A Study of Stillbirths in a Herd of Range Cattle

Abstract

Stillbirths occurring in the beef herds at the U. S. Range Livestock Experiment Station totalled 316 from 8857 births (3.6%), for the period 1936–57 inclusive. Although there did not appear to be any single major causative factor the following characteristics were noted in the stillborn calves: A significantly higher number of males than females were stillborn. Live calves averaged heavier at birth, deviated less from the mean and fell within a narrower birth weight range than did stillborn calves. A significantly higher number of stillborn calves were recorded during first births than in subsequent births, and a significantly higher proportion were above the mean birth weight. A significantly higher number of calves were stillborn in the inbred population than in the test population of the study herds. Posterior presentations and twinning resulted in a proportionately higher than average percentage of stillbirths. Few lethals were identified but the lack of a positive diagnosis of causative factors in a number of the stillbirths leaves this problem open to question.