PERFORMANCE OF PROGENY OF FINNISH LANDRACE AND DORSET HORN RAMS MATED TO EWES OF VARIOUS BREEDS AND CROSSES

Abstract

Over a 3-yr period, 1,556 lambs were produced from matings of Dorset Horn and Finnish Landrace rams to ewes of the Romnelet, Columbia, Suffolk, and North Country Cheviot breeds and their 2-, 3-, and 4-breed crosses. Also, 142 purebred lambs of the four dam breeds were produced as a basis for contemporary comparisons. The average weaning weight of the purebred lambs was 23.7 ± 0.4 kg; of the 2-breed cross lambs, ½-Dorset lambs averaged 25.1 ± 0.5 kg and ½-Finnish Landrace 25.6 ± 0.5 kg. The 3-breed cross ½-Dorset lambs averaged 27.1 ± 0.4 kg and ½-Finnish Landrace lambs 26.1 ± 0.4 kg; and 4-breed cross ½-Dorset lambs 27.1 ± 0.4 kg and ½-Finnish Landrace lambs 26.8 ± 0.4 kg. The 5-breed cross ½-Dorset and ½-Finnish Landrace lambs both averaged about 27.5 ± 0.5 kg. Weight-per-day-of-age to market weight showed the same trend as weaning weight among the purebred and crossbred lambs. Purebred lambs were exceeded by 2-breed cross lambs in weaning weight (7%) and weight-per-day-of-age to market weight (6%) and by 3-breed cross lambs (13% and 8%, respectively). No practical additional improvement for either trait was evident in 4-breed and 5-breed crosses. Two-breed cross ewes (Romnelet × Suffolk and Columbia × Suffolk) raised lambs of about the same weaning weight (27.7 and 27.3 kg) as the 3-breed and 4-breed cross ewes (24.9–27.4 kg). Dorset Horn and Finnish Landrace rams contributed about equally to weaning weights (26.6 and 26.5 kg) and weight-per-day-of-age to market weight (0.241 and 0.236 kg). The average score of the ½-Finnish Landrace carcasses was slightly, but significantly, better than that of the ½-Dorset Horn carcasses. Both Dorset Horn and Finnish Landrace rams produced crossbred lambs with satisfactory growth and carcass merit.