Impact of an extended photoperiod in farrowing houses on the performance and behaviour of sows and their litters

The effects of an extended photoperiod around parturition and throughout lactation on performances of primiparous sows and their piglets were studied. Sows were assigned to two light regimens: (1) standard (CTL, n = 28), 8 h of daily light from day 112 of gestation until day 23 of lactation; and (2) extended (TRT, n = 26), 23 h of daily light from day 112 of gestation to day 4 of lactation and 16 h thereafter. Colostrum intake was estimated based on a 24-h piglet weight gain starting at the end of farrowing. Piglets were weighed on days 4, 7, 14, 21 (weaning on day 23), 35 and 56. On days 4 and 21 of lactation, milk and blood samples were obtained. Behaviour was recorded on days 3 and 20. Piglet feed intakes were noted post-weaning until day 56. The TRT sows had lower concentrations of melatonin than the CTL sows on day 4 (P   0.1). Litter growth during lactation was unaffected (P > 0.1)...