Research published in the April Journal of Dairy Science indicates that you may be able to increase your herd’s resistance to Johne’s disease via genetic selection.
This study estimated the genetic parameters of antibody response to Mycobacterium avium ssp. paratuberculosis (MAP), the causative agent of Johne’s disease, using data from Minnesota Dairy Herd Improvement milk ELISA tests. The researchers found heritabilities ranging from 0.0645 to 0.0946 for antibody production to MAP using this routinely collected field data. These results indicate that it is possible to compute genetic evaluations for resistance to Johne’s disease. In the absence of genetic evaluations for resistance to Johne’s disease, selection for productive life and net merit will result in cows genetically more resistant to the disease.
The desirable correlations reported may have a common underlying cause, the researchers note. Cows that have genetically superior immune systems may be more resistant to MAP infection. These cows with superior immune systems would also be expected to remain healthier to produce more fat and protein, have lower somatic cell count scores, higher pregnancy rates, longer productive lives and more total economic merit.