Effects of Cross-fostering on Piglet Performance at Weaning and Subsequent Reproductive Performance in Hyper-prolific Sows on a Japanese Commercial Farm

Abstract

In recent decades, the prolificacy potential of sows was dramatically developed by genetic im-provements, and cross-fostering (CF) practices are implemented to sows farrowed piglets more than their functional teat number. The objective of this study was to investigate the effect of CF on subsequent performance at weaning and post weaning. The present study was conducted on a commercial farm reared hyper-prolific sows. Data used in this study was 2,292 farrowing records in 1,337 sows that farrowed from March 2016 to February 2017. Sows were classified to three groups based on CF practices: non-CF sows, CF－ sows that defined as sows provided their piglets to other sows, and CF＋ sows that defined as sows received piglets from other sows. Linear mixed-effect model was used to analyze the relationship between CF and productivity, including parity and number of piglets at beginning of lactation in the model. Of 2,292 records, 1,366 were practiced CF (59.6%), and proportion of CF－ and CF＋ sows were 28.5% and 31.1%, respectively. CF was associated with number of piglets weaned and preweaning piglet mortality only in the number of piglets at beginning of lactation 13-14 pigs group: CF－ and non-CF sows had 1.2-1.7% higher preweaning piglet mortality and 0.3-0.4 lower number of piglets weaned (P＜0.05). CF－ sows had 0.2 kg lower piglet weight at weaning than non-CF and CF＋ sows (P＜0.05). CF was not associated with weaning to first mating interval and farrowing rate at first service, but CF－ sows had the highest number of piglets born alive at subsequent parity and CF＋ sows had the lowest (P＜0.05). In conclusion, there was no apparent reduction of productivity between non-CF sows and CF practices sows.