Effect of administration of a novel recombinant bovine interferon on length of oestrous cycle in cattle

Abstract In ruminants, extensive reproductive loss occurs during the process of maternal recognition of pregnancy and it has been suggested that trophoblast interferons may be potential therapeutic agents. This paper reports results from a trial using eight first lactation Holstein-Friesian heifers to test the efficacy of a novel recombinant bovine interferon produced in bacteria in extending the life of the corpus luteum. Oestrus was synchronised in these animals and 0·1 mg of this non-glycosylated interferon was infused into the uterus twice daily for 13 days starting approximately 12 days after oestrus. This treatment resulted in an extension of the lifespan of the corpus luteum by 5·5 days (P=0·028) compared with untreated controls. In these animals the interovulatory period was extended by 6·4 days (P=0009). Administration of this protein did not have any adverse effects either on body temperature or on daily milk yields. The results indicate that this novel interferon may have potential therapeutic application for reducing embryo mortality.