Effect of boar’s breed on piglets’ vitality and growth performance from birth to weaning.

A trial was carried out to compare gestation length (without farrowing induction), farrowing and lactation progress when sows were artificially inseminated with semen from either Yorkshire×Pietrain crossbred sires (treatment LW×PP) or purebred Pietrain (treatment PP) homozygote halothane reacting sires. Within each of the four batches studied, sows were allocated to one of both types of sires, depending on their parity and body condition. Gestation length averaged 114.3 days and farrowing lasted 5.0 hours on average, whichever the sire concerned. Stillbirth rate was not different among type of boar (7 and 9% in treatments LW×PP and PP, respectively). Losses over the first 24 hours of life were higher in piglets from PP sire (8 vs. 5% in LW×PP) but the difference was not high enough to induce a significant difference on litter size at weaning (10.9 piglets). Growth rate averaged 270 g/d/piglet for both treatments. Proportion of splayleg piglets was not higher with PP sire but these animals seemed to be more sensitive to infectious lameness. Estimation for genetic sensitivity to these pathologies needs to be more specifically studied.