Pregnancy diagnosis and progesterone levels in cows' milk
Laing, J.A.
Veterinary Record 99(10): 188
1976
ISSN/ISBN: 0042-4900 PMID: 969177 Document Number: 104794
It is pointed out that assaying progesterone levels in milk for pregnancy diagnosis does not distinguish between levels in mid-cycle and pregnancy but can be used to detect the trough of progesterone production in non-pregnant animals. Accuracy of negative assays (which indicate that a fully active corpus luteum is not present) and positive assays is discussed; the value of the assay lies in the detection, 21-24 days after breeding, of animals which are not pregnant but which have not been seen in oestrus. It may be employed also to investigate other forms of infertility and to detect animals inseminated at the wrong time. Successful use of the assay in the management of fertility depends on its integration with breeding records, clinical examination and the treatment of abnormal animals.