Ad libitum lactation feeding of sows introduced immediately before, at, or after farrowing

The timing for introducing ad libitum lactation feeding around farrowing was studied in an experiment comprising 20 blocks of three littermate sows and a total of 1085 piglets in 90 farrowings. Sows were given 2.2 kg daily of a diet containing 12.1 MJ metabolizable energy and 120 g digestible crude protein per kg from service until ad libitum feeding was introduced either 4 days before expected farrowing (treatment BEF), the farrowing day (AT), or 3 days after farrowing (AFT). BEF and AT sows had a higher fetal daily food consumption during the experimental period, 5 days before farrowing to weaning at 35 (+/-3) days, than AFT sows (7.2, 7.2 and 6.6 kg, respectively). BEF and AT sows tended to have deeper ultrasonic backfat (BF) than AFT sows. The mobilization of body reserves during lactation was modest as reflected in negligible losses of live weight (LW) and BF, low serum concentrations of non-esterified fatty acids and creatinine, together with increasing serum urea concentrations as well as the high proportion of sows served within 8 days after weaning (over 90% of the primiparous sows). Sow rectal temperature increased on the farrowing day but was also influenced by feeding level. No cases of agalactia post partum were diagnosed. Litter size, piglet LW, piglet mortality and creep food consumption did Mot differ between treatments, although there was a tendency for lower LW and increased mortality, particularly of piglets crushed by the sow, in litters of AFT sows. It can be concluded that there was no advantage in delaying the introduction of ad libitum feeding until after farrowing.