Diarrhea in young calves remains the industry’s leading cause of morbidity (sickness) and mortality (death). In the National Animal Health Monitoring System’s (NAHMS) Dairy 2007 survey, scours, diarrhea and other digestive problems accounted for more than half (56.5%) of all preweaned heifer deaths.

University of Kentucky Extension dairy veterinarian, Michelle Arnold, said recent research has revealed better methods to assess and treat calves with diarrhea. More also has been learned about choosing the best oral electrolyte solution to restore hydration; correct acid-base electrolyte levels in the blood; and provide nutritional support for scouring calves.

Deciding whether to give calves oral or intravenous fluid therapy can be a critical call. Arnold advised the choice depends on two critical factors:

  1. If the severity of dehydration is more than 8%; and/or
  2. The severity of metabolic acidosis or low pH of the blood.

Dehydration scoring can be performed by observing the degree to which eyes are sunken, along with the “skin-tent” test. Metabolic acidosis is not as easily determined, but Arnold said can be assessed by evaluating (a) the ability to stand; and (b) the ability to suck. “In general, a standing calf with a strong to moderate suckle reflex or that demonstrates a ‘chewing action’ should safely tolerate oral fluids,” she said.

Weaker calves should be giving intravenous fluids, as they are likely to have poor gut motility. This could cause oral electrolytes to pool in the rumen, resulting in bloat and rumen acidosis.

Arnold advised that oral electrolytes should be fed as extra support in between regular milk feedings, but not in place of milk or milk replacer.

Read more of Arnold’s insights on scours and electrolyte therapy here.