M bovis sees farmers take extra precautions this mating season

As mating season approaches, dairy farmers are weighing up their options in the wake of the Mycoplasma Bovis outbreak.

The disease, which is mainly spread through close physical contact with infected animals, makes using bulls which have been exposed to other stock an added risk.

Dairy NZ said farmers are using a range of tactics including due diligence, quarantine, and virgin bulls, to keep their cows and farms safe from Mycoplasma bovis this mating season. 

This has made some farmers think twice about continuing to use a combination of artificial insemination (AI) and bulls, and consider extending AI to remove bulls from the equation altogether, or reduce the number required.

Dairy NZ response manager Hamish Hodgson said the best thing farmers can do to protect their herd and farm is to do their homework. 

"Unfortunately there isn't a silver bullet, there are pros and cons associated with both AI and bulls," he said. 

"While a lot of farmers have been considering adapting their usual approach, most aren't making drastic changes," Mr Hodgson said.

The majority appear to be sticking with a combination of AI and bulls, despite reports some farmers were shying away from using bulls this season. 

"There's been some murmurs that farmers were going to avoid using bulls and just use artificial breeding, however after considering the risk and the cost to their businesses few have elected to proceed," he said. 

He advises those using bulls to still do their due diligence, check where they've come from and if they've been in herds with a history of disease.  

It's understood there has also been a spike in demand for virgin bulls which have had minimal exposure to other animals, reducing the biosecurity risk of bringing bulls on farm. 

Farmers have also been asking about M bovis tests for bulls. 

"There is a PCR (polymerase chain reaction) test that is highly sensitive and will detect if M bovis is present in a sample, but the complex nature of the disease can make this challenging," he said. 

Dairy NZ recommends farmers using bulls keep them separate from their main herd for at least seven days to allow time for the disease to present itself if they're infected.

Any farmers concerned about the health of bulls should contact their veterinarian before introducing them to their herd.