The current humid conditions are predisposing young calves to higher than normal levels of respiratory- related health problems, according to Liam Carroll, a practising vet with the Co. Meath-based Farrelly veterinary practice.

“This is particularly so in cases where ventilation levels in calf rearing units are not adequate,” he said.

“In these instances farmers must ensure that calves are maintained on dry bedding and feeding levels are adequate. Keeping calf pens scrupulously clean is crucially important.”

Carroll pointed out that re-infection within groups maintained in calf rearing units can be a particular problem at this time of the year.

“This will happen if new calves are put into the same air space of an animal that had previously succumbed to a respiratory infection,” he said.

“If the new arrival comes down with pneumonia, the disease can then quickly spread to the other animals already in the calf rearing unit. It takes 11 days for the lungs of a young animal to recover from a respiratory breakdown.  One way round this problem is to treat all affected calves with a long acting antibiotic.

“The current warm weather is allowing bugs to remain in the environment for longer periods of time than would normally be the case at this time of the year.”

Carroll said that vaccination against the RSV and PI3 viruses can play a role in preventing the onset of respiratory problems in calves.

But vaccination is not a substitute for poor calf rearing practises.”

Where the feeding of young calves is concerned Carroll said that offering milk or replacer is very much a case of farmer preference.

“I am aware that many dairy producers with Johne’s affected herds will not feed whole milk to heifer replacements.

“Where replacer is offered, farmers should increase feeding rates slightly, once the weather turns cold. Most of the recommended feeding rates for milk replacer cover a calf’s maintenance requirements only.

“During colder spells a young animal’s nutritional requirements will increase significantly. And calf rearers must take full account of this reality."