Productivity of purebred and crossbred finnsheep. II. Lamb weights and production indices of ewes.

Birth and weaning weights were studied for purebred Finnsheep, Suffolk, Targhee and Minnesota 100; F1 Finnsheep crosses; F2: and standard breed and Finnsheep backcrosses. Finnsheep lambs were the smallest of all lambs at birth, but ranked second among purebreds in 70-day weaning weight (Suffolks, 21.0 kg vs Finnsheep, 17.6 kg). Ewe body weight, grease fleece production and total adjusted weight of weaned lamb were compared among purebreds and crossbreds. The Finnsheep was the smallest pure breed, yielded the lightest fleeces, but produced the heaviest total weight of weaned lamb. The F1 ewes were all heavier and produced more wool than the midparent mean of their respective breeds. They also produced markedly more weaned lamb than did the parental standard breeds. Body weight, wool and lamb production were all lower in the F2 than in the F1 groups. Ewe index was calculated as the total adjusted (male, 70-day equivalent) weight of weaned lamb plus three times the grease fleece weight. The ranking of purebreds was Finnsheep, Targhee, Suffolk and Minnesota 100. Average ewe index values for F1 ewes were greater than those for respective parental and standard breeds. F2 and standard breed backcross ewes had lower index values than did F1 or Finnsheep backcross ewes. Ewe index per unit of ewe body weight was also evaluated. Finnsheep ranked highest, followed by the 3/4 Finnsheep. The Targhee was the best of the standard breeds for this index.