Making the most of milk lag times

Optimising lag times between preparing cows’ teat and attaching the cluster offers many producers an opportunity to reduce milking times.

A 60-90 second lag time is ideal, Ian Ohnstad, milking technology specialist for the Dairy Group, explained to a Dairy Circle audience.

This will ensure the cow is ready to let down milk, which requires the hormone oxytocin to stimulate milk flow, when the cluster is attached.

“Many people think a cow leaking milk is stimulated and ready to milk out, but the oxytocin response hasn’t happened.

This is only the milk in her alveoli and when you put the cluster on eight out of 10 cows will stop milking for 40-50 seconds before a proper milk flow is re-established.”

When a cow is stimulated properly she will milk out quickly, said Mr Ohnstad.

Often milkers prepare the teats of a row of cows walking one way down the parlour and then attach the clusters on their way back.

“This means the lag time is from 15 seconds to many minutes.

But preparing five or six cows, then going back and attaching the clusters will lift average flow rates and the cows will milk out faster.

“Once this is achieved you can look at the automatic cluster removal settings and take the clusters off earlier.

This can save minutes milking each cow.”

Other factors that slow down milking include feeding cows in the parlour, he said.

“Where cows are fed in parlour they are slower to come in and slower to go out, plus they tend to be more disruptive during milking.”

He thinks bigger advantages in cow flow will come from automation, including a backing gate – which alone can save many seconds a cow.

Where cows are fed or recorded in the parlour, he reckons automated identification will also save time and this can allow automated shedding at the parlour exit.

Teat preparation was also an area worth looking at to reduce milking times.

But he warned this must not compromise milk quality.

“However, when you are spending 6-8 seconds a cow every day on preparation it means cows are coming into the parlour too dirty, so look at addressing this outside the parlour.”

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