North American Veterinary Licensing Examination (NAVLE) Practice Test

Watery diarrhea is a hallmark clinical sign of Cryptosporidiosis in calves, primarily caused by the protozoan parasite Cryptosporidium parvum. This condition typically presents with diarrhea that is volume-heavy and can be accompanied by dehydration, weakness, and failure to gain weight if not managed properly. The diarrheal stools may be yellowish or greenish and have a foul odor.

In young calves, this parasite is particularly significant because it can be a major contributor to neonatal diarrhea and can lead to severe health complications if timely treatment and supportive care are not provided.

The other signs listed, although serious, are not commonly associated with Cryptosporidiosis specifically in calves. Sudden death is more aligned with acute infectious diseases or acute toxicities, severe abdominal pain may indicate gastrointestinal conditions that are not typical for Cryptosporidium infection, and persistent coughing relates more to respiratory issues, not gastrointestinal parasites. Hence, watery diarrhea is the most representative and significant clinical sign for this particular condition in calves.