Pneumonia can hit calves at anytime and appears to be worse than expected on many farms going by the results from a new report from the National Youngstock Survey, which claims almost two thirds of calves can be hit by the disease at less than six weeks of age.

The survey, carried out by MSD Animal Heath, also found that one in five could be affected at just 10 days of age.

The disease, which has been known to reduce weight gain in beef calves by 202g per day from birth through to slaughter and milk yields of up to 509litres in the first lactation, can however now be detected at a younger age, using thoracic ultrasound scanning.

According to Galloway Group vet, Jimmy More, visually sick calves may only be the tip of the iceberg, as symptoms are not always detected by eye.

He pointed to a study carried out in 2016 looking at the on farm use of ultrasonography for bovine respiratory diseases which showed 11-16% of calves showed clinical signs of pneumonia in one batch. However, anywhere between 23 and 67% could be sub-clinical when thoracic ultrasound scanned.

“Ultrasound scanning uses high frequency sound waves to capture live images on internal body organs and we are now able to offer thoracic ultrasound scanning (TUS) of lungs to help visualise the true impact of pneumonia in calves.

“TUS acts as an excellent tool to assess total lung damage both clinical and subclinical but it should be used as part of a holistic management and preventative programme,” said Mr More.

Similar to a standard ultrasound scanner more commonly used in fertility work, he added that scanning a number of calves between four and six weeks of age – the key time for lung damage – and comparing the results to treatment records, would give producers an idea of just how much of a problem respiratory issues are on farm.

If lung damage is being detected at this stage, he said improved colostrum feeding at a younger age and earlier vaccinations could help. Producers should also ensure calves have sufficient clean, dry straw bedding, and keep different age groups separate. Isolation pens should always be used for sick calves.

“Scanning is not going to fix poor management but once you have colostrum right, the environment is as perfect as it can be, and feeding and hygiene is just right, it gets you to the line.”

Mr More said many farmers think they don’t need to vaccinate because they only treat 2% of calves for pneumonia. But, he said, it was common for herds to have 15% of subclinical cases that go undetected and cause financial losses.

He pointed to a study on six Scottish dairy farms in the spring of 2019, where 193 calves were scanned at between four and six weeks of age (See table 1) and followed up late summer to assess the result of recommended actions and scan a further cohort of 171 calves of the same age (See table 2).

“The aggregate results show an increase in healthy lungs with no lesions and more than a 4% reduction in calves with damaged lung tissue. We also had a farm which stopped using an early life intranasal vaccine and as the result, its lung damage scores increased. However, it has since restarted their early life calf vaccination programme following these results.

“We know vaccination vastly reduces sub-clinical and clinical effects of pneumonia, which when you balance this against the potential lifetime milk yield loss as a result of lung damage caused by the disease, effective vaccination is certainly well worth the investment,” said Mr More.

Although new to UK farmers, TUS is already being used by farmers in America to decide whether or not to breed from a heifer, while farms in Spain are scanning calves in rearing units when they arrive.