DAIRY farmers could see big benefits by adding a stabilised yeast culture to their cow's diets this winter.

Trials involving the dairy herd at Askham Bryan College, near York, saw yields rise by 1.5 litres a day with butterfat up 0.5pc and protein up 0.1pc.

It resulted in an additional net profit of £82.35 per cow per lactation on yield only - £14,000 for the 170-cow herd.

Cows from the college's calving Holstein herd were introduced to Lactaid in the total mix ration, comprising grass and maize silage.

The stabilised yeast was fed at a recommended rate of 50gms per cow per day over a 64-day period.

Andrew Reilly, herd manager, said: "Within the first ten days, we recorded a yield increase of 1.5 litres per cow per day, an increment that persisted throughout the trial.

"In addition, average butterfat lifted from 3.8pc to 4.3pc and protein from 3.3pc to 3.4pc.

"Furthermore, dung consistency improved within days of introducing Lactaid and there were fewer whole maize grains to be seen."

Mr Reilly said that as soon as the official trial period was up he deliberately removed the stabilised yeast from the TMR.

"Yield dipped immediately to exact former levels," he said. "My next decision was made from a business perspective.

"Lactaid was reintroduced and now features as a permanent ingredient in the herd's diet; it's an important piece in the jigsaw, helping us to exploit yield potential and subsequent herd profitability.

"The stabilised yeast has helped to lift yield in the last 12 months by more than 1,200 litres to the current 9,959 litres herd average.

"We no longer feed sodium bicarbonate to counter acidosis, milk quality has been sustained at higher levels, and I believe the yeast helped to stabilise the diet last winter after what had been a very difficult forage making season."

Andrew Clark of Agri-Lloyd said the Askham Bryan findings reflected independent results at more than 30 different trials in America.

He said: "It was a decade of intense research where cows yielded, on average, an extra 1.5 litres per day more during the lactation over the control groups.

"In addition to the higher peak yield and a more persistent lactation curve, the cows fed Lactaid achieved a more stable rumen pH and subsequently acidosis risks were reduced, palatability increased, and overall, feed conversion was improved."

Mr Clark said when live yeast ferments, it produces metabolites - nutrients such as amino acids, peptides, enzymes, organic acids, B-vitamins and minerals - all of which are essential for feeding the rumen bacteria, rapidly increasing the total number of fibre-digesting bacteria and lactate utilising bacteria, and helping to stabilise rumen pH.

He said: "However, the rumen is an unfavourable environment for live yeasts to produce these metabolites.

"In stabilised yeasts the fermentation process has already been carried out during the manufacturing process under carefully controlled conditions, rather than in the cow's rumen, and so the highest levels of beneficial metabolites are produced and available in her diet.

"In the USA where up to 80pc of dairy herds are fed a yeast product, farmers realise the benefits of stabilised yeasts over live yeasts, to the extent they now make up to 75pc of market share."

● Farmers can find out more about feeding stabilised yeasts at an open day at Askham Bryan College, York on Thursday.