A high incidence of sub-acute rumen acidosis (SARA) in UK dairy herds is eroding farm profitability, warnsDairyCo extensions officer, Adam Clay.
“More than half of UK dairy cows are thought to be suffering from Sub-Acute Rumen Acidosis.
“Optimum rumen health is critical for feed use and dry matter intakes so it has a direct impact on milk yields and constituents,” he says.
The ideal rumen pH is about 6-6.5. “This will fluctuate throughout the day, but just two hours below pH 5.8 can result in sub-acute ruminal acidodis.
“The type of feed has a direct impact on the effectiveness of the rumen. Low energy diets can reduce nutrient absorption – this means cows won’t be able to use feed efficiently.”
Forage quality in the diet is also important as it encourages more cudding. “This stimulates saliva production – an important element in rumen buffering.”
However, excessive amounts of concentrates decrease rumen pH, reduce feed intakes and microbial production and depress butterfats.
“The ideal ration of forage to concentrate is 60:40 on a dry matter basis,” says Mr Clay.
Rations must also be well mixed to avoid selective feeding. “Cows burrowing through long fibre to get to the palatable concentrated feeds are more likely to develop SARA – it is important to balance forage chop length with the need for a unified feed.”
To help prevent acidosis, producers should spread balanced forage and concentrate feeds over the day, providing starchy feed, little and often. “Parlour concentrate feeds should also be limited to between 4-4.5kg/milking.”
Separately fed forage should be good quality and available ad-lib and salt or salt licks and adequate water should be available to encourage saliva production.