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Lifetime Production of 1/4 and 1/2 Finnsheep Ewes from Rambouillet, Targhee and Columbia Dams as Affected by Natural Attrition

U.S. Department of Agriculture^,2, Dubois, ID 83423

Abstract

Lifetime production of first-generation 1/4 and 1/2 Finnsheep crossbred ewes from Kambouillet (R), Targhee (T) and Columbia (C) dams was compared with that from randomly selected purebred R, T and C ewes. All 1,190 ewes, representing nine breed groups, were managed under range conditions and mated annually to Suffolk rams. Lifetime production was evaluated as the total lamb and total wool production per ewe from the time each entered the breeding flock at 7 mo of age through the period each remained in the flock (potentially seven producing years). Culling was for debilitating unsoundness only. The study was designed to determine the average lifetime production per breed group as affected by natural ewe attrition. Orphan-reared lambs were not included in lamb production nor were foster lambs, except those actually born in and reared by the groups. Differences among pooled breed groups (1/4 Finns, 1/2 Finns and purebreds) were not significant for average final age in the flock (5.1, 5.1 and 4.9 yr, respectively), but differences were significant (P < .01) for lifetime lamb and wool production. Average lifetime fleece weights of 1/4 and 1/2 Finn ewes were only 95 and 82% as high, respectively, as those of purebreds. However, 1/4 and 1/2 Finn ewes had 34 and 46%, respectively, higher numbers of lambs weaned (at 130 d) and 30 and 38% higher total weight of lamb weaned than purebreds. Considering the unit value of wool to be 2.5 times the unit live-weight value of lamb, and after adjusting for differences in value of wool grades, the net value of lifetime production from Finn crosses was about 15 and 17% higher, respectively, than that of purebreds.

¹ The authors gratefully acknowledge the valuable technical assistance of T. R. Kellom in collecting and assembling the data.

² ARS, U.S. Sheep Exp. Sta., Dubois, in cooperation with the Univ. of Idaho, Moscow 83843.