Stag exposure advances the LH surge and behavioral estrus in Eld's deer hinds after CIDR device synchronization of estrus

The impact of male presence or absence on the timing of the preovulatory LH surge and estrus was studied in 3 experimental groups (n = 6/group) of Eld 's deer hinds pretreated with intravaginal progesterone-releasing devices ( CIDR-type G) as follows: Group 1 = indirect male contact barn; Group 2 = di rect male contact barn; and Group 3 = male isolation barn. For all hinds, t he duration of the preovulatory LH surge averaged 2.5 +/- 0.5 h, whereas me an peak preovulatory and basal LH concentrations were 2.9 +/- 0.2 ng mL(-1) and 0.27 +/- 0.03 ng mL(-1), respectively. Nine of 12 male-exposed hinds e xhibited a preovulatory LH surge within 24 to 32 h postCIDR device withdraw al, whereas 0 of 6 male-isolated hinds exhibited a preovulatory LH surge du ring the same time period. Onset of behavioral estrus (45.2 +/- 2.3, 52.7 /- 5.7, and 66.3 +/- 1.8 h, respectively) was significantly advanced (P < 0 .05) after CIDR device withdrawal in male exposed hinds (Groups 1 and 2) co mpared with male isolated hinds (Group 3). These data suggest that stag exp osure is important for modulating the timing of the preovulatory LH surge a nd behavioral estrus after synchronization of estrus with exogenous progest agens. (C) 1999 by Elsevier Science Inc.