Lesions attributed to vaccination of sheep with Gudair™ for the control of ovine paratuberculosis: post farm economic impacts at slaughter

Abstract

To determine i) the prevalence of lesions at the site of vaccination with Gudair, and ii) the incidence of discounting of slaughtered sheep carcasses due to the presence of these lesions. A survey of the prevalence of injection lesions and actual discounts applied to 20 consignments of vaccinates slaughtered in abattoirs in New South Wales. Consignments of sheep previously vaccinated against ovine Johne's disease (OJD) were assessed on the slaughter chain for the prevalence of vaccination site lesions and any costs associated with carcass trimming were estimated. In addition a telephone survey was conducted to determine the experiences and risk attitudes of 8 abattoirs in south east New South Wales likely to have previously processed vaccinates. The prevalence of lesions observed was 18% for adult (mutton) and 65% for lamb carcasses. The value of the trim removed was insignificant, the labour cost of its removal was nil and no carcass was downgraded to a lower value grade. Under the market conditions existing at the time the study was conducted, in sheep vaccinated at the recommended site high on the neck, it is unlikely that OJD vaccination site lesions will be a significant cost to producers or the processing industry and will represent only a very small proportion of the total cost of OJD control by vaccination.