Study shows cows benefit from varied diet

Dairy farmers can improve the quality of their milk by mixing up the type of pasture their cows feed on, according to new research from Lincoln University.

The study found a varied diet could also reduce nitrates in cow urine, helping to prevent runoff into waterways.

Research supervisor Pablo Gregorini described the discovery as a “win, win, win”, which would benefit the environment, the animals, and the farmers.

“[The milk] has a better fatty acid profile, which is healthier – more Omega 3, more poly-unsaturated fats,” he said.

The study, published in the journal Animals, was carried out by former PhD student Cameron Marshall at the Lincoln University research farm.

Scientists looked at a group of ‘environmentally friendly’ cows, which carry a special genetic marker. A previous study has shown that – due to their good genes – these animals excrete as much as 28% fewer nitrates in their urine.

The team fed these animals on plantain, a fibrous herb that carries a high mineral content. The change from traditional rye grass pasture helped to reduce nitrate leaching even further, and researchers found an added benefit: the quality of the milk improved.

“It’s not all about the environment, it’s also about health,” said Pablo Gregorini, who oversaw the study.

“These cows that have a reduced environmental impact from a nitrogen point of view, they produce milk that has a chemical composition that potentially will affect human health in a positive way.”

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