Understanding and exploiting the physiology and endocrinology of
reproduction to enhance reproductive efficiency in cattle
W.W. Thatcher, P.J. Hansen, C. Plante, L. Badinga, J. Van
Cleeff, G. Danet-Desnoyers, J.D. Savio, M.A. Mirando, F.W. Bazer
Departments of Dairy and Animal Science, University of Florida,
Gainesville, Florida 32611-0701, USA
Proceedings of the New Zealand Society of Animal Production.
1990, 50: 109-122
The bovine conceptus induces an array of physiological and
biochemical responses that lead to the establishment of pregnancy.
Among the most studied of these is secretion of prostaglandin (PG)
F2alpha (F) from the uterine endometrium. Pregnancy appears to be
associated with laterations in many of the regulatory systems that cause
PGF secretion leading to luteolysis in cyclic animals. The conceptus
secretes an antiluteolytic protein (bovine trophoblast protein-1 complex
[bTP-1] that appears to induce an inhibitor of prostaglandin synthesis.
The bTP-1 antiluteolytic protein is an alphaII interferon. The
secondary effects associated with interferon-like activities (antiviral,
antiproliferative, altered gene expression, immunosuppressive) may
complement development and sustenance of the conceptus. Both ovarian CL
function and follicular activity are altered in early pregnancy.
Changes in follicular activity may reinforce the antiluteolytic signals
from the conceptus leading to maintenance of the CL. Potential
management systems to improve reproductive efficiency that are based on
supplementation with bTP-1-like molecules, controlled ovarian follicular
management, and progesterone therapy are discussed.
Keywords: NZSAPAB;
Cattle; conception; follicles; bovine trophoblast protein-1;
progesterone; oxytocin; GnRH agonist
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Last Updated 25-01-1997
