Artificial insemination of cattle based on daily enzyme immunoassay of progesterone in whole milk
Foulkes, J.A.; Cookson, A.D.; Sauer, M.J.
Veterinary Record 111(13): 302-303
1982
ISSN/ISBN: 0042-4900 PMID: 6755876 Document Number: 193122
82 cows that had calved more than or equal to 42 days previously on 4 farms were monitored for 30 days for whole-milk progesterone concentration, and were inseminated on the day after the 2nd of 2 consecutive days for which values were <5 ng/ml. 82 controls in the same 4 herds were inseminated at observed oestrus during the 30-day experimental period. Pregnancy diagnosis was by milk progesterone assay 24 days after AI. For the experimental and control groups, the percentage of cows inseminated during the experimental period was 97.5 and 70.7 resp., the pregnancy rate 62.5 and 47.5% of inseminated cows, and the interval from previous calving to AI averaged 78.3 and 91.7 days.