New research from Penn State University shows that cows adjust their eating behavior — when given a choice — in the face of subacute ruminal acidosis.

In the study, eight lactating cows were given a choice between a long-forage-particle-size diet with slow-fermenting starch and a short-forage-particle-size diet with fast-fermenting starch. Cows were allowed to adapt to this feeding scheme and then were subjected to a rumen challenge to induce a bout of subacute ruminal acidosis (SARA), the researchers wrote in the October 2013 edition of Journal of Dairy Science.

On the day of the rumen challenge, intake of the long-forage-particle-size diet increased dramatically to 38.3 percent of total daily dry matter intake. The next day, it dropped back down to 28 percent. Then, on the second recovery day, it settled in 18.6 percent — a baseline level seen prior to the rumen challenge.

"Dairy cattle can significantly alter their TMR preference, when faced with SARA, to a diet with increased peNDF and slower starch fermentability that may help alleviate their acidotic condition," the researchers wrote. "In addition, this study showed that dairy cattle with this severity of a single bout of SARA can fully recover within 72 hours after onset."

Read the abstract.