Antiprogesterone reversal of progesterone-induced rapid transport of ova in superovulated cattle

THERIOGENOLOGY ANTIPROGESTERONE REVERSALOF PROGESTERONE-INDUCED RAPID TRANSPORTOF OVA IN SUPEROVULATED CATTLE B.L. McBride,E. Bessoudo,M.J. bwen, D.C. Kraemer Departmentof VeterinaryPhysiologyand Pharmacology Texas AgriculturalExperimentStation Texas A&M University CollegeStation,Texas 77843 USA A synthetic steroid (RU 486) that has antiprogesterone properties has been shown to have a high affinity for the uterine progestinreceptorin severalmammalian species. This experimentwas designed to evaluate the effect of RU486 on progesterone induced rapid transportof ova throughthe oviductof superovulated cattle. Eight cycling Holstein cows were superovulatedon day 9-13 of their estrouscycle with twice daily decreasingdoses of FSH (6.5, 5, 4, 3 mg). On the 5th and 6th injections of FSH the cows received 25 mg of PGF . All cows were administered 30 mg of progesterone (Reprogest,i nthony Products) at 12 hour intervals at the time of artificial insemination beginning 48 hours after the first PGF injection. Four treatment cows received .I mg/kg of RU486 intramuscularly along with the progesterone injections, plus an additional injection 12 hours later. Each cow was subjected to surgicalembryo collectionfrom the oviducts, uterotubal junctions (LJTJ), and uterinehorns approximately96 hours after the first PGF2 injection. Uterine E&X5 Ovulation recovery Oviduct UTJ horn Fert. Ovulations rate (%) (I) (%) (%) (%) 51

69

20c39ja

13(65ja l(5) 6(30Ja 14(70)

Treatment 47

59

42(89P

38(90+

Control

4(10)

ob

32(76)

apbValuesin a columnwith differentsuperscripts differ (P < .Ol). The resultsdemonstratethat the total number of eggs collected in thetreatmentgroup (42)was higher (P < 0.01)than the total for control (20). The total number of eggs recoveredfrom the oviducts of the treatment group (381, was higher (P < 0.01) than in the control group (13). Egg recoveryfrom the uterinehorns favoredthe control group (6) when compared to (P < 0.01)the treatment group (0).The majorityof eggs in the treatmentgroup were collectedfrom their expected region of the reproductivetract, and therefore,it appearsthat the antiprogesterone steroidwas effectivein reversing rapid transportin superovulated cows inducedby progesterone. Antiprogesteronesteroid was donated by Roussel-Uclaf,St. Denis, France,and this researchwas supportedin part by GranadaGenetics, Inc., Marquez, Texas.

170

JANUARY

1986VOL. 25 NO. 1