Production efficiency of crossbred ewes and that of their daughters and granddaughters.
Ewes of eight crossbred groups, born in 1973 and 1974, were maintained under two pasture management systems for five and four production years, respectively. After that experiment terminated, those crossbred ewes produced Polypay-sired lambs in 1979 and were then sold. Ewe lambs from those three-bred crosses were backcrossed to Polypay rams to produce lambs from 1980 to 1983. Five ancestor-descendant data sets (three involving dams and daughters and two involving granddams and granddaughters) were examined to study relationships between production efficiency of ancestor ewes and similar traits measured on their descendants. Ancestor cumulative prolificacy was positively but not significantly associated with cumulative prolificacy in the descendants. Regressions of descendant net revenue on ancestor net revenue were predominantly negative but generally were not significant. There was a tendency for prolific ancestors to produce costly but less profitable descendants. These results may be due to economic conditions (high feed costs and low lamb values) that persisted during the course of the experiment.
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Oregon State University, Corvallis 97331.
Hohenboken
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D000822:Animal Husbandry / Q000191:economics; D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D012756:Sheep / Q000235:genetics*