Induction of cyclical ovarian activity in seasonally anoestrous
Romney ewes: studies with exogenous GnRH or LH
K.P. McNatty, K. Ball, N. Hudson, M. Gibb, D.C. Thurley
Wallaceville Animal Research Centre, Upper Hutt
Proceedings of the New Zealand Society of Animal Production.
1982, 42: 21-24
The aim of the present study was to establish whether ovulation
and normal corpus luteum function could be induced in anoestrous ewes by
supplementing the endogenous level of luteinizing hormone (LH) and
whether cyclical ovarian activity could be induced and maintained in
seasonally anoestrous ewes by an unvarying long-term intravenous pulse
regime of gonadotrophic releasing hormone (GnRH), 500 ng once per 2 h or
43-80 days.
The results demonstrated that a normal ovulation can be induced in
anoestrous ewes with LH alone and that the aforementioned GnRH regime
was successful in inducing cyclical progesterone activity. These
findings suggest that normal breeding activity may be restored to
anoestrous ewes when the frequency of hypothalamic GnRH is increased
from an apparent endogenous level of secretory episode per 3.5 h to 1
episode per 2 h.
Keywords: NZSAPAB;
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Last Updated 03-05-1997
