Tips to avoid this single biggest killer of newly weaned calves.
Source: Merck Animal Health
Don’t let weather fluctuations get the best of your calves. Abrupt springtime temperature swings can weaken immune systems and leave calves at risk for bovine respiratory disease (BRD). And it’s nothing to ignore.
BRD is the single biggest killer of newly weaned calves.1 Lung damage is irreversible and has long-term negative effects on growth, reproductive performance and milk production. 2
Tom Shelton, DVM, senior technical services manager for Merck Animal Health, notes that respiratory problems often occur in month-old calves while they are still in hutches and again at weaning when they move into group housing and are under social stress.
"Weather changes during these high-risk periods can exasperate respiratory problems," says Shelton. "Vaccination can help, but there is no set vaccination program that will work on every dairy."
Shelton encourages producers to work with their veterinarian to determine what pathogens are causing respiratory problems. "Pathogens are constantly evolving and new disease challenges emerging," he explains. "Diagnostic work is the only way to know what to include in a vaccination program and determine the best vaccination timing."
Many pathogens contribute to BRD. Viral pathogens can include parainfluenza, infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus (BVDV) and bovine respiratory syncytial virus (BRSV). Common bacterial pathogens are Pasteurella multocida, Mannheimia haemolytica, Haemophilus somnus and Mycoplasma.
Once pathogens of concern are determined, the vaccine selection process can begin. When it comes to calves and respiratory disease, Dr. Shelton encourages the use of intranasal vaccine for three reasons:
(1) rapid onset of immunity;
(2) reduced concerns of maternal antibody interference; and
(3) the vaccines are easy on calves compared to those given under the skin.
Intranasal vaccines go to work directly in the nose and upper respiratory tracts to provide protection at the point of attack against BRD pathogens. "The majority of infections with disease-causing organisms, like Pasteurella and IBR, begin in the nose," Shelton says. "Administering a vaccine directly into the nasal cavity means the calf can develop a quicker immune response. The vaccine stimulates local protection, preventing disease organisms from attaching and replicating."
With intranasal products, there is also less concern about maternal antibody interference because the vaccine stimulates mucosal immunity – there is no systemic reaction, which occurs when product is administered under the skin.
Shelton adds that intranasal products are usually easier on the calf. "There is less inflammation because of the nasal administration route and that often leads to improved calf performance," he says.
The goal of vaccination is to stimulate the calf’s immune system to ensure adequate protection against BRD prior to the time of disease challenge. However, preventing BRD involves much more than vaccination.
"Vaccination will never replace good management," says Shelton, who offers these health management tips:
• Antibody protection begins at birth. Feed 1 gallon of colostrum within two hours of birth and a second gallon 12 hours later.
• Provide calves with clean, dry bedding and adequate shelter with good air quality.
• Monitor calves and watch for any cause of stress to enable a smoother transition into group housing.
• Train employees to identify and treat BRD at first signs of pneumonia.
1. NAHMS Dairy 2007 Part I: Reference of Dairy Cattle Health and Management Practices in the United States, October 2007. Available at: http://www.aphis.usda. Accessed January 2014.
2. Stanton, A.L., D.F. Kelton, S.J. LeBlanc, J. Wormuth and K.E. Leslie. 2012. The effect of respiratory disease and a preventative antibiotic treatment on growth, survival, age at first calving, and milk production of dairy heifers. J Dairy Sci. 95(9):4950-4960.