Lamb survival traits in Coopworth sheep selected for high or low backfat depth

摘要: Consumer preferences for lean healthy meat have driven genetic selection leanness in the terminal sire and dual purpose sheep industries over last 20 years. The Invermay Coopworth fat lines were established 1980 to study effects of live weight adjusted on carcass traits, correlated responses other traits. This paper reports findings two year’s data lamb survival performance lines. Records collected from 817 lambs comprising 325, 337 155 fat, lean, a randombred control line, respectively. Neo-natal mortality was not significantly different between three lines, with approximate ly 93% born surviving until tagging. Lamb tagging weaning differed (P<0.05), line animals having 10.9% better than (95.5 verses 84.6%), after adjusting differences year, birth weight, rank, skin thickness, wool length, age dam, mothering ability ewe udder volume. Fat 0.9 ± 0.1kg (mean SEM) lighter animals, intermediate. Udder volume (as measured by water displacement) did differ Mothering distance new during handling field) had thicker skins at same (P<0.01), but no difference length. cannot be fully explained indicating some physiological affecting survival.