If dairy producers could see inside their cows’ rumen, they’d notice the environment can fluctuate throughout the day. In fact, it fluctuates quite frequently and for long periods of time. The time spent below a pH of 6.0 is known as Sub Acute Rumen Acidosis (SARA).1

While individual cows do not always show immediate or overt signs, SARA is always present. In fact, costs from SARA are estimated at $1.12 per cow daily,2,3 making it recognized as the most important nutritional issue of dairy cattle on a herd basis,2,4 says Anthony Hall, MSc MSB, PAS, Technical Services, Ruminant, with Lallemand Animal Nutrition.

“This period of time is important because a pH of less than 6 has negative effects on ruminal cellulolytic bacterial activity and fiber digestion,”1 Hall says. “In fact, studies have shown that the rumen environment can be exposed to SARA for up to 11.8 hours daily that’s almost a half a day with impaired digestion.”5

Even cattle fed total mixed rations (TMRs) and in-feed dietary buffers like sodium bicarbonate are at risk depending on an individual cow’s meal pattern, he notes.2,4

“A cow’s rumen pH will vary throughout the day, which can lead to changes in the rumen microbiota and damage the rumen wall,”2,4 Hall says. “This can mean losses in milk production and feed efficiency.2,4 Plus, once cows experience SARA, they can become more susceptible to it if challenged again.”5

SARA is recognized as a herd syndrome, but the risk is not the same for all cows. There are a number of factors that will predispose fresh cows, early-lactation, high-yielding and mid-lactation cows to SARA in any herd. Probiotic feed additives that improve rumen function and increase fiber digestion — like Levucell® SC — can help maximize rumen function in all life stages of dairy cattle.

“Optimizing rumen function can help the modern dairy cow stay ahead of SARA,” Hall notes. “The benefits to producers can add up to more than just peanuts.”


1 Russell, J. B. and D. B. Wilson. 1996. Why are ruminal cellulolytic bacteria unable to digest cellulose at low pH? J. Dairy Sci. 79: 1503-1509.

2 Enemark, J.M.D. 2008. The monitoring, prevention and treatment of sub-acute ruminal acidosis: A review. The Veterinary Journal 176: 32-43.

3 Kleen J. L. and C. Cannizzo. 2012. Incidence prevalence and impact of SARA in dairy herds. Anim. Feed Sci. Technol. 172: 4-8.

4 Oetzel, G. R. 2007. Sub acute ruminal acidosis in dairy herds, physiology, pathophysiology, milk fat depression and nutrition management. AABP, 40th Annual Conference, Vancouver B.C.

5 Beauchemin, K. and G. Penner 2009. New developments in understanding ruminal acidosis in dairy cows. Tri-State Dairy Nutrition Conference. April.

Source: Lallemand News Release