Reproductive Steroids in Deer. III. Luteinizing Hormone, Estradiol and Progesterone around Estrus1

Abstract

Levels of luteinizing hormone (LH), estradiol and progesterone in serum were measured in 6 penned adult female white-tailed deer (Odocoileus virginianus borealis) from 10 days before estrus through 9 days after breeding. Progesterone decreased from ∼7.5 ng/ml 7 days before estrus, to<1 ng/ml around estrus and then rose to 5.1 ng/ml by 9 days following breeding. Estradiol levels fluctuated widely between 9 and 4 days before estrus, but increased significantly from 5.3 ± 0.4 pg/ml to 7.0 ± 0.6 pg/ml (P<0.01) between 3 days before estrus and its onset. The estradiol/progesterone (E/P) ratio rose 3 days before estrus and peaked at estrus. LH levels rose sharply from<1 to 26.4 ± 8.9 ng/ml on the day of estrus and returned to <1 ng/ml by the next day. The temporal relationships between LH, estradiol and progesterone in deer around estrus appear quite similar to those in domestic ungulates.