LAMB GROWTH PERFORMANCE OF ROMNELET, COLUMBIA, SUFFOLK, AND N.C. CHEVIOT BREEDS AND ALL SINGLE AND THREE-BREED CROSSES AMONG THEM

Growth performance is presented of 470–1297 purebred and crossbred lambs from several breeding trials conducted during the years 1964–70. The Suffolk breed significantly surpassed all the other breeds in weaning weight, feedlot gain, and final market weight. Least squares analyses revealed that weaning weight and final market weight were significantly (P < 0.01) affected by year, age of dam, sex, rearing type, breed of dam, and breed of sire. Total feedlot gain was affected significantly (P < 0.01) only by year, sex, breed of dam, and breed of sire. Suffolk breed was superior in maternal ability in purebred as well as in crossbred females on the dam’s or sire’s side. Suffolk sires also improved significantly (P < 0.01) the performance in weaning weight, total feedlot gain, and final market weight. Single cross and three-breed cross lambs represented a 5 and 14.6% superiority in weaning weight over purebreds. In feedlot gain, both the single cross and three-breed cross lambs gained about 7% more than the purebred lambs. In final market weight, the single cross lambs were 7.3% and three-breed cross lambs 11.4% heavier than the purebred lambs.