Effects of altrenogest on reproductive performance of gilts and sows: A meta-analysis.

Altrenogest is a synthetic progestogen that allows for synchronization of the time of estrus in swine. Its effect on reproductive performance, however, is inconsistent due to conflicting data in the scientific literature. A meta-analysis of published data, therefore, was performed to determine whether altrenogest affects gilt and sow reproductive performance. Altrenogest administration to pigs enhanced the number of piglets born alive per litter (NBA), total number born per litter (TNB), estrous rate within 10 days after treatment (ER) and pregnancy rate (PR) as well as the farrowing rate (FR) of gilts. The NBA and TNB of primiparous sows fed altrenogest were improved although FR was less. In multiparous sows, altrenogest treatment did not result in any improvement for any of the five analyzed variables. Additionally, 14-day treatment regimens for gilts and >8-days for primiparous sows improved reproductive performance and extent of estrous synchrony. The effects of altrenogest on reproductive performance of swine were parity and treatment duration dependent.