Effects of farrowing induction with prostaglandins on farrowing traits and piglet performance: A systematic review and meta-analysis

Induction of farrowing with prostaglandins is a way of increasing farrowing supervision and to provide adequate care for piglets in the first hours of life. However, some studies observed negative effects associated with induction, including decreased piglet viability, reduced birth weight and decreased colostrum yield. Furthermore, the farrowing response of sows to prostaglandins treatment varies among studies, largely influenced by the induction protocol applied. Thus, a systematic review and meta-analysis was carried out to evaluate the effects of farrowing induction with prostaglandins on stillbirth rate, birth weight, pre-weaning mortality, weaning weight, farrowing duration and colostrum and milk characteristics as well as the farrowing response to prostaglandin treatment. The interval from farrowing induction to onset of farrowing (IFIOF) was 31 h, and a twice application of prostaglandin increased by 37% the proportion of sows farrowing during the next working day. Prostaglandins had no effect on farrowing duration (P > 0.05). Piglet birth weight and weaning weight were only decreased (P < 0.05) when farrowing was induced ≥3 days before the expected farrowing date (based on herd average or in gestational length of the control group). Induction three or two days before the expected farrowing date had no effect on stillbirth rate; conversely, stillbirth rate was reduced by 28% (P < 0.05) when induction was performed one day before the expected farrowing date. Farrowing induction had no influence on pre-weaning mortality. The present study strengthened the observations that farrowing induction with prostaglandins is a valuable tool to reduce gestational length variation and to synchronize farrowing during the working day, allowing better assistance to sows and piglets. To obtain the maximum benefit of farrowing induction, it is recommended that induction should be performed one or two days before the expected farrowing date.