Presentations during the recent Academy of Veterinary Consultants meeting reviewed research with BRD-caused mortality in young calves. The mix of pathogens involved in preweaning BRD is similar to older calves. Diagnostics labs find Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, mycoplasma and coronavirus, usually in association with at least one other pathogen.
Two seasonal peaks in the incidence of BRD were observed by researchers. One occurs from birth through around 20 days of age. Another takes place when calves reach 70 to 100 days of age. Researchers believe the early spike relates to a failure of passive transfer of immunity from the dam, and the next peak at three to five months occurs as maternal antibodies decline.
Source: Bovine Veterinarian, May 21, 2019. Link. Timely vaccination for cows and calves plays a key role in preventing preweaning BRD, but good management practices, including cow nutrition during gestation and ensuring the calf receives adequate quantity and quality of colostrum, are critical in supporting calf response to a vaccination program.
INSIGHTS: This is a good article to share with beef and dairy producers. Note the BRD risk associated with three management practices:
- Herds with 500 or more cows
- Operations using intensive grazing
- Operations that synchronize cows and heifers for breeding