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The Influence of Progesterone During Early Pregnancy in Cattle
Author(s) -
Mann GE,
Lamming GE
Publication year - 1999
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.1999.tb01250.x
Subject(s) - biological sciences , library science , physiology , medicine , biology , computer science , microbiology and biotechnology
Early pregnancy in the cow In dairy cattle, failure to conceive to a particular mating represents a major constraint to fertility. Current estimates suggest that in the UK only around 50% of dairy cows calve to a particular insemination indicating that in 50% of cows pregnancy fails. The timing and extent of these losses has been reviewed extensively by Sreenan and Diskin (1 986) and more recently by Peters (1996). These reviews report a fertilisation rate of around 90%. Pregnancy rate then falls to around 80% by day 10-13 due to failed embryo development. By day 19 this figure has fallen to around 60-65% due to failure of the embryo to prevent luteolysis and maintain the secretion of progesterone necessary for its continued development. Thus around 2530% of pregnancies fail due to early embryo mortality. Further late embryo losses of around 510% and an abortion rate of around 5% lead to a final calving rate of around 50%. From these figures, based on a number of studies, it can clearly be seen that the most important factor contributing to early pregnancy failure is embryo mortality. This mortality results partly from the direct failure of the embryo to develop, but more commonly from the failure of the embryo to prevent luteolysis and maintain the pregnancy.