Low Ruminal pH Could Be Dragging Down Your Herd Health

When a cow's ruminal pH dips below 5.8, it starts to drag her overall health down too. The cascade of events ultimately leaves producers with increased treatment expenses and decreased overall production.

"For the modern dairy cow, it's common to take between six to 10 meals in a 24-hour period," says Anthony Hall, MSc MSB, PAS, Technical Services, Ruminant, with Lallemand Animal Nutrition. "This naturally leads to fluctuating pH throughout the day. It's been documented that lactating cows can spend up to 11.8 hours with a rumen pH below 5.8, which can mean nearly half a day of impaired digestion. A cow is simply not going to be in the best rumen health under these circumstances, and lowered health can damage the overall productivity of the farm."

The period when the cow's rumen pH is below 5.8 for more than three hours at a time is known as Sub Acute Ruminal Acidosis (SARA).1 Recurrent bouts of SARA can lead to erosion of the rumen wall, which allows bacteria in the blood stream. It can lead to liver abscesses, peritonitis or even damage to the heart, lungs or joints. Recurrent SARA also can cause long-term hoof-related problems that persist well after rumen pH balance is restored.

"SARA can have negative consequences to herd productivity," Hall notes. "It's important to reduce a herd's risk of SARA so you're heading the problem off, rather than trying to fix it later."

All cattle are at risk for SARA, but the most commonly affected groups are fresh cows and high-yielding cows. Affected animals will eat more sporadically or reduce their feed consumption. Other signs of SARA include: decreased efficiency of milk production, reduced fat test, a higher incidence of milk component inversions, poor body condition score, unexplained diarrhea and episodes of laminitis.

Proper feed bunk management, ration formulation and delivery can help protect the herd from experiencing SARA, Hall notes.