The objective of this study was to investigate the effect of uterine presensitization with sperm or seminal antigens on replacement gilt fertility. One hundred and forty one hybrid-gilts at the age of 160-165 days were housed. Oestrus was induced with PMSG and hCG injection at housing. Oestrus detection was done twice daily using a boar. Intrauterine preinfusions were performed 24 hours after the onset of oestrus at the first and second oestrus. Groups of gilts were subjected to 5 different treatments: dead sperm (DS, n = 29), seminal plasma (SP, n = 29), seminal plasma and dead sperm (SP + DS, n = 28), physiological saline solution (SS, n = 28) and control (n = 27). Gilts which always had a positive backpressure test (BPT) at infusion time were analysed separately (Group 1) from those which had at least one negative BPT at infusion time (Group 2). Only one artificial insemination (AI) was performed 24 hours after the onset of the BPT at the third oestrus. Twenty-eight to thirty-two days after AI the gilts were slaughtered, fetuses and corpora lutea counted. In the group 1 the pregnancy rates by SP gilts (100%) was significantly (p<0.05) superior than the control (90%), SP + DS (90.9%) and SS (80%), however was similar to DS (92.9%) infused gilts. In the group 2 there were no differences (p<0.05) among groups. There was no difference among treatments with regard to the ovulation rates, number of normal embryos and embryonic loss rates. These results suggest that any significant improvement caused by uterin presensitization might only be observed when overall herd reproductive indexes are low.
Marrã; Fertility; Uterus
