Wilson Carrie S, Taylor J Bret, Notter David R, Murphy Thomas W, Stewart Whitney C, Lewis Ronald M
USDA, ARS, Range Sheep Production Efficiency Research Unit, U.S. Sheep Experiment Station, Dubois, ID.
School of Animal Sciences, Virginia Tech, Blacksburg, VA.
Transl Anim Sci. 2024 Dec 17;8:txae176. doi: 10.1093/tas/txae176. eCollection 2024.
The Targhee breed is important to range sheep production in the Western United States. The objective of this research was to integrate industry sires participating in national genetic evaluation through the National Sheep Improvement Program (NSIP) into the U.S. Sheep Experiment Station (USSES) flock, where the breed originated, to benchmark sire performance. Estimated breeding values (EBV) of industry sires ( = 16) and USSES sires ( = 12) from the 2023 NSIP Targhee genetic evaluation differed ( < 0.05) only for the NSIP Number Born EBV. This difference, and small (nonsignificant) differences favoring industry sires for maternal weaning weight, yearling fiber diameter, and yearling staple length EBV also resulted in greater ( < 0.05) Western Range Index scores for industry sires. The performance of sires' direct progeny born 2016 to 2018 was compared for 17 traits. After data cleaning, there were 664 progeny (417 from industry sires and 247 from USSES sires) with 146 to 664 records per trait. Least squares means differed ( < 0.05) for grease fleece weight, side fiber diameter, and britch fiber diameter in favor of the industry sires. Production traits were measured from the progeny and other retained descendants of both sire genetic groups from 2016 through 2022. After data cleaning, there was a range of 1,138 to 1,493 records per trait. A three-generation pedigree was constructed and the proportional assignment of each lamb to each genetic group (e.g., 0.5 industry, 0.5 USSES) was included in an augmented relationship matrix. A univariate animal model was fitted for each lamb trait and a repeated measures model for each of the three ewe traits was fitted to estimate variance components and predict breeding values. Genetic group solutions did not differ ( > 0.05) for any of these traits but provided a means by which to compare the two groups. Establishment of a Targhee genetic reference flock at USSES has been initiated, which can be used to address issues of importance to the industry.
塔尔吉羊品种对美国西部的草原养羊业很重要。本研究的目的是将通过国家绵羊改良计划（NSIP）参与全国遗传评估的行业种公羊纳入该品种发源地的美国绵羊实验站（USSES）羊群，以评估种公羊的性能。2023年NSIP塔尔吉羊遗传评估中，行业种公羊（(n = 16)）和USSES种公羊（(n = 12)）的估计育种值（EBV）仅在NSIP出生数量EBV上存在差异（(P < 0.05)）。这种差异，以及在母羊断奶体重、周岁纤维直径和周岁毛长EBV方面有利于行业种公羊的微小（不显著）差异，也导致行业种公羊的西部草原指数得分更高（(P < 0.05)）。比较了2016年至2018年出生的种公羊直接后代的17个性状表现。数据清理后，有664个后代（417个来自行业种公羊，247个来自USSES种公羊），每个性状有146至664条记录。在含脂羊毛重量、体侧纤维直径和腿部纤维直径方面，最小二乘均值存在差异（(P < 0.05)），有利于行业种公羊。对2016年至2022年两个种公羊遗传组的后代及其他留种后代进行了生产性状测定。数据清理后，每个性状有1138至1493条记录。构建了三代系谱，并将每只羔羊在每个遗传组中的比例分配（如0.5行业、0.5 USSES）纳入增广亲缘关系矩阵。对每个羔羊性状拟合单变量动物模型，对三个母羊性状分别拟合重复测量模型，以估计方差组分并预测育种值。这些性状的遗传组解在任何情况下均无差异（(P > 0.05)），但提供了一种比较两组的方法。USSES已启动建立塔尔吉羊遗传参考群，可用于解决该行业的重要问题。
