CROSSBREEDING SWINE: REPRODUCTIVE PERFORMANCE OF SEVEN BREEDS OF SOWS BRED TO PRODUCE CROSSBRED PROGENY

Abstract

Data were obtained from 57 Yorkshire (Y), 44 Landrace (LD), 39 Lacombe (LC), 34 Hampshire (H), 21 Duroc (D), 19 Berkshire (B), and 7 Large Black (LB) gilts farrowing crossbred litters by LD, LC, H, D, B, LB and Tamworth (T) boars in a half polyallel mating design. The traits studied were weight at puberty, number of normal teats, number of services per conception, gestation period, litter size and weight at birth, 21 days and weaning (35 days), average pig weight, mortality rate at birth and during suckling, and change in dam’s weight during nursing. The effect of breed of dam was significant (P < 0.01) on all traits studied except weight at puberty, number of services per conception and mortality rates at birth and during suckling. Gestation period was significantly longer for B, LB and Y than for sows of other breeds. LB sows had the smallest and B the lightest litters, while the largest and heaviest litters at birth, 21 days and weaning were those from LC and Y sows. LC, LD and Y sows had more teats and lost more weight during nursing than other sows. The effect of breed of sire was nonsignificant for all the characters studied. Length of gestation was 0.08 days shorter, weaned litters 0.32 larger and 5.9 kg heavier, and weaned pigs 0.51 kg heavier for sows farrowing their second litter than for gilts. The partial regressions on age of dam at farrowing were not significant except for mortality rate during the suckling period, litter size, litter weight and average pig weight at birth. The crosses with the heaviest litters at weaning were T × LC, T × Y, LB × LD and D × Y, in that order.