Use of Treatment Records and Lung Lesion Scoring to Estimate the Effect of Respiratory Disease on Growth during Early and Late Finishing Periods in South African Feedlot Cattle

Abstract

Bovine respiratory disease (BRD) is the most important disease of feedlot cattle worldwide, which, even in its subclinical form, negatively affects calf growth and therefore feedlot profitability. In order to accurately estimate the impact of BRD in the feedlot, it is necessary to account for both clinical and subclinical disease. Although most clinical cases occur during the first 3-6 weeks after arrival at the feedlot, the various persistent lung lesions may affect growth for a longer period of time. However, the effects of lesion type and extent and the time period during which they affect growth are uncertain. This study was done to estimate the effect of clinical and subclinical BRD, lung lesion type and lung lesion extent on growth during the early and late finishing period in South African feedlot calves.