Farmers warned about the dangers of rumen acidosis in cattle

Rumen acidosis occurs when the pH of the rumen becomes acidic. It can result in a fall in production and, in severe cases, can lead to abscesses on the liver or even death.

Jill Hunter, Beef and Sheep Nutritionist for animal nutrition experts Harbro, said extra attention should be given to reduce the risks of rumen acidosis, which can be difficult to spot.

“Most commonly, acidosis is subtle and not obvious at first,” said Jill. “The primary way to judge this is on dung consistency, which tends to be less solid the more severe the acidosis. The knock-on effect of these symptoms is a loss of production. For dairy cows, this is a loss of milk production; for growing or finishing animals, it is a loss of daily live-weight gain or poor feed conversion efficiency.

“Using high lactic acid silage, feeding high levels of cereals, and new season grain are all risk factors for acidosis. This could be seasonal, such as the switch to freshly harvested grain or when they switch from growing to finishing rations.

“Prevention is always better than the cure. We know ruminants evolved to graze hills and long-stemmy forages, not to stand in a shed and eat ad-lib cereal. It is about returning to basics and ensuring the rumen environment is right, so animals can really get the most out of what we feed them.”

Jill said farmers could mitigate the acidosis risk by altering some management practices to ensure a smooth transition for the cattle when the weather turns, stock is being housed and winter rations formulated.

Ensuring the silage’s chop length is correct and the structural fibre in rations can help, Jill said.

She advises transitioning to a finishing ration should last two to three weeks; any shorter, the risk of acidosis significantly increases.

Harbro has been conducting trials using its unique rumen buffer Alkacid to optimise rumen health on its Nucleus beef research farm in North East Scotland.

It is one of a pair of farms run by Harbro to conduct practical research, providing information to aid its advice to farmers. The other farm focuses on dairy cow research.

“Science is at the heart of our research and development programme, which is why we have close links with Glasgow Vet School,” Jill said.

“The Nucleus research farms aim to impart commercial reality into our research work; a great balance between science and farming reality. They are set up to replicate a finishing unit typical of many customers, meaning our findings are highly applicable when we discuss them with farmers.”

For the Alkacid trial, cattle were a typical mix of continental and native breeds, bought from auction markets throughout Scotland.

Once they arrived on the farm, cattle were fed Harbro Beefstock nuts as a transition feed.

This is gradually phased out and replaced with ad-lib barley, which has been processed using one of Harbro Super Bruiser machines.

The cattle were divided into four pens, with two receiving Alkacid with their feed ration. This provided two replicates in the trial and a more robust dataset. They were finished and sent to the processor within 100 days of arriving at the farm.

“We were astonished by the results,” Jill added. ‘The cattle fed Alkacid in their rations gained, on average, 350g per head per day more throughout the transition period than those that did not. This gain is attributed to the cattle transitioning better, which led to improved rumen health and utilisation of their ration.

“By transitioning and finishing quicker using Alkacid, the cattle are on-farm for fewer days. This leads to an increase in profitability and a decrease in the carbon footprint. If a farmer can get cattle off their farm quicker, they can increase their business throughput by finishing more cattle in a year.

“When combined with thorough herd management, adding Alkacid to a feed ration is an easy choice when looking at our results.”