Impact of a ten-week lactation period on sow and litter performance in organic outdoor production

Abstract

In recent years the average lactation period for organic pigs reared outdoors has been extended to improve piglet robustness at weaning and to eliminate the need for a separate weaner facility. This study aimed to investigate the performance of outdoor sows and litters after lactation periods of seven and 10 weeks. Twenty litters comprising a total of 251 pigs were assigned to one of two weaning strategies: weaning at seven weeks or weaning at 10 weeks. Post-weaning, the piglets were transferred to outdoor weaner paddocks and monitored until they reached 17 weeks of age. Sows' body weight (BW), back fat thickness (BF), udder, and teat condition were assessed after seven and 10 weeks of lactation. Piglets were weighed at the end of week 7, 10, 14, and 17 post-partum. Sow feed intake was recorded from weeks 8 to 10, while piglets' feed intake was monitored from weeks 8 to 10, 11 to 14, and 15 to 17. There were no changes in sow BF, teat, and udder condition during the three-week extended lactation period (P > 0.05). Sows exhibited an increase in BW by 8.8 kg during the three-week extended lactation period (P < 0.01). The weaning strategy did not affect piglets' average daily gain (ADG), feed intake (ADFI), or feed conversion ratio (FCR), in terms of kg feed per kg gain, from week 10 to 14, as well as ADG and ADFI from week 15 to 17 (P > 0.05). Overall, pigs per litter after 17 weeks and total gain (sow and pigs) from week 8 to 17 did not differ between weaning strategies (P > 0.05). When including feed use for sows, piglets, and weaners, overall FCR in terms of kg feed per kg gain was numerically higher for litters weaned after 10 weeks of lactation (P = 0.11). However, overall FCR in terms of kg crude protein (CP) and metabolizable energy (ME) per kg gain did not differ between weaning strategies (P > 0.05). In conclusion, extended lactation had no detrimental effects on outdoor sows’ body condition and udder condition at weaning. On the other hand, when the piglets are weaned in outdoor conditions, in small group sizes and sorted according to size, weaning at seven or 10 weeks of age seems to be equally suitable strategies to obtain good pig health and high growth rates until 17 weeks of age.