Clinical Aspects of Ruminal Acidosis in Dairy Cattle

Abstract

Acute and subacute ruminal acidosis are well recognized as important diseases in beef feedlots.^6,14,32,37 Acute ruminal acidosis has been long recognized in dairy cattle, although deaths due to acute ruminal acidosis are apparently less frequent in dairy cattle than in beef feedlot cattle. ³⁵ Only recently has subacute ruminal acidosis (SARA) been described for dairy cattle.²⁶

Although dairy cattle are typically fed diets higher in forage and fiber compared to beef feedlot cattle, total consumption of rapidly fermentable (non-fiber) carbohydrates is similar between these two livestock classes because lactating dairy cows have very high feed intakes. This principle is illustrated by the data presented in Table 1. Ruminal pH values measured by continuous data acquisition in feedlot steers and lactating dairy cattle were similar when the cattle consumed similar total amounts of non-fiber carbohydrates. The prevalence of SARA in dairy herds is probably about the same as it is in beef feedlots.

The objectives of this paper are to review the pathophysiology, clinical signs, diagnostic methods and prevention of ruminal acidosis in dairy herds. The subacute form of ruminal acidosis will be emphasized.