Treatment of gilts with leukocytes from the sire does not improve reproductive performance

The effectiveness of pretreatment of gilts with leukocyte antigens on reproductive performance was studied. Two experiments were carried out that involved the treatment of gilts with leukocytes prior to artificial or natural insemination. Gilts were randomly assigned to one of three treatment groups. Group A gilts received two doses of 2 x 10(8) sire's leukocytes; one injected intra-peritoneal at first estrus and the other infused into the uterus immediately prior to insemination at the second estrus cycle. Group B gilts were similarly treated with the 'gilt's own' (autologous) leukocytes and Group C animals received phosphate buffered saline as controls. The same boars were used as sires across all three treatment groups. Gilts were slaughtered during the fifth week of pregnancy and their reproductive performance assessed. When data from the three groups were compared there were significant differences in embryo survival and placental weights between the sire's leukocyte treatment and PBS control groups. Embryo survival rate (No viable embryos/No corpora lutea x 100) at the fifth week of gestation was lower (p < 0.05) and placental weights were higher in the sire's leukocyte treatment group (p < 0.05). However, the latter may likely be due to fewer developing embryos. Embryo survival and placental weights did not vary significantly between the sire's and autologous leukocytes treatment groups. The treatment of gilts with leukocytes from the boars used as sires showed no improvement on subsequent reproductive outcome over that observed for the autologous leukocytes or PBS control treatments. Consequently, in a healthy well managed herd leukocytes treatment offers no advantage to pig reproductive function.