Producers should not be fooled into thinking the risk of pneumonia in calves disappears as temperatures rise this spring. That’s the warning from Zoetis’ Carolyn Hogan.
Although the overall incidence of pneumonia decreases in spring and summer, as the weather becomes warmer, calves that are housed are still at risk and, therefore, should be protected.
According to the Animal and Plant Health Agency’s (APHA) GB Cattle Disease Surveillance Dashboard, during the winter months from October 2017 to March 2018 there were 522 pneumonia diagnoses compared to 282 diagnoses during the spring and summer months from April to September 2018.
“For most pneumonia cases, samples are not submitted for diagnostics, so these figures don’t tell us the total incidence of pneumonia in the UK,” says Ms Hogan. “But they do tell us when calves are getting pneumonia.
“Around 35% of the pneumonia diagnoses were made between April and September 2018, showing that problems continue during the spring and summer months, and that this isn’t just a winter problem.”
A calf’s susceptibility to pneumonia depends on the strength of its immune system. Key factors that influence immunity include: adequate colostrum quality and intake, which should be given as quickly as possible after birth; nutrition and the management of any dietary changes; management practices; stress, including transportation, sudden feed changes and overcrowding.
Also important factors are the calf-rearing environment, including poor ventilation, high humidity, damp bedding, temperature fluctuations and draughts; and mixing animals of different ages groups within the same airspace.
“Even though the weather is warmer, and less damp and humid, animals that are housed are still at risk from housing factors such as poor ventilation, draughts, and increased pathogen challenge due to close contact with other calves,” says Ms Hogan.
“And in spring there can also be significant temperature differentials between day and night, which increases stress in calves and their susceptibility to pneumonia.”
She adds that vaccination is important in protecting calves against the infectious agents that cause pneumonia. Vaccination works by increasing the calves’ immunity, so they are better able to fight off infection, and reducing the challenge by reducing the amount of virus the calves breathe out.