Abstract:

Effect of gonadotropin at weaning on reproductive performance of primiparous sows

Roy N. Kirkwood DVM, PhD; Frank X. Aherne PhD; George R. Foxcroft PhD

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Objective: To determine the effect of administering gonadotropin (Gn) at weaning on the fertility of primiparous sows.

Methods: At weaning, primiparous sows did (n=609), or did not (n=641), receive an injection of 400 IU PMSG plus 200 IU hCG. Sows were bred at their first postweaning estrus. Subsequent farrowing rate and littersize were recorded.

Results: The injection of Gn resulted in a shorter and more synchronousweaning-to-estrus interval (P<.0001) and a greater proportionof sows bred by 7 days after weaning (P<.0001). There was no effecton farrowing rate, but subsequent litter size was reduced (P<.02).However, the number of pigs produced per sow weaned was higher in Gn-treatedsows.

Implications: Administering Gn proved to be an effective toolfor facilitating the achievement of breeding targets. Although litters maybe smaller, this would be offset by increased pig production per sow weaned.

Keywords: sows, weaning, gonadotropin

Cite as: Kirkwood RN, Aherne FX, Foxcroft GR. Effect of gonadotropin at weaning on reproductive performance of primiparous sows. J Swine Health Prod 1998;6(2):51-56.

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