THE EFFECTS OF RECOMBINANT BOVINE INTERFERON-ALPHA ON FERTILITY IN EWES

Recombinant bovine interferon-alpha-I 1 (rBoIFN-alpha) may be useful for enhancing fertility in sheep because it has extensive sequence homology with ovine trophoblast protein-1. To test the effectiveness of rBoIFN-alpha, several experiments were performed in which bred females were given intramuscular injections of rBoIFN-alpha around the time of maintenance of the corpus luteum. Treatment with rBoIFN-alpha enhanced the fertility of ewes that were bred via natural service or embryo transfer of whole or demi-embryos. Interferon treatment was successful in enhancing lambing rate if injections were given twice daily from Days 11 to 18, 12 to 14, 12 to 15 or 12 to 16. Overall, the lambing rate for ewes bred via natural service was 94/126 (74.6%) for control ewes and 101/126 (80.2%) for rBoIFN-alpha treated ewes. Litter size was not affected by treatment. Interferon treatment was not successful in increasing the lambing rate if given as a single injection on Day 12 or as a series of once-daily injections from Days 11 to 16. These results demonstrate that rBoIFN-alpha can increase the lambing rate in ewes.