Journal of Animal Science, Vol 78, Issue 11 2966-2971, Copyright © 2000 by American Society of Animal Science

JOURNAL ARTICLE

Single daily intramuscular injections of low quantities of recombinant ovine interferon-tau extends luteal life-span in Angora goats

D. O. Kiesling, A. N. Stewart and A. D. Ealy
Lincoln University, Jefferson City, MO 65101, USA. Kiesling@lincolnu.edu

The objective of this study was to determine whether single, daily intramuscular injections of low amounts of ovine interferon-tau (ovIFN-tau) would extend luteal life-span in nonpregnant Angora goats. Female goats were assigned randomly to receive a single daily injection of 1) PBS (control; n = 11), 2) 125 microg/d ovIFN-tau (n = 11), or 3) 500 microg/d ovIFN-tau (n = 11) from d 14 to 20 after estrus. Luteal life-span was defined as the number of days from the synchronized estrus until serum progesterone (P4) declined (< 0.5 ng/mL) and was of normal duration in controls (19.4 +/- 0.3 d) but was increased (P < 0.05) in goats receiving 125 microg/d (23.2 +/- 1.3 d) and 500 microg/d (25.5 +/- 1.2 d) ovIFN-tau. Injection of either ovIFN-tau dose caused an initial decrease (P < 0.05) in serum P4 concentrations relative to controls but did not differ from controls thereafter. Rectal temperatures increased (P < 0.05) following ovIFN-tau treatment until d 18 for goats given the lower dose and throughout the treatment period for those given 500 microg/d. In summary, injections of as little as 125 microg/d of ovIFN-tau extended luteal life-span in goats. This dose caused a transient reduction in serum P4 concentrations and induced hyperthermia.