场性可能会降低。本研究的目的是比较在广泛的牧场管理条件下，雷蒙达、波尔派和罗曼诺夫-白多伯×雷蒙达（RW-RA）母羊的体重和羊毛特性。在每年 1 至 4 岁时，在配种前（秋季）和产后 30 天（春季）收集母羊的体重。在春季和秋季，雷蒙达和波尔派母羊的体重相似（P≥0.94）。RW-RA 和波尔派之间的春季 BW 没有差异（P=0.13），但雷蒙达母羊的 BW 比 RW-RA 重（P=0.02）。在秋季，雷蒙达和波尔派母羊的体重均高于 RW-RA（P<0.07）。在 1 岁和 4 岁时，从母羊身上采集油腻的羊毛重量和中侧羊毛样本。从品种内的中侧羊毛样本的平均实验室洗净产量估算干净的羊毛重量（CFW）。对个体中侧羊毛样本进行平均纤维直径（AFD）、纤维直径标准差（SD-FD）和中等纤维百分比（%M）、马海毛百分比（%K）和总髓质纤维百分比（%T）的量化。品种类型之间 1 岁 CFW 没有差异（P≥0.96）。4 岁雷蒙达母羊的 CFW 比 4 岁波尔派（1.83 公斤）和 RW-RA 母羊（1.86 公斤）重（2.29 公斤；P<0.001），两者之间没有差异（P>0.99）。在 1 岁和 4 岁时，品种类型之间的 AFD 存在差异（P<0.001），雷蒙达的 AFD 最细（分别为 20.1 和 21.9 µm），RW-RA 为中等（分别为 22.8 和 24.8 µm），波尔派最粗（分别为 24.2 和 26.7 µm）。同样在 1 岁和 4 岁时，SD-FD 在雷蒙达最低，在波尔派中间，在 RW-RA 最大（P<0.01）。RW-RA 母羊的羊毛中 %M、%K 和 %T 较高（P<0.001），而雷蒙达和波尔派母羊的羊毛中 %M、%K 和 %T 没有差异（P>0.99）。结果表明，与波尔派和 RW-RA 较粗糙、变化较大的羊毛相比，雷蒙达的羊毛产量更高。尽管过去的研究报告称波尔派和 RW-RA 母羊的羔羊产量更高，但在最近的市场条件下，这些品种的年总收入将高于雷蒙达。
