Submitted to: Review Article
Publication Type: Review Article
Publication Acceptance Date: 1/30/2008
Publication Date: 2/16/2008
Citation: Karcher, E.L., Beitz, D.C., Stabel, J.R. 2008. Parturition invokes Changes in Peripheral Blood Mononuclear Cell Populations in Holstein Dairy Cows Naturally Infected with Mycobacterium avium subsp. paratuberculosis. Iowa State Animal Industry Report 2008. A.S. Leaflet No. R-2306. Interpretive Summary: Johne's disease is a chronic, debilitating intestinal disorder in cattle characterized by diarrhea, reduced feed intake, weight loss and death. Cattle usually become infected as young calves by ingesting feces containing the causative bacteria. However, symptoms of disease do not usually present themselves until the animals reach 3 to 5 years of age or even older. Clinical signs of disease may be precipitated by stressors such as parturition, heavy lactation, concomitant viral or bacterial infections, and malnutrition. It is well known that parturition causes cows to become immunosuppressed and makes them more susceptible to infections such as mastitis and metritis as well as other viral and bacterial pathogens. The present study was designed to evaluate the effects of the periparturient period on host immunity in healthy cows and naturally infected cows with paratuberculosis. Parturition decreased host immunity in cows regardless of infection status. In addition, paratuberculosis resulted in changes in host immunity compared to healthy noninfected cows. These results suggest that the periparturient period is a highly significant period for the dairy cow and may result in increased susceptibility to infectious diseases.
Technical Abstract: Twenty-one multiparous and two primiparous Holstein cows were grouped according to infection status with Mycobacterium avium subsp. paratuberculosis (MAP), the causative microorganism for Johne’s disease (JD). The effect of parturition and infection on the percentages of CD4+, CD8+, and T-cells, B-cells, and monocytes, in the peripheral blood were monitored. The data suggest that changes in the percentages of lymphocyte subsets and monocytes are modulated by both infection status and the periparturient period.