The calfhood disease with the longest-lasting impact on lifetime performance is – hands down – pneumonia, according to Carrie Bargren, practicing dairy veterinarian at River Valley Veterinary Clinic, Plain, Wis.
“A calf that has had pneumonia, even if she has recovered with treatment, will be 2.4 times more likely to have impaired growth in the first 6 months of life,” said Bargren. “She also will be 2.4 times more likely to die between the ages of 3 months and 2.5 years, and there is the same risk that she will calve 2 months later than her healthy herdmates.”
Bargren explained there are three categories of pneumonia in calves:
- Aspiration – This form of pneumonia occurs when any solid material is inhaled and enters the lungs. The most common cause is improper use of esophageal feeders when administering colostrum. Aspiration also may occur during a difficult birth when a calf inhales some meconium (first manure) or amniotic fluid. A common source of aspiration in older calves is nipples with holes that are too large, which allow calves to consume milk too quickly.
- Bacterial – The three primary organisms that cause bacterial pneumonia in calves are Pasteurella multocida, Mannheimia hemolytica, and Mycoplasma species. “Bacterial infections that occur in the first few days of life result from infection within the dam, aspiration or contaminated colostrum,” said Bargren. “As calves grow older, new infections typically are acquired from the environment or other sick calves.”
- Viral – BRSV, IBR, PI3 and BVDV all can instigate pneumonia in calves. “A viral pneumonia then predisposes calves to acquiring bacterial pneumonia,” said Bargren.
Bargren advises her clients to take the following measures to prevent pneumonia in young calves:
- Vaccination – Dry cows can be vaccinated for virtually all of the viral pathogens that cause pneumonia, and the antibodies for them then can be transferred to calves via colostrum. In addition, she said, “a good intranasal vaccine at birth will stimulate the tissues in the airways to make antibodies and be ready to kill respiratory pathogens before they enter the body, providing additional protection for the calf for 4-6 weeks.” She suggests a booster of intranasal vaccine at weaning.
- Colostrum delivery – Colostrum is the only immune protection calves have for the first few weeks of life. Bargren recommends feeding 4 quarts within 6 hours after birth, and monitoring colostrum quality with a refractometer. Checking calves for total proteins (TP) to screen for Failure of Passive Transfer (FPT) of immunity is advised to monitor colostrum management.
- Housing – “Clean air and deep bedding are the most important factors in preventing disease through housing management,” said Bargren. “Proper ventilation systems in calf barns will bring in clean air and remove contaminated air.” She recommends at least 26 square feet of resting space for calves in hutches or individual pens, and at least 30 square feet per head in group pens. Regardless of type, she said shelter systems should protect calves from extreme heat, cold, wind chill, rain, dust and aerosolized pathogens, all of which can stress immunity.
- Nutrition – “Proper nutrition is required for healthy growth rates and to sustain immune function,” said Bargren. “Adjust volume to accommodate for cold temperatures.”
Bargren noted a routine screening program is necessary to detect pneumonia in young calves, especially because their early clinical signs usually are very subtle. “An ideal time to watch for respiratory disease is feeding time,” she suggested. “A newly sick calf will be slower to drink or too uncomfortable to lie down afterward.”
To improve respiratory disease detection and monitor treatment efficacy, Bargren recommends using the Calf Health Scorer app from the University of Wisconsin School of Veterinary Medicine.