Effect of cloprostenol treatment at artificial insemination on sow fertility

In two experiments, we examined the effect of administration of cloprostenol at artificial insemination on fertility of multiparous sows. Lactation length was 21 days and only sows exhibiting estrus by 7 days after weaning were included. Cloprostenol was administered by IM injection (175 microg; n=126) or supplemented in the semen dose (525 microg; n=129). Control sows (n=130) received no hormone. In either experiment, there was no effect of any treatment on subsequent litter sizes. In experiment 1, there was no effect of treatment on farrowing rate, but in experiment 2, farrowing rate was higher (p < 0.05) in sows receiving cloprostenol by injection. Taken together, these results indicate no consistent effect of cloprostenol administration by intramuscular injection or by inclusion in the semen dose on sow fertility and so its routine use is not warranted.