Pneumonia risk raised by changeable weather

Farmers with housed calves should guard against pneumonia this autumn because cases are running well ahead of last year, according to surveillance by the National Animal Disease Information Service.

With enzootic pneumonia directly linked to fluctuations in night-time temperatures, and frosty nights and milder days damaging cilia in calves’ tracheae, it is not surprising there is a rise in cases, says Shropshire vet Charlie Lambert.

“November to January is peak time for pneumonia outbreaks, affecting mainly calves up to nine months old. Although there have been cases already, this is not out of line with previous years,” says Mr Lambert.

With clinical pneumonia calculated to cost more than £80 a head for an infected calf and chronic respiratory infections reducing daily liveweight gain and carcass classifications, active steps to prevent and control the disease are worthwhile, says Penrith vet Chris Swift.

“Ventilation is one of the most important aspects in housing to help minimise losses. Buildings should be well ventilated without being too draughty and have at least 15cu m of air space and 8sq m of ridge ventilation for every 100 head,” he says.

“Having the correct stocking density to avoid overcrowding and keeping muck and bedding build-up down can also help preserve the right air space and humidity levels. Reducing stress by weaning, housing and worming on different days can also help.”

West Midlands vet Steve Borsberry also recommends clipping animals’ backs to help dissipate heat and reduce condensation.

Mr Swift advises keeping stable groups of calves to minimise stress levels. “But for farmers having to buy in young stock, buying from a known, reputable source is vital. Knowing calves have received colostrum within the first six hours of life is vital, because this is the best initial protection against pneumonia.”

Mr Lambert adds: “Vaccinating for pneumonia now can also help control levels and, although vaccination is costly, in the long run it far outweighs the cost of a case of pneumonia.

“Currently only about 10% of young stock is vaccinated and it is usually the value of the cattle that determines vaccination. Although this is understandable, longer-term damage can also have significant cost implications. Scar tissue on lungs means animals will be more prone to subsequent respiratory infections in future.”

Mr Lambert warns that vaccination is not an instant fix on farms already seeing cases of pneumonia because it takes a few weeks for antibodies to develop.

But for producers worried about the cost of vaccination, Mr Lambert recommends getting blood tests from a sample of last year’s calves. “Taking blood tests of a sample of last year’s animals will identify what viruses are on-farm from the antibodies detected,” he says. “This will help determine whether you need to vaccinate.”