PLASMA LUTEINIZING-HORMONE AND PROGESTERONE CONCENTRATIONS IN GOATS WITH ESTROUS CYCLES OF NORMAL OR SHORT DURATION AFTER PROSTAGLANDIN-F2-ALPHA ADMINISTRATION DURING DIESTRUS OR PREGNANCY

  • 1 June 1988
    • journal article
    • research article
    • Vol. 49  (6) , 939-943
Abstract
Plasma luteinizing hormone (LH) and progesterone concentrations were compared in does experiencing short-duration estrous cycles and in does with estrous cycles of normal duration. The short-duration estrous cycles were observed immediately after induction of abortion in pregnant does by use of prostaglandin (PG)F2.alpha.. Intramuscular administration of 5 mg of PGF2.alpha. was accomplished in 8 does that were 52 to 63 days into gestation and in 9 cycling does at 7 to 10 days after estrus. In both groups, the mean plasma concentration of progesterone decreased from a luteal phase concentration immediately before to < 1 ng/ml by 24 hours after PGF2.alpha. administration. Of the 8 does that aborted, 6 experienced short-duration estrous cycles, and 4 of these 6 had an LH surge during the time of blood sample collection. The mean time from PGF2.alpha. administration to the LH surge was significantly (P < 0.05) longer in does with short-duration estrous cycles (71 hours) than that in does with estrous cycles of normal duration (58 hours). The mean area under the LH concentration curves was significantly (P < 0.005) less for does with short-duration estrous cycles. Short-duration estrous cycles were associated with delayed preovulatory LH surges of reduced magnitude.