The effect of cross-suckling and presence of additional piglets on sucking behaviour and performance of individually housed litters

Abstract

AbstractGrouping of sows and piglets during lactation can cause performance problems associated with disruption of suckling. Cross-suckling and an increase in the number of piglets at the udder during milk let-down have been observed. To investigate the role of these factors, 24 sows and litters were used to study their independent effect on sucking behaviour and performance. Control sows (C) remained in farrowing pens with crates until weaning at 28 days. In treatment 1 (Tl) on day 14 after farrowing, five piglets were removed from the resident (Rl) litter and replaced by five piglets (cross-suckers; CS1) of the same age from a different litter. In treatment 2 (T2) on day 14, five additional piglets (CS2) from other litters were added to the 10 resident (R2) piglets for a period of 24 h. Behaviours of the sows and piglets were video recorded prior to mixing and for 3 days after mixing. Litter weight gain of 11 was significantly reduced in the week after mixing (2–06,1·61 and 2·00 (s.e.d. 0·18) kg/day, P < 0·05 for C, Tl, T2, respectively). Within Tl the growth rates ofRl and CS1 piglets were not significantly different. In the 24 h after mixing, C, Rl, CS1 and R2 piglets gained weight whilst CS2 lost weight (247,186,182,151 and -116 (s.e.d. 44·2) glday, P < 0·01). On the day of mixing, the proportion of suckling attempts which resulted in milk letdown was reduced in treatment groups (0·93, 0·75 and 0·70 (s.e.d. 0·04), P < 0·02 for C, Tl, T2 respectively) and the proportion ofT2 piglets lying near the sow's udder between milk let-down was higher than on C and Tl (0·15, 017 and 0·29 (s.e.d. 0·06), P < 0·05). There was no significant difference in piglet behaviour from 2 days after mixing. Both cross-suckling and introduction of additional piglets transiently disrupted sucking behaviour and adversely affected the performance of the piglets. Increased competition had a much greater effect than unfamiliarity with the environment, with added cross-sucking piglets being greatly disadvantaged relative to substituted cross-sucking piglets.