Record Details

Evaluation of oestrus observation and conception rates in suckling beef cows using whole milk progesterone concentration

Journal of the South African Veterinary Association


 
 
Field Value
 
Title Evaluation of oestrus observation and conception rates in suckling beef cows using whole milk progesterone concentration
 
Creator Lourens, D.C. Thompson, P.N. Bertschinger, H.J. Ameen, M.
 
Subject — Milk Progesterone; Oestrus Observation; Suckling Beef Cows
Description A 2-sample regime was used to measure whole milk progesterone concentration on the day of oestrus and insemination (Day 0) and 6 days later (Day 6) in a sample of 50 primiparous and 100 multiparous suckling beef cows. Exposure to teaser bulls and observation by cattlemen identified the occurrence of oestrus. Three sets of criteria used to define ovulatory oestrus were compared : a) milk progesterone concentration less than 6 nmol / l on Day 0 ; b) milk progesterone less than 6 nmol / l on Day 0 and rising to greater than 6 nmol / l on Day 6; c) milk progesterone less than 6 nmol / l on Day 0 and rising to greater than 6 nmol / l on Day 6, or cow diagnosed pregnant to 1st insemination. Using only a single milk sample on Day 0 (criterion a) would have resulted in the positive predictive value of heat detection being estimated at 98.7%. Using a paired measurement (criterion b) resulted in a significantly lower estimate of 84.7%. The inclusion of cows that conceived despite not showing a marked rise in milk progesterone concentration (criterion c) resulted in a more accurate estimate of 89.3%. Use of a 2-sample regime also allowed calculation of conception rates while eliminating the effect of heat detection errors. In the cows sampled, of those in ovulatory oestrus that were inseminated, 73.1% conceived to the 1st insemination. These results demonstrate that artificial insemination within a limited breeding season can be successful if nutrition is optimal and management is intensive. The use of a 2-sample milk progesterone test may be a valuable tool in investigating heat detection and conception problems in beef herds in which artificial insemination is used.
 
Publisher AOSIS Publishing
 
Contributor
Date 2002-07-06
 
Type — —
Format application/pdf
Identifier 10.4102/jsava.v73i4.585
 
Source Journal of the South African Veterinary Association; Vol 73, No 4 (2002); 190-194
 
Language en
 
Coverage — — —
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