Incidence and prevention of early parturition in sows.

A retrospective study, based on 60,990 farrowing records from 35 commercial herds, was performed to determine the incidence of early parturition (<114 d) and to investigate the relationship between early parturition and total number of piglets born, number of piglets born alive and percentage of stillborn piglets per litter. The mean gestation length was 115.4 ± 1.62 d, and early parturition occurred in 10% of all farrowing records. Sows with early parturition had significantly more stillborn piglets and a larger litter size compared to sows with a normal gestation length (114-117 d). Sows with a gestation length <114 d were 1.2 times (95% CI: 1.19-1.21; p<0.001) more likely to have an early parturition at the subsequent parity. A second study was performed in four herds (n=329) to investigate the efficacy of altrenogest administration on 110-112 d (T112) or 111-113 d (T113) of gestation for preventing early parturition and to investigate the effect of this treatment on the reproductive performance of sows. The interval between the last altrenogest treatment and the onset of parturition was 3.3 ± 1.32 (T112) or 2.0 ± 0.89 (T113) days. The gestation length of sows of the altrenogest group (T112 + T113) (115.3 ± 1.23 d) was significantly longer compared to gestation length of the non-treated sows (114.7 ± 1.69d) (p<0.01). Altrenogest treatment had no negative effect on the reproductive performances of the sows. In conclusion, the administration of altrenogest in late gestation is an effective and safe method to prevent early parturition and can counteract the reproductive losses because of premature farrowing, which may occur in a substantial part of the farrowing events.