Improvement of reproductive efficiency in gilts

English. Studies on the management and breeding/reproduction intervention to improve reproductive efficiency in gilts have been comprehensively reviewed in this professorial lecture. The result of the latest experiments of the author about the similar problem or field of interest have likewise been presented and discussed. Pre breeding intrauterine infusion of killed boar semen could improve the reproductive performance of gilts. The reproductive parameters favorably affected include total litter size at birth (TLSB), litter size born alive (LSBA), litter size at weaning (LSW), litter weight at weaning (LWW). Early occurence of oestrous among gilts could be enhanced through boar exposure. Gilts exposed to boars once or twice daily manifested longer duration of oestrous than those with 0 exposure. The early onset of oestrous among gilt is essential in breeding and management of swine especially in the culling and selectionthus, the presence of boars amon g breeding gilts is an integral components of swine production. Intrauterine intrusion and subsequent breeding of gilts with semen from PSMP boars had altered the sex ratio of piglets but contrary to expectation, the proportion of female piglets was higher than the male. Treatment 2 (single infusion of 100 ml killed boar semen KS1) also yielded results that are contrary to expectation. The proportion of female piglet born to gilts that were infused and subsequently bred with semen from PSFP was lower than the male. The same results were obtained in Treatment 3 [double infusion of 100 ml killed boar semen (KS2)]. Infusion and subsequent breeding of gilts with semen drawn from both PSMP and PSFP boars produced litters that were predominantly males. The outcome of the present work showed significant improvement in the reproductive performance of gilts by intrauterine infusion (KS1 or KS2) of seminal antigens and killed spermatozoa proir to regular breeding. Boar exposure had gr eat influence on the early manifestation of estrus periods. Infusing gilts from boars with PSMP and subsequently using them as breeder aniaml can increase the proportion of female piglets in the succeeding generation. These are inexpensive but effective technologies that could undoubtedly benefit the swine raisers in the country. Therefore, vigorous efforts should be expanded to disseminate this new information to technology users by the government particularly the Department of Agriculture and by the technologist at the local level.

English. CF Lorge C. Bacobo Professorial Chair Lecture College, Laguna (Philippines) 17 Jun 2005