Maximising milking efficiency doesn’t need to come at the expense of animal health, vet Steve Cranefield, the technical manager of Auckland company, AgriHealth, told farmers at the field day. That was where regular monitoring came to the fore.

“After the cups come off check 50 cows’ teats once a month,” he said.

“Use a torch or headlamp and wear clean gloves because there’s less places for bacteria to grow.

Record the result and compare them with the previous month to see if the situation is better or worse.”

Teats should look and feel smooth and supple, he said. Trigger points for getting expert help were if more than 10% of the teats checked had dry skin or more than 20% had rough teat ends, which harboured more bacteria.

With milking machines using vacuum to milk cows and pulsation to maintain teat health, teat end damage could be the result of a combination of these as well as liner movement and over-milking.

Increasing the pulsation ratio to milk cows faster usually exposed teats to more vacuum but cows could be uncomfortable which delayed their milk let-down.

“Although removing cups early leaves some residual milk this is harvested more efficiently at the next milking, which saves time and reduces the risk of teat end damage and mastitis,” he said.

Clinical mastitis rates should be below five to eight cases for every 100 cows calved and one to 1.5 cases per 100 cows a month during lactation.

Cranefield also dispelled some myths. It was false that all that was required was a drip of spray on the end of the teat.

“You need to get it over the whole barrel of the teat.”

Teats didn’t need to be sprayed as soon as the cups came off but this could happen up to two minutes afterwards.

“The teat canal closes as soon as the cups come off but doesn’t completely close for some time,” he said.

“It can take five to 10 minutes.”

No teat spray was better than any other but glycerine was the best emollient.

“Healthy teats are more important than the type of teat spray,” he said.

There were pros and cons to manual or automated teat spraying.

“Manual spraying is so dependent on the person,” he said.

While automatic teat spraying often saved labour its effectiveness depended on the settings used.