Farmers could 'really drive milk yield and milk fat' by carefully managing a fresh cow group and target feeding high protein and amino acid diets.

That was one of the messages from Professor Bill Weiss, of Ohio State University, during his week long tour of the UK as part of the Mole Valley Farmers' 'Lifetime Dairy' roadshow, which was heldin Ayr, Nantwich, Shepton Mallet, Launceston and Carmarthen.

He told farmers that running a fresh cow group for the first 3-4 weeks of lactation could bring 'tremendous benefits'. “It’s the one group that can help health problems, help reproduction, improve production and lower feed costs,” he said, emphasising that farmers needed to ensure they had the labour and facilities to manage it.

Having this separate group encouraged intense observation of fresh calvers and health protocols to be implemented. It also created the opportunity to target feeds to this smaller group.

He said it was well worth feeding high protein diets at this time as research had shown that such an approach could lower ketosis risk and bring long-term production benefits. Professor Weiss cited research published in the Journal of Dairy Science where fresh cows were fed three different crude protein diets in the first 25 days in milk; 16%, 19% and 21%.

Cows fed the higher protein diets ate about 2kg more feed per head per day, versus the 16% crude protein diet. “High protein diets stimulate feed intakes in a fresh cows – that’s what you want,” commented Professor Weiss.

That equated to about 4kg more fat corrected milk in cows fed the 19% crude protein diet compared to the 16%. Cows fed 21% crude protein produced only slightly more milk than cows fed the 19% diet. Milk fat percentage went down, but because yield went up, milk fat yield also went up. Milk protein percentage and protein yield also increased.

Because cows were eating more, cows on the high protein diets also had lower levels of sub-clinical ketosis, despite the fact they were producing more milk.

A separate experiment, conducted by Professor Weiss in the US, found that meeting fresh cow requirements for metabolisable energy and lysine and methionine amino acids in the first 25 days in milk resulted in greater milk fat yield. This benefit also carried on for 60 days after the diet had stopped being fed.

“You pay the high price supplement for 25 days and you still get the benefit for another 60 days,” Professor Weiss said.