Dynamics of antibodies to Mannheimia haemolytica in veal calves in Belgium

The observational field study was performed on a total of 3497 calves on ten veal farms (6 Holstein Friesian (dairy), 2 Belgian Blue (beef) and 2 crossbreeds) in the North of Belgium. Jugular blood samples were taken from 250, convenience selected, calves (25 per farm) at arrival (14 days of age) and 6, 12, and 24 weeks thereafter. The samples were tested for the presence of antibodies specific for M. haemolytica by an in house ELISA.