THE INFLUENCE OF ALTERED WEANING MANAGEMENT ON PIGLET GROWTH AND SOW REPRODUCTIVE PERFORMANCE

Abstract

An experiment was undertaken to investigate the influence of split-weaning of litters 7 d before full weaning on the growth of piglets and the reproductive performance of sows. The litters of 27 Yorkshire × Landrace sows were assigned to be either split-weaned (heaviest piglets removed at 21 d of lactation; n = 13) or to act as controls (all piglets weaned at 28 d of lactation; n = 14). The influence on sow and litter performance was monitored. During lactation, mean sow feed intakes in the split-weaned and control groups were 6.9 ± 0.1 and 6.7 ± 0.2 kg d−1, respectively. The diet was formulated to provide 12.3 MJ DE kg−1 and 15.7% crude protein. Nursing piglets were allowed free access to a 20% crude protein creep feed from 7 d of age. Weaned piglets were fed ad libitum a commercial starter diet containing 18% crude protein. Split-weaning had no effect on either the weaning to estrus interval or subsequent litter size (4.5 ± 0.1 vs. 4.3 ± 0.4 d and 12.7 ± 0.9 vs. 13.0 ± 0.9 pigs, for split-weaned and control sows, respectively). However, while control sows lost weight between 21 and 28 d of lactation, the split-weaned sows gained weight (P < 0.02). There was no treatment effect on body weights of nursing piglets but weaning of the heavy piglets at 21 d resulted in a lower (P < 0.05) body weight at 28 d. On days 21 and 28, four sows from each group were blood sampled via indwelling vena caval cannulae at hourly intervals for 10 h. Also, samples were taken every 15 min for 4 h on these days. No treatment effect was noted for mean serum concentrations of luteinizing hormone (LH) or follicle stimulating hormone (FSH). Similarly, there was no effect on LH pulse frequency or amplitude. It is concluded that, in the absence of excessive sow weight loss or prolonged weaning to estrus intervals, the introduction of a split-weaning regime will not enhance sow or litter performance. Key words: Split-weaning, piglet growth, sow performance