Stag exposure augments urinary progestagen excretion in Eld's Deer hinds Cervus eldi thamin

This 2-year study investigated Eld's deer (Cervus eldi thamin) stag influen ces on ovarian activity of hinds. Immunoreactive urinary pregnanediol-3 alp ha-glucuronide (PdG) excretion was used to characterize ovarian activity pa tterns. Results from Year 1 studies revealed that females exposed to stag u rine increased (P<0.05) progesterone metabolites during the first three est rous cycles of the reproductive season, compared to non-urine exposed hinds . Due to experimental design limitations, the unequivocal importance of uri ne could not be established. Year 2 studies sought to answer a more basic q uestion: Does male presence or absence affect estrous cyclicity in Eld's de er? Compared to hinds maintained in complete isolation from stags, PdG excr etion during the first two seasonal estrous cycles was increased (P<0.05) i n hinds maintained in either a mixed-sex barn setting or housed continuousl y with a single stag. The increase in urinary progesterone excretion during the luteal phase of the estrous cycle was manifested as an increase in mag nitude, rather than an increase in the length of the luteal phase. These da ta suggest that the reproductive axis of female Eld's deer is sensitive to male presence, and suggests a mechanism whereby stags may enhance fertility in hinds.