PROJECT SUMMARY:
At the 1998 white rhino workshop in San Diego reproductive problems
in white rhinoceroses have been defined as:
1) acyclicity and variable estrous cycle length of 35 or 70 days
2) mating failure due to acyclicity, or silent estrus due to sibling
relationship/mate choice problems
3) conception - pregnancy failure due to presumed uterine pathology
Although reasons for these problems could not be identified definitively,
this multi-disciplinary, multi-institutional research proposal aims
to work on possible solutions. Our combined approach to enhance
breeding and overcome reproductive problems includes:
1) endocrine monitoring;
2) transfer of animals to enhance natural breeding;
3) development of artificial insemination (AI).
Serial fecal reproductive monitoring will provide the baseline on
which management and therapeutic measures can be evaluated (samples
from >25 females will be included). The EEP recommendation is
to initially transfer adult animals between zoos in order to break
up sibling relationships/overcome mate choice problems.
The effect of transfers and the new social environment on estrous
cycle activity will be monitored by fecal steroid analysis.
Recent
transfers of rhinoceroses between EEP institutions have resulted
in offspring of previously non-breeding animals, however, according
to literature, a portion of transfers will probably not result in
natural breeding within 30 months after transfer. Therefore another
option for the enhancement of breeding, development of artificial
insemination, will be considered after initial endocrine monitoring
and transrectal ultrasonographic health assessment of the female's
genital tract.
Ovulation induction relying on an established protocol will be used
for optimal insemination timing and effectiveness of this treatment
will be monitored by transrectal ultrasound. For each AI semen will
be collected from two bulls by use of electroejaculations. Preliminary
results demonstrate that an AI technique suitable to
overcome difficult anatomical structures of the female genital tract
is available and this approach will be used and further adapted
in subsequent AI attempts.
