Disposing of TB reactor milk is likely to be a case of numbers management and requires a different approach from dumping mastitic milk, warns Glos-based vet Roger Blowey.
With mastitic milk there is the concern of transferring mastitis from one cow to another, he says.
But this doesn’t apply with TB milk as the risk of disease transmission is relatively small.
“In most cases TB is spread from cow to cow via the respiratory route, so it is less important to milk them last and no cluster dip is needed, even when a cow is excreting TB in the milk.”
At the end of each TB test any reactors or inconclusives should be put into isolation from the rest of the herd.
“This means they would normally be milked first or last anyway.
Collection of this milk depends on reactor numbers and available facilities.”
An added problem is that reactor cows can stay on farm for several weeks while paperwork is sorted, which can take longer as herd sizes increase, says Mr Blowey.
Because reactor milk can no longer earn income, he suggests producers consider drying cows off instead.
“It is an extra workload to manage these cows and discard their milk, so it might be better to save hassle and dry them off.
For animal welfare, it would be preferable to use dry cow therapy to prevent mastitis.
However, these cows still go into the food chain, which means a long meat withdrawal period.
“Mid and late lactation cows could be treated with just a teat seal, to save costs.
But the risk of mastitis is greater in early lactation or high yielding cows, in which case a shorter withdrawal milking cow tube could be used.”