Nawaz M, Meyer H H, Thomas D R
Department of Animal Science, Oregon State University, Corvallis 97331.
J Anim Sci. 1992 Jan;70(1):70-7. doi: 10.2527/1992.70170x.
Six ewe genotypes, generated by mating Coopworth (C), Polypay (P), and Suffolk (S) rams to P and Coopworth-type (Ct) ewes, were exposed to Hampshire rams for spring lambing from 1987 through 1990. Data from 1,013 exposures and 973 resultant lambings were used to analyze reproductive traits and cumulative ewe productivity over 4 yr. Ewe body and fleece weights were also analyzed. Ewes from S sires weaned the heaviest lambs and ewes from P sires weaned the largest number of lambs, resulting in similar total weight of lamb weaned per ewe mated. Coopworth-sired ewes weaned the least total weight of lamb per ewe mated. Ewes weaning twins produced 54% more total litter weight per ewe than those weaning singles. Annual ewe survival averaged 95%, ranging from 93% for S x P and C x P ewes to 97% for P x Ct and C x Ct ewes. When cumulative number and weight of lamb produced was assessed on the basis of all ewes starting the trial, P-sired ewes were highest, followed in order by daughters of S and C sires. Suffolk-sired ewes (67 kg) were 13% heavier than daughters of P rams and 19% heavier than daughters of C rams. Adjustment of lamb production for ewe metabolic body size resulted in C-sired ewes being more efficient than the heavier S-sired ewes. Coopworth-sired ewes produced 32% more wool than ewes sired by the other two breeds. Differences in wool production between ewes weaning one or two lambs were small.(ABSTRACT TRUNCATED AT 250 WORDS)
通过将库泊沃斯（C）、波利佩（P）和萨福克（S）公羊与P型和库泊沃斯型（Ct）母羊交配，产生了6种母羊基因型，并于1987年至1990年让它们与汉普郡公羊交配进行春季产羔。利用1013次配种和973次产羔的数据，分析了4年期间的繁殖性状和母羊累计生产力。还分析了母羊的体重和羊毛重量。S系公羊的母羊所断奶的羔羊最重，P系公羊的母羊所断奶的羔羊数量最多，导致每只配种母羊所断奶羔羊的总重量相似。C系公羊的母羊每只配种母羊所断奶羔羊的总重量最少。断奶双羔的母羊每只所产羔羊总窝重比断奶单羔的母羊多54%。母羊年存活率平均为95%，S×P和C×P母羊为93%，P×Ct和C×Ct母羊为97%。当根据试验开始时的所有母羊评估所产羔羊的累计数量和重量时，P系公羊的母羊最高，其次依次是S系和C系公羊的后代。S系公羊的母羊（67千克）比P系公羊的后代重13%，比C系公羊的后代重19%。根据母羊代谢体重调整羔羊产量后，C系公羊的母羊比体重较重的S系公羊的母羊更高效。C系公羊的母羊比其他两个品种公羊的母羊多产32%的羊毛。断奶一羔或两羔的母羊在羊毛产量上的差异很小。（摘要截短至250字）
