Effect of Intrauterine and Intramuscular Administration of Recombinant Bovine Interferon α1 on Luteal Lifespan in Cattle

Intrauterine and intramuscular administration of interferon was tested for effectiveness in extending luteal lifespan in cattle. Intrauterine infusion of 1mg of recombinant bovine interferon-alphaI1, twice daily, to lactating dairy cows from d 14 to 21 after estrus extended interestrous interval (30.4±1.91 d versus 24.8±.58 d) and functional lifespan of the corpus luteum (28.4±2.01 d versus 23.6±.75 d). In another experiment, twice daily intramuscular injection of 20mg interferon to Simmental heifers from d 15 to 19 extended interestrous intervals (24.6±1.36 d versus 20.6±.49 d) and functional lifespan of the corpus luteum (23.2±.37 d versus 20.2±.73 d). In a third experiment, pubertal dairy heifers received twice daily intramuscular injections of 0, 2.5, 5.0, or 10.0 mg/injection of interferon from d 14 to 21 after estrus. The three interferon-treated groups had longer interestrous intervals and functional luteal lifespans than the control group. Interestrous intervals were 22.0±.68, 24.0±1.14, 24.6±1.17, and 25.4±.97 d, respectively. The present data strengthen the theory that an interferon-alpha-like molecule can regulate luteal function in cattle. Such a regulatory compound might prove useful in schemes to reduce embryonic mortality caused by aberrant secretion of embryonic interferon.