Economic losses caused by paratuberculosis in a dairy herd: case report.

The impact of clinical paratuberculosis in a 500 cow Jersey x Holstein dairy herd of loose housing system was followed up for three years. There was an increasing fall in annual milk production, namely 49, 474, and 1030 litres per cow, a decrease in the average age from 63.9 to 57.0 months, and of feed conversion from 60 to 39%. The effect of certain management deficiencies, existing throughout the study, is discussed.