Extension of Corpus Luteum Lifespan and Reduction of Uterine Secretion of Prostaglandin F_2α of Cows in Response to Recombinant Interferon-τ

Two experiments tested the effect of recombinant ovine and bovine interferon-τ on corpus luteum lifespan, interestrous interval, and oxytocin-induced uterine secretion of prostaglandin F_2α. Cows received intrauterine injections of 100 μg of recombinant ovine interferon-τ plus 1.4 mg of BSA or of 1.5 mg of BSA alone in Experiment 1 and 200 μg of recombinant bovine interferon-τ plus 1.3 mg of BSA or 1.5 mg of BSA alone in Experiment 2. Twice daily injections (0700 and 1900 h) were split evenly between the uterine horns from d 14 to 24 of the experimental estrous cycle via an AI pipette in Experiment 1 and via intrauterine catheters in Experiment 2. On d 17, cows were injected with 100 IU of oxytocin, and plasma was collected for analysis of 13,14-dihydro-15-keto-prostaglandinF_2α. Recombinant ovine interferon-τ extended the lifespan of the corpus luteum (27.5 vs. 19.2 d) and interestrous interval (30.5 vs. 20.6 d) and abolished the oxytocin-induced increase in 13,14-dihydro-15-keto-prostaglandinF_2α, which peaked at 30 min for the BSA control group (210.8 pg/ml). Recombinant bovine interferon-τ also extended the lifespan of the corpus luteum (29.0 vs. 21.4 d) and interestrous interval (31.5 vs. 22.6 d) and abolished the oxytocin-induced increase in 13,14-dihydro-15-keto-prostaglandin F_2α, which peaked at 30 min for the BSA control group (205.6 pg/ml). In conclusion, recombinant ovine interferon-τ and recombinant bovine interferon-τ were effective antiluteolytic agents in cattle.