EFFECT OF WEANING REGIMES ON GROWTH PERFORMANCE, STRESS AND BEHAVIOURAL RESPONSES IN WEANLING PIGS

Abstract

Weaning is one of the most stressful events in pigs as this affects their health, growth performance and welfare especially during the first week post-weaning. Early weaning exposes weanling pigs to severe weaning stress. Therefore, this study assessed the effects of different weaning regimes on weanling pigs' growth, stress and behavioural responses. Seventy-two weanling pigs, allotted to three treatments in 6 replicates in a completely randomised design, were used for this study. The weanling pigs were weaned at four weeks (T1), six weeks (T2) and eight weeks (T3) and involved in the study immediately after weaning. Growth performance (feed intake, weight gain and feed conversion ratio − FCR), stress indices (corticosterone, white blood cell − WBC) and behavioural indices (feeding and aggressive behaviour) were measured for 6 weeks, twelve days and ten days post-weaning, respectively. Data were analysed using descriptive statistics and ANOVA at α 0.05. Feed conversion ratio of weanling pigs in T1 (2.42 ± 0.09) was significantly higher (p < 0.05) than in T2 (2.23 ± 0.15) and T3 (2.22 ± 0.10) groups. Corticosterone concentration in the weanling pigs ranged from 55.83 ng/ml (T1) to 48.31 ng/ml (T3) on day 3, from 45.58 ng/ml (T2) to 45.42 ng/ml (T1 and T3) on day 9, and from 46.52 ng/ml (T1) to 45.25 ng/ml (T2) on day 12. The white blood cell (WBC) count in the weanling pigs in T1 (8.83 ± 0.07 × 103 µl) was significantly higher (p < 0.05) than in T2 (8.53 ± 0.12 × 103 µl) and in T3 (8.62 ± 0.14 × 103 µl) on day 0. The values obtained for days 6, 9 and 12 demonstrated the same trend. Feeding behaviour showed that weanling pigs in T1 spent lesser time feeding than in T2 and T3 groups. The values ranged from 41.72 % (T1) to 70.31 % (T3). Weanling pigs in the T1 group showed more aggression towards pen mates for the first 3 days compared to T2 and T3 groups. The values ranged from 0.52 % (T3) to 9.24 % (T1). In conclusion, this study revealed that different weaning regimes have varying effects on the performance and welfare of pigs. It is important to carefully consider the weaning regimes implemented in pig production to minimize stress and promote healthy growth.