Low-N genetics, plantain deliver healthier milk

A four-year study by Dr Cameron Marshall and Professor Pablo Gregorini's team assessed milk from cows that were fed either plantain or ryegrass, and selected for either low or high milk urea breeding values.

The results suggest that both the diet and the low-N genetics help produce milk with a chemical profile beneficial to human health.

Milk produced by cows eating plantain contained a better ratio of omega 3 to 6 fatty acids, as well as a metabolomic profile that has been related to the reduction of stress, inflammation and the growth of cancerous tumours in humans.

The cows selected for low milk urea breeding values also produced milk containing healthier fats, as well as a special metabolite potentially related to lowering anxiety.

Gregorini says those cows urinate more frequently and have a lower concentration of nitrogen in their urine, potentially reducing N loading on Canterbury farms by 30%.

He calls it a "win-win situation: good for the environment and potentially good for human beings".

It means farmers have two tools "available right now" that can not only dramatically reduce environmental loading but also arguably add value to their product.

"If I offer you a glass of milk and you know that glass came from this cow as compared to any other one, and this cow eats plantain but not the other one, which one are you going to pick?"

At this stage the research has only looked at the composition of the milk, and has not yet extended to studies on its effects in human consumers.

However, the Pastoral Livestock Production Lab has also been evaluating how beef, lamb, and venison from different pastures and grazing managements can similarly affect human health.

Gregorini says those studies involved feeding human subjects meat patties from animals raised on either high- or low- diversity pastures, then monitoring blood levels of glucose, cholesterol and certain inflammatory hormones over the next few hours.

Results that are likely to confirm a beneficial effect of beef fed on diverse pasture are expected shortly.

Gregorini says that depending on suitable funding, similar human trials of the milk from high-plantain/low-N genetics cows could begin later this year.

Meanwhile, Gregorini has established a small research farm known as the Integral Health Dairy Farm, which aims to take a multi-disciplinary approach towards a more ethical and sustainable way of dairying.

The farmlet, at the university's Ashley Dene Research and Development Station at Springston, will hold an open day later this month.

It aims to "lead the way through healthier dairy products and removing the negative connotations".