Recent research by the FutureDairy project has shown that fluctuations in milking interval, even in the short term can have a big impact on milk production.

In the trial, those cows that were milked at controlled, irregular intervals had significantly lower short term milk yield, milk fat and protein yields than cows that were milked at the same twice-a-day interval (see table).

These findings have significant implications for automatic milking systems (AMS) where cows move to and from the dairy on a voluntary basis.

Dr Kendra Kerrisk, who led the team said cows at FutureDairy’s AMS averaged two milkings a day during the trial. “Some cows come at the same times every day, but not necessarily at an even 12-hour interval; for example some may have one interval of eight hours and the next at 16. Other cows are much less regular with the times between milking and the number of times they are milked per day,” she said.

Analysis of FutureDairy data from the AMS herd has also shown that cows are at higher risk of getting mastitis if the time between milkings is more than 16 hours.

Dr Kerrisk recommended that managers of AMS farms aim for milking intervals of less than 14 hours.

“The difference in production is large enough to warrant targeting more regular milking intervals in Australian automatic milking systems on pasture-based farms. However the impact of irregular milking is likely to be less for low-producing cows,” she said.

The best way to achieve regular milking intervals in a voluntary milking system is to offer cows their full daily feed allocation in more, but smaller allocations.

“This approach has the potential to encourage more regular cow movement around the farm. The key is to have a 3-way grazing system as it reduces the potential for very periods between milking and creates the opportunity to achieve more regular milking intervals.”

A 3-way grazing system involves setting up the farm layout so that cows can receive three allocations of feed a day, rather than the traditional system of offering two fresh breaks of pasture a day.

The advantages of three-way grazing can be achieved with a number of combinations of feed allocation for example, three fresh breaks of pasture a day or two fresh breaks plus a feed pad with a loafing area.

“Anyone considering installing an AMS should design the farm layout to allow for 3-way grazing, if at all possible.” Dr Kerrisk said.