Effect of the timing of OvuGel administration on reproductive performance in gilts synchronized for estrus

The objective of this thesis was to evaluate the effects of the time of OvuGelRTM administration on the timing of estrus and ovulation and fertility results in gilts synchronized for estrus by administering MatrixRTM for 14 d. Insemination must occur near the time of ovulation to achieve high fertility results, however, there is no practical method available to determine when ovulation occurs, and, therefore, sows and gilts are commonly inseminated 2 to 3 times over the course of the estrus period. Two exogenous hormones (MatrixRTM and OvuGelRTM) have been developed to aid in the process of estrus detection and insemination. MatrixRTM (Merck Animal Health, Summit, NJ) is an orally active progestogen that is used to synchronize estrus in gilts and OvuGelRTM (JBS United, Sheridan, IN) is a product that has been shown to synchronize ovulation in sows, allowing for a single fixed-time insemination to be used. A review of the literature relating to the timing of estrus and ovulation and the effects of MatrixRTM and OvuGelRTM administration on fertility results in gilts and sows was carried out. Overall, the findings of the review suggest that the timing of estrus and ovulation are highly variable in gilts and sows and could be dependent on a number of factors. In addition, the findings of the review suggest that gilts administered MatrixRTM had similar fertility results compared to gilts that were not administered Matrix RTM, and sows administered OvuGelRTM had similar fertility results compared to sows that were not administered OvuGel RTM. There has been no published research; however, evaluating the effect of OvuGelRTM administration in gilts on timing of estrus, ovulation, or fertility results. In a typical commercial situation, groups of gilts are in estrus and ovulating at different times, however, Matrix RTM administration would facilitate the use of OvuGelRTM and fixed-time insemination in a group of gilts. Little is known, however, of the effect of MatrixRTM administration in combination with OvuGelRTM administration and fixed-time insemination on either the timing of estrus and ovulation or fertility results in gilts. A study was carried out, therefore, to determine the effect of the time of OvuGelRTM administration on timing of estrus and ovulation and fertility results in gilts synchronized for estrus using Matrix RTM. This study showed that the timing of OvuGelRTM administration had a significant effect on both the timing of estrus and ovulation and on subsequent pregnancy and farrowing rates and litter size. Further research is needed to establish the optimum time for administration of OvuGel RTM in gilts that have been synchronized for estrus.