Effect of split-weaning interval on return to estrus and sow fertility
Casimiro Tarocco, DVM; Fabio De Rensis, DVM, PhD; Roy N. Kirkwood, DVM, PhD; Rong-Cai Yang, PhD
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Objective: To determine the effect on timing of return to estrus and subsequent fertility of primiparous and multiparous sows when litter size suckled is reduced to five piglets (split weaning) 5, 6, or 7 days before full weaning.
Methods: Primiparous (n=181) and multiparous (n=759) sows of Large White and Landrace breeding on a commercial swine farm were assigned at the time of parturition to be either split weaned (n=628) or to serve as controls (n=312). Sows were split weaned by removing the heaviest piglets at 21 days of lactation, leaving five to seven piglets with the sow until full weaning 5, 6, or 7 days later. Control litters were weaned at 22+/-4 days of lactation. Sows were bred at the first observed estrus after full weaning.
Results: The mean wean-to-estrus interval (WEI) was longer (P<.01) for primiparous than multiparous sows. The WEI was shorter (P.05) for sows split weaned 6 or 7 days before full weaning than for control sows, but was not different for sows split weaned 5 days before full weaning. In both parity groups, split-weaned sows tended to return to estrus 1 day earlier than control sows. The percentage of sows bred by day 5 after weaning was greater when sows were split weaned 6 or 7 days before full weaning (P<.06 for primiparous and P<.02 for multiparous sows) than for control sows, but was not different for sows split weaned 5 days before full weaning. Farrowing rate to first service and subsequent total born litter size were not affected by treatment.
Implications: On this farm, with the lactation length employed, split weaning of litters for up to 7 days before full weaning slightly advanced the onset of the post-weaning estrus. For other farms, it is possible that where a high proportion of sows are bred 6 days or more after weaning (presumptive infertile period), the practice of split-weaning may increase the proportion of sows bred by 5 days after weaning, and so potentially increase herd fertility. However, the efficacy of split weaning should be evaluated for individual farms.
Keywords: split weaning, fertility
Cite as: Tarocco C, De Rensis F, Kirkwood RN, et al. Effect of split-weaning interval on return to estrus and sow fertility. J Swine Health Prod 2000;8(5):221-223.
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