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 < 0.05), but prolactin concentrations, milk composition and colostrum intake by piglets were unaffected by treatment (P > 0.1). Litter growth during lactation was unaffected (P > 0.1), but TRT piglets consumed less feed between 23 and 34 d of age (P < 0.05) and weighed less on day 35 (P < 0.05). The TRT piglets were more active than CTL piglets on day 3 of lactation only (P < 0.05). Increasing the period of daily light in the farrowing house did not improve the performance of primiparous sows and their piglets.