VACCINATING calves against Mycoplasma bovis significantly reduces post-weaning mortality and antibiotic use, according to results from an independent farm-based trial.

The trial, which looked at growth rates, mortality and antimicrobial usage for 1,582 calves born into eight herds in Scotland, considered the efficacy of a new multi-strain vaccine imported from the US.

“Although the vaccine has proven effective after its recent introduction to the US market, this is the first time we’ve been able to use it in the UK,” said Graeme Fowlie at Meadows Vets, which secured the import license with the help of Dutch pharmaceutical firm Kernfarm.

Mycoplasma bovis has recently become the most common cause of bovine respiratory disease – particularly pneumonia in calves – with other symptoms including mastitis, arthritis and otitis. And it is notoriously difficult to treat.

“It doesn’t respond to most common antibiotics, so prevention is definitely better than cure – but until now the only vaccine available has been a bespoke autogenous one,” added Mr Fowlie.

Given that the multi-strain vaccine is new to the UK market, Mr Fowlie organised a set of trials in Scotland to see how it would work in a real farm environment.

The results have been impressive. In total, weaned calf mortality fell from 5.8 per cent pre-vaccination to 0.4 per cent post-vaccination, whereas it remained relatively unchanged on control farms at 7.3-7.8 per cent.

Due to inconsistent farm records, it was not possible to isolate mortality due to suspected pneumonia, so records for all mortality causes were used.

The results found that pre-weaning mortality increased slightly on treated farms, as one had an outbreak of cryptosporidium and two had problems with colostrum yield and quality.