25 December 1998

Cattle salmonella cases rise

SALMONELLA in cattle is an increasing concern this winter, warn vets

Reporting this increase in UK Vet, Gloucester-based dairy vet Chris Watson has seen salmonella T104, which can also infect humans, on three farms within a month. The bug is widespread and is often present without causing disease.

"Clinically infected animals usually have diarrhoea with blood and mucous, often around calving, or will abort. But one sign easily missed is calves with pneumonia."

Outbreaks may start with one diseased animal, suffering for example from bovine viral diarrhoea. This animal excretes salmonella, causing disease in other animals – sometimes a few weeks later.

By then salmonella will be found all round the farm, on everything from milkers boots to tractors and the farm dog, but disease may only affect a few animals.

"Treating individual animals is successful and vaccination helps build immunity quickly when there are more salmonella cases than are acceptable."

Decontaminating the farm is more difficult, but its important to attempt it. Steam cleaning may make salmonella more active, he warns, dry out pens thoroughly after cleaning.

But cutting risk of an outbreak is possible. Store feed where birds cannot access it, avoid movement of stock between herds and borrowing bulls or tractors, he says. &#42