Blackleg cases prompt warning to vaccinate

Farmers have been warned to vaccinate stock against blackleg after a disease-surveillance service detected a rise in the number of cases.

The Agri-Food and Biosciences Institute (AFBI) said the rise had been seen in post-mortem submissions from farms in Northern Ireland over recent weeks.

See also: Vet Viewpoint: Blackleg, scours and heifer selection

The organisation carries out research and analytical testing, and advised farmers to “ensure they vaccinate stock against what is a preventable disease”.

“Blackleg is nearly always fatal, killing stock within 24 hours of the symptoms first appearing,” an AFBI spokeswoman said.

It is caused by the soil-borne bacterium Clostridium chauveoi, which is ingested by grazing cattle and sheep.

Once it has been ingested, the bug produces spores that lie dormant within the muscles.

“When conditions are ideal for the organism – for example, when muscle is damaged, the spores undergo activation, the bacteria multiply and produce a potent toxin.

“The toxin results in the characteristic muscle lesions and typical carcass changes before death,” the spokeswoman said.

Due to the severe nature of the disease, there is often no opportunity for treatment and the affected animal is submitted for post-mortem with a history of sudden death.

“Yet clostridial vaccines are relatively inexpensive and highly effective in preventing occurrence of the disease,” the spokeswoman said.

“We advise all cattle farmers to discuss vaccination regimes with their vet.

“Farmers should also consult their vet immediately in cases where blackleg is suspected, and advice sought on both diagnosis of the suspected case and possible preventive actions in relation to the remainder of the group,” she suggested.