Production of yearling Targhee or Finn-Dorset-Targhee ewes managed as a farm or range flock.

Production data from 681 yearling ewes were evaluated for the effect of ewe breed and management system on fertility, prolificacy, lamb birth weight, lamb survival, lamb weaning weight, ewe fleece weight, and total lamb weight weaned per ewe exposed. Two hundred seven straightbred Targhee (T) and 474 1/4 Finn-1/4 Dorset-1/2 Targhee (FDT) crossbred ewes managed in a range or farm flock system were included in this study. Ewes were born in 1984 through 1987 and lambed the first time as 2-yr-olds. The basic model included main effects of ewe breed and management system. Lamb sex was added to the model for birth and weaning weight analysis. The FDT ewes had higher (P < .05) fertility (95.3 vs 91.3%) and (P < .01) prolificacy (1.93 vs 1.45 lambs) than the T ewes. Targhee ewes had heavier (P < .01) lambs at birth (5.2 vs 4.0 kg) and weaning (26.1 vs 23.4 kg, P < .01) and produced more (P < .01) wool (3.8 vs 3.2 kg). Lamb survival was not different (P > .10) between the breeds or management systems. Although FDT lambs were lighter at weaning, FDT ewes weaned 5.8 kg more (P < .01) total lamb weight per ewe exposed than did the T ewes (34.7 vs 28.9 kg), because FDT weaned more (P < .01) lambs per ewe exposed (1.46 vs 1.09 lambs). Farm flock ewes were more prolific (1.73 vs 1.64 lambs, P < .05) and had heavier lamb birth weight (4.8 vs 4.4 kg, P < .01) than range flock ewes.(ABSTRACT TRUNCATED AT 250 WORDS)