Da. Hosack et al., Stag exposure advances the LH surge and behavioral estrus in Eld's deer hinds after CIDR device synchronization of estrus, THERIOGENOL, 51(7), 1999, pp. 1333-1342
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.