New dry cow advice supports selective use

New Zealand dairy farmers already rank among the lowest users of antibiotics worldwide. But with growing concern around antimicrobial resistance, it’s important to keep improving. Responsible antibiotic use supports sustainable, competitive dairying and protects herd health now and in the long term.

Farmers and vets have been working together to reduce antibiotic use, helping to ensure these important tools remain effective for the future. It’s a proactive move to protect animal health and avoid the kind of worm resistance issues seen in the sheep sector with triple drenches.

Blanket (or whole herd) antibiotic dry cow therapy (DCT) is no longer common practice, with many farms already shifting to selective DCT, and recent New Zealand research backs this shift. Extensive data found that only herds with a bulk milk somatic cell count (BMSCC) above 250,000 – and rising by more than 50,000 in the final three months of the season – benefited from using blanket DCT. This is likely to be fewer than 5% of herds.

“For herds that aren’t experiencing those numbers, their best option is selective DCT for qualifying cows, combined with internal teat sealants for all cows to reduce the risk of new infections,” says Mitch Cooper, veterinarian and DairyNZ senior technical and policy advisor.

“Clinical mastitis records, herd test results, and rapid mastitis testing (RMT) at dry-off provide the main data for selective DCT. Other diagnostics from testing the milk of infected cows to find out which pathogen (“bug”) is involved can support these decisions, but are best used as supplementary tools.”

Expectations for vets are changing too, with tighter prescribing guidelines reflecting the evidence. Working closely with your vet ensures the right cows receive the right treatment at the right time.

For further information, talk to your vet or check out dairynz.co.nz/dry-off