Postpartum Estrus as an Indicator of Reproductive Status in the Dairy Cow

Abstract

Reproductive performance of 577 cows of the Florida Agrieul~rral Experiment Station dairy herd was evaluated from 1959 to 1968. Following 1,398 parturitions, 1,209 pregnancies occurred and 189 cows were sold for various reasons without having been diagnosed pregnant. Percentages of cows exhibiting standing heat before 60 days postpartum were: 0 heats, 25.9~; 1, 38.7~; 2, 28.0~; 3, 7.2%; and 4, .35. No cow was bred until 60 or more days postpartum. Average services required per conception for the five groups were 2.60, 2.58, 2.32, 2.21, and 1.75, a significant decline. Overall services required per conception were 2.48. Rates of nonreturn to first service increased with number of heats. Cows exhibiting one or more standing heats during 0 to 30 days postpartum required fewer services (2.29) than did cows with no heats during O to 30 days (2.63). However, incidence of standing heats (0, 1, or more) during 31 to 60 days was not related to subsequent reproductive performance. In addition, cows sold nonpregnant experienced fewer postparturn heats during 0 to 30 days and overall than did those which became pregnant.