New research by the Department of Primary Industries (DPI) has found that feeding dairy cows the stems, seeds and skins from wine grapes increased milk production, dramatically cuts their methane emissions and makes their milk healthier.
Scientists at DPI’s Centre for Dairy Excellence at Ellinbank found that supplementing the cows’ feed with grape marc reduced their emissions by 20%, increased milk production by five per cent and increased the healthy fatty acids in their milk when green feed was not available.
The cut to emissions is thought to represent the largest reduction of its kind ever attained through the use of a feed supplement. The scientists supplemented the diet of dairy cows with 5kg of dried grape marc over 37 days and compared the results with other animals fed conventional fodder. They then measured the cows’ milk yields, milk composition and methane emissions.
DPI scientist Peter Moate said the researchers were stunned by the results.
Dr Moate said: “We now know that supplementing a dairy cows’ diet with dried grape marc increases the healthy fatty acids in milk by more than six times that of standard autumn fodder. These particular fatty acids are extremely potent in their ability to benefit heart health and are also known to help fight cancer, diabetes and arthritis.”
Dr Moate said at this stage it appeared that a substantial increase in healthy fatty acids by adding grape marc to cows’ diet only occurred 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.”
Dr Moate said there were also early indications that cows fed grape marc also produced milk with higher levels of healthy anti-oxidants and that further tests were being conducted to verify this. He said on top of the cuts to emissions and the potential health benefits for milk drinkers, the discovery could also provide tangible benefits for the wine industry.
“We’ve managed to utilise what is currently a waste product for the wine industry and turn it into a very valuable feed source,” Dr Moate said.
He said there was currently around 200,000 tonnes of grape marc produced in Australia every year making it a readily available product for dairy farmers. However there were limits to the movement of grape marc because of quarantine restrictions to prevent the spread of the grapevine pest phylloxera.
In another benefit to flow from the research, the results also showed that feeding grape marc to dairy cows also increased their daily milk production by 5%. Dr Moate said the trial was carried out towards the end of the lactation cycle and that the researchers hoped to repeat it during early lactation when the cows were producing more milk.
“It’s possible that the benefits of using grape marc as a feed supplement in early lactation could be even more significant,” he said. Dr Moate said the research into using grape marc as a feed supplement was another example of DPI science aiming to enhance the productivity and profitability of Victorian food and fibre producers.
This research is part of a wider program looking the use of feed supplements to reduce methane emissions, such as brewers grains, cold-pressed canola meal, cottonseed meal, and hominy meal, all reduce methane emissions while supporting milk production.
The Victorian dairy industry is the state’s largest rural industry and exports more than 85% of Australia’s dairy products. The gross value of raw milk production in Victoria in 2009-10 was around $1.96bn. In 2010-11, Victoria produced 5.91 billion litres of raw milk from a dairy herd of around 1 million.
Dr Moate said the use of grape marc together with other methane reducing feeds could result in a reduction in methane emissions of up to 20,000 tonnes per year – the equivalent of taking about 200,000 cars off the road.
Source: Department of Primary Industries
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