No specific research has been carried out to assess the link between bovine tuberculosis (TB) herd breakdowns and the intensification of dairy farming.
Surveillance data routinely collected and analysed by the Veterinary Laboratories Agency indicate that confirmed incidence in dairy herds is no higher than for other herd types when herd size is controlled.
Philips ‘et al’ in their 2000 report on the role of cattle husbandry in the development of a sustainable policy to control ‘M. bovis’ infection in cattle recognise that cattle farming systems have increased in the intensity of production in recent decades, with increased milk yield and growth rates of cattle. However, they draw no conclusions between this and an increase in risk of Bovine TB herd breakdown. This report is available on the DEFRA website.
While there may be a correlation between variables related to the intensification of dairy farming, such as increased herd size and risk of TB (e.g. Goodchild and Clifton-Hadley 2001), TB has a complex epidemiology and due to the number of variables that contribute to the risk of a TB breakdown, it is not practically possible to isolate the direct impact of one measure.
Goodchild, AV and Clifton-Hadley, RS (2001). Cattle-to-cattle transmission of Mycobacterium bovis. Tuberculosis 81 (1/2): 23-41.)