2011-03-22

Boosting milk production major focus of research

Significantly, increasing milk production is the theme of research being presented by AgResearch scientists at the NZBIO Conference 2011 in Auckland on 21 March 2011, focusing on enabling successful biotechnology.

AgResearch scientists will detail their innovative research aimed at further lifting production in New Zealand’s key export income earner, the dairy industry.

Lead researcher in the Lactation Biology Team, Animal Biosciences Section, at AgResearch Ruakura in Hamilton, Dr Kuljeet Singh, along with a team of scientists, is at the cutting edge of this internationally recognised research.

“We’re trying to understand the complex cellular and molecular mechanisms in the cow’s mammary gland which result in natural increases and decreases in milk production,” says Dr Singh. “This is a complex and relatively unknown area that will make a huge difference to the dairy industry.”

“Many dairy farms only milk once a day, or would like to do so, but this often results in a fall in production. So we’re researching the protein and cell signaling pathways that control the lactation process to see if we can manipulate it to improve milk production.”

Dr Singh says the aim is to determine the nature of the switch or trigger at a cellular level in the cow’s mammary gland, which stops and starts lactation. She says there is a range of environmental influences, for example nutrition, that may cause a chemical change to DNA of mammary glands’ cells. The research focuses on identifying such changes and understanding if these changes could cause epithelial cells of the mammary gland to turn off.

Once these pathways are determined then this opens up the possibility of altering a cow’s nutrition, providing supplements or other manipulation which will influence and enhance milk production.

Meanwhile, at AgResearch’s Grasslands campus at Palmerston North, Dr Graeme Attwood, Section Manager, Ruminant Nutrition & Microbiology, is enthused by the huge potential of a new environmental microbiology approach called ‘metagenomics’.

He says ‘metagenomics promises to be the key technology that will facilitate the understanding of what goes on in a cow’s first stomach or rumen, and the relationship between forage degradation and ruminant nutrition which leads to improved milk production.

Metagenomics is an amazingly powerful new analytical tool allowing rapid progress in revealing, at a molecular level, what goes on in microbes within a cow’s stomach,” he says.

“It allows us to examine all the different micro-organisms in the rumen at the same time, and to screen their DNA for enzymes involved in the digestion of grass or supplementary feed, like silage. Previously scientists were limited to working on the 10% of microbes that were culturable from the rumen, but this powerful new analytical tool has radically improved this situation.

“We can now isolate the key enzymes in this digestive process and, based on this information, supply enzyme additives to supplementary feeds that enhance feed digestion and improve milk production.”

Dr Attwood and his team are making good progress, having identified a range of rumen bacterial enzymes and are characterising their activities for development as future enhancers of forage digestion in ruminant animals.

Another study aimed at improving milk and meat production at AgResearch’s Palmerston North facility is the innovative use of symbiotic fungi (endophytes) living in plants to enhance the digestion of cows. Fungi are already known to have positive impacts on forage and grass production.

Dr Milan Gagic, Scientist with the Forage Biotechnology Section, is working on modifying endophytes to deliver additional highly active enzymes to cows when they graze. These enzymes may speed up the rate of digestion or degradation of forage in a cow’s stomach.

The advantage of this approach lies in the fact that modified fungal endophytes do not propagate via grass pollen which minimises any impact on other grass varieties.

“The goal is to increase the digestion rate of grass and other forage which in turn may increase milk and meat production,” says Dr Gagic.

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