PROBLEM: Reduction of excess numbers of white-tailed deer (Odocoileus virgi
nianus) is an example of a potential use for immunocontraception as a means
of wildlife population management.
METHOD OF STUDY: A 4 year multifaceted study was conducted to determine the
long term effects of gonadotropin releasing hormone (GnRH) contraceptive v
accine on the fertility and behavior of female and male white-tailed deer.
Deer were monitored for breeding behavior, hormone levels, pregnancy, fawni
ng and GnRH specific antibody levels.
RESULTS: Treatment lead to reduced fawning rates, altered estrus behavior,
reduced concentrations of progesterone, contraception and failure to mainta
in pregnancy following conception. GnRH immunized does bred to untreated bu
cks had an 88% reduction in fawning caused by either immunocontraception or
immunocontragestion. The vaccine effect is reversible, directly related to
the antibody titer. Infertility lasted up to two years without boosting. G
nRH immunized bucks demonstrated no interest in sexual activity when paired
with control females. Depending on the immunization schedule, antlers eith
er dropped early or remained in velvet.
CONCLUSIONS: The results of this study demonstrate that GnRH vaccine is eff
ective in inducing a reversible infertility in white-tailed deer, the infer
tility lasting up to two years without boosting.