Effects of within-litter birth weight variation of piglets on performance at 3 weeks of age and at weaning in a Large White×Landrace sow herd

The effect of piglet birth weight variation on subsequent weight variations and litter performance in Large White×Landrace sows is not well understood. The objective of the current study was to determine the relationship between within-litter birth weight coefficient of variation (CVB) and performance of piglets at 3 weeks and at weaning. A total of 1836 litter records, collected between January 1998 and September 2010 at the Agricultural Research Council (ARC), Irene, were used. The CVB had a linear relationship with survival at 3 weeks (SURV3) (b=−0.20; P<0.05) and within-litter weight coefficient of variation at 3 weeks (CV3) (b=0.50; P<0.05). Litters with high CVB had more deaths at 3 weeks (P<0.05). Increase of CV3 with CVB varied with parity (P<0.05). The rate of increase of CV3 with CVB was highest in Parity 1 (b=0.41) followed by Parity 2 (b=0.36) then middle aged (Parity 3-5) sows (b=0.32). There was no significant relationship between CVB and litter weight at 3 weeks (LWt3) or mean litter weight at 3 weeks (MWt3) (P>0.05). Weight variation at weaning was positively skewed (skewness value of 0.81). The survival to 3 weeks (SURV3) ranged from 13.3% to 100% with a mean of 87.6%. The CVB had a linear relationship with both within-litter weaning weight coefficient of variation (CVW) (b=0.50; P<0.05) and percent survival to weaning (SURVW) (b=-0.04; P<0.05). There was an unfavorable positive relationship between CVB with both CVW and SURVW. It can be concluded that litter performance at weaning is related to CVB.