Reproductive performance of sows submitted to uterine infusions in the beginning of oestrus

This study aimed to evaluate the reproductive performance of sows submitted to uterine infusion with different products at the beginning of oestrus. A total number of 1.019 females were controlled during the summer (n=570) an d winter (n=449). Sows were submitted to five treatments, which consisted o f infusions of seminal plasma (SP), dead semen (DS), 17 beta-estradiol solu tion (ES), and physiological solution (PS) and a control group (CG). Sows r eceived three inseminations, the first performed 8-12 hours after heat dete ction, and the other in the following morning and/or afternoon. In relation to return to oestrus rate and adjusted farrowing rate, there were no diffe rences between treatments (p>0.05). In the analysis of the regression model adopted to determine litter size, an interaction between season and treatm ent was observed (p less than or equal to 0.01). In the summer, sows submit ted to SP infusion had more 0.89, 1.20, 1.34 and 2.31 piglets than those tr eated with ES, DS, PS and CG (p<0.05). In the winter, the group receiving P S increased litter size in 1.25 and 0.91 piglets compared to DS and CG (p<0 .05). This study showed that uterine infusion of seminal plasma is efficien t to increase the number of born piglets specially during the summer. Howev er, complementary studies are needed to explain the effect of this treatmen t in different seasons and in different farrowing order.