Australian study promises sustainable ‘heart-friendly’ milk

13-Dec-2011 - Last updated on 13-Dec-2011 at 09:49 GMT

The DPI found that cows fed a grape marc supplement produced milk rich in beneficial fatty acids

Scientists in Australia say they have conducted new research showing that feeding cows winemaking byproducts drastically cuts their methane emissions and leads to healthier milk.

Researchers at the Department of Primary Industries’ (DPI’s) Centre for Dairy Excellence in the state of Victoria found that supplementing cattle feed with grape marc – stems, seeds, skins from wine grapes – cut methane emissions by 20 per cent.

The measure also increased yields by five per cent, and increased levels of fatty acids in milk, in areas where green feed was unavailable.

The DPI said it believed it had attained the largest emissions cut of its type ever achieved via the use of a feed supplement.

200,000 cars off road

Scientist Dr Peter Moate said the use of grape marc with other methane-reducing feeds could cut methane emissions by up to 20,000 tonnes per year, equivalent to taking 200,000 cars off the road.

The scientists supplemented dairy cow diets with 5kg of dried grape marc over 37 days, comparing the results – yields, milk composition and methane emissions – against indicators provided by the cattle’s normal fodder.

DPI scientist Peter Moate said: “We know now that supplementing a dairy cow’s diet with 5kg of dried grape marc increases the healthy fatty acids in milk by more than six times that of standard autumn fodder.”

Moate said dairy fatty acids were “extremely potent” in their ability to benefit heart health, “and are also known to help fight cancer, diabetes and arthritis”.

But Moate said that it appeared there was only a substantial increases in healthy fatty acids when adding grape marc to diets when green feed was not available.

“However, using grape marc as a feed supplement appears to be extremely effective in increasing these healthy properties during drought or long dry seasons,” he said.

Early indications also showed that cows fed grape marc also produced milk with higher anti-oxidant levels, Moate said, with further tests underway to verify this.

Wider research programme

He added that the wine industry might also benefit from the research, by selling on what is currently a waste product (200,000 tonnes of grape marc produced each year in Australia) as a valuable feed source.

However, the movement of grape marc is limited in Australia, due to quarantine restrictions to prevent the spread of grapevine pest phylloxera.

The DPI is involved in a wider research programme looking at the use of novel feed supplements – brewers grains, cold-pressed canola meal, cottonseed meal, hominy meal – to cut dairy emissions.

The Victorian dairy industry is responsible for 85 per cent of Australia’s dairy products, and the gross value of raw milk production in 2009/10 was around $1.96bn (€1.49m).