Growing Forward 2 - Final Report - Page 16

VEAL CALVES bought as preconditioned calves from western provinces. These bull calves are raised to produce high quality meat, however due to the nature of sourcing these animals, biosecurity and early management practices in place at the birth farm and the stress and exposure to pathogens from commingling during transport and at sale barns, they are at an inherently greater risk of illness and need for antimicrobial use. As in replacement heifers, the stress of shipping calves, combined with the exposure to animals from many different sources, creates a population that is highly susceptible to infectious diseases. The strongest predictor of calf health is proper management of colostrum. This includes testing colostrum immunoglobulin (Ig) levels, ensuring the calf is given a sufficient quantity within 12 hours of birth and then testing the serum Ig level of the calf. Failure of passive transfer is associated with respiratory and gastrointestinal disease, the two most common ailments in calves. Approximately 45 per cent of Canadian veal is raised in Ontario, although production is predominantly of grain-fed veal cattle. College of Veterinarians of Ontario  To combat the stresses faced early in life, antimicrobials are often added to calf milk replacer. This practice can delay morbidity and decrease mortality, as well as promote increased growth and improved feed efficiency. European facilities often give blanket “start treatments” to newly arriving calves. This practice is contentious due to the link between antimicrobial usage and diarrhea. Almost 25% of dairy calves are affected by diarrhea before weaning, making it the number one cause of morbidity and mortality. Antimicrobial therapies may cause diarrhea through disruptions of the normal intestinal biome. The normal biome is likely compromised to begin with, since calves are unable to pick up beneficial microbes from their dam due to early separation. Even if the cause of the diarrhea is not bacterial, it is possible that antimicrobial therapy will be effective, as secondary E. coli overgrowth may develop in the small intestine. However, most drug therapy for mild diarrhea is not beneficial and, in fact, antibiotic treatment may be associated with higher mortality. Respiratory disease is the other major reason for antimicrobial treatment in veal production. 16