M. bovis

The entry of this disease into NZ has impacted hugely on all our farming businesses. It is costing the industry and country a lot of money and causing a lot of worry and reassessment of how we do things. If you want to keep up to date with what is happening you can subscribe to the weekly MPI newsletter on the MPI website or through the links Fonterra and DairyNZ send out. I would encourage you to do this, there is a lot of interesting information available.

We are getting lots of questions around what we are doing in our business this year. We have certainly reviewed everything we do. We now have a Biosecurity Policy and signs in place, with no visitors coming on-farm without going through the footbath etc. All milk bought in this year will be treated with citric acid to drop the pH to 4.5 and kill any potential M. bovis bacterium. Calves will still drink milk at this pH, so we don’t see it having a negative effect on calf welfare. M. bovis is killed if the pH of milk is dropped to 4.3 or lower for 1 hour, or 5 or below for 8 hours. Calf palatability is affected at pH 4 or below.

Citric acid is a reasonably cost-effective way of reducing pH, and is easily handled (gloves, face mask and eye goggles required). We think this is a good safeguard if you are bringing milk in yourselves from other farms and feeding it to your calves. We have purchased our citric acid from Clark Products in the Hawkes Bay, though we are expecting this to be available at Farm Merchant Stores this spring.

We have heard of one calf rearer purchasing a pasteurizer, however this is an expensive option ($35 – $50k ish depending on the size). Thermaflo from Palmerston North seem to be working well in this space. The other option is milk powder, which is completely safe. There could well be supply issues with this again this year, so if you are looking for milk powder, purchase and store this on-farm to ensure supply.