Milk Progesterone Testing: Application to Herd Management

Abstract

A commercial pregnancy testing service for cows became available to United Kingdom dairy farmers in 1975. The service met an immediate demand from farmers attempting to reduce losses due to delayed conception, $1.20 per cow per day, and after 18 mo approximately 5% of cows were being tested. Approximately one in six (16.5%) of the cows tested, which had not been detected in estrus by 24 days after insemination, were negative to the test; monthly variation was in the proportion of negative tests. Accuracy was 100% for the negative tests in herds where cow identification was good, and 85.2% for positive tests mainly because of fetal loss and insemination during the luteal phase.