Feeding unsaturated fats could help raise milk yield

Dairy producers looking to bolster milk sales handicapped on many farms by the feeding of last year’s high fibre forage – leading to unusually high butterfats at the expense of yield – are being encouraged to use unsaturated fat in rations for the remainder of winter.

Nick Johns, technical director of north-west-based HST Feeds, is already using the technique, with a dozen dairy clients facing this scenario. “This is a short-term fix allowing some producers to increase milk sales and revenue through to turnout at a time when there’s little prospect of quota restriction.

“We’re in the unusual situation of having high fibre winter forages with typical NDF levels of 52-54% against a norm of 48-50%. This increases production of acetate (acetic acid) in the rumen and often leads to lower yields and higher butterfats. Some producers have levels of up to 4.6% while contracts often stipulate a base threshold of 3.5-3.7%.”

Soya oil

Producers who can afford to lose 0.2-0.3% butterfat without breaching contracts could consider using unsaturated fat such as soya oil in rations, says Mr Johns. “Rumen bugs channel unsaturated fat down a particular metabolic pathway where, on reaching the udder tissue, it reduces fat synthesis. This leaves more energy for lactose production that stimulates milk yield.”

Inclusion rates of up to 5% in a ration’s concentrate, to supply 0.25-0.45kg a day, will be sufficient to reduce butterfat and lift yield, he suggests. “If you just tipped soya oil into a feeder wagon it would coat the silage and reduce intake, then both yield and fat would go down.”

Incorporating it into a meal so the fat molecules are bound to feed particles – possibly replacing some or all of the saturated fat energy sources – will lower butterfat and raise the milk volume.


  • High fibre diet lifts butterfat

  • Unsaturated fat partitions energy towards more milk

  • Not suitable for all herds

“At £420/t soya oil costs about £4 per 1% inclusion. For one of our clients feeding 2t meal to a herd of 225 cows it increased the ration cost by just £15 a day. Even an average increase in yield of two litres a cow a day gave an extra 450 litres in the tank worth £85.50 at 19p/litre – a clear margin of £70 a day,” he explains.

Knutsford-based producer Dale Whalley of Tabley Hill Farm, reckons replacing saturated fat in a meal blend with 5% soya oil in two carefully managed stages has already made a significant impact on his 250-cow herd’s bottom line in recent weeks.

“Yields have slowly risen by four litres a cow a day compared to January 2006, butterfat has fallen to 4.1% and cows look healthier, too,” he explains.

“We’re now putting an extra 1000 litres a day into the tank for a modest investment it’s a revolution for us albeit we were a little unsure at first,” says Mr Whalley.


But this won’t suit everyone, warns Mr Johns. “High yielding herds achieving good yields or those producers close to contract thresholds for butterfat may not benefit from the switch. Likewise, it’s only a technique that can be used while high fibre winter forages are being fed.

“Turnout on to fresh spring grass which contains a naturally high level of unsaturated fat would see both butterfat and yields hit where additional unsaturated fats continued to be included in rations,” warns Mr Johns.

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