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) and winter (n=449). Sows were submitted to five treatments, which consisted of infusions of seminal plasma (SP), dead semen (DS), 17beta-estradiol solution (ES), and physiological solution (PS) and a control group (CG). Sows received three inseminations, the first performed 8-12 hours after heat detection, and the other in the following morning and/or afternoon. In relation to return to oestrus rate and adjusted farrowing rate, there were no differences between treatments (p>0.05). In the analysis of the regression model adopted to determine litter size, an interaction between season and treatment was observed (p<=0.01). In the summer, sows submitted to SP infusion had more 0.89, 1.20, 1.34 and 2.31 piglets than those treated with ES, DS, PS and CG (p<0.05). In the winter, the group receiving PS 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 efficient to increase the number of born piglets specially during the summer. However, complementary studies are needed to explain the effect of this treatment in different seasons and in different farrowing order.
seminal plasma; dead semen; estradiol; farrowing rate; litter size
