Increasing the predictability of cloprostenol-induced farrowing in sows

Objective: To determine the effect of a second injection of either cloprostenol or oxytocin after initial cloprostenol induction on the farrowing response of sows. Methods: Two experiments were conducted. In experiment 1, sows received one of two treatments: either a single IM injection of 175 mu g cloprostenol at day 113 of gestation (n = 49) or an IM injection of 175 mu g cloprostenol at day 113 of gestation followed by second IM injection of 175 mu g cloprostenol 6 hours later (n = 54). In experiment 2, sows received either a single (n = 59) or a double (n = 48) cloprostenol injection, as above, or a third treatment in which an IM injection of 30 IU oxytocin (n = 56) replaced the second cloprostenol injection. Results: After a single cloprostenol injection, 61 % of sows farrowed during the following working day. When a second cloprostenol or oxytocin injection was administered 6 hours later, 86 % of sows farrowed during the next working day. Implications: A regime of cloprostenol administered twice or cloprostenol plus oxytocin markedly improved the predictability of induced parturition. This level of predictability should encourage more producers to employ induction technology.