Question

The dose rate of Amprolium for treatment of coccidiosis in calves is
A. 10 mg/kg body weight for 5 days
B. 65 mg/kg body weight once
C. 30 mg/kg body weight for 14 days
D. 100 mg/kg body weight once
Choose the correct answer from the options given below:

• A. A and D only
• B. C and D only
• C. A and C only
• D. A and B only

Hint:

Amprolium is a thiamine antagonist. Because coccidia cannot synthesize their own thiamine, they are highly sensitive to this drug, which must be administered daily over several days to cover the active replicative phases of their life cycle.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Coccidiosis in calves, caused primarily by Eimeria bovis and Eimeria zuernii, is a significant cause of diarrhea, dysentery, and poor growth.
Amprolium is a thiamine analogue that competitively inhibits thiamine uptake by coccidia, arresting their development during the first-generation schizont stage.
Detailed Explanation:
The dosage and administration of Amprolium can vary depending on whether the goal is treatment of active clinical disease or prevention/control during an outbreak:
- A. 10 mg/kg body weight for 5 days: This is the standard, widely accepted therapeutic dosage for treating active clinical coccidiosis in calves. It is administered daily, either in drinking water, milk replacer, or as a drench.
- C. 30 mg/kg body weight for 14 days: This higher dosage range (or extended regimens up to 10--20 mg/kg for 21 days, or higher therapeutic doses in feed under certain severe conditions) is utilized as an alternative preventive or herd-treatment strategy during high-exposure risk periods to control the outbreak.
- Single-dose regimens (such as 65 mg/kg once or 100 mg/kg once) are not effective for coccidiosis because the life cycle of Eimeria requires sustained therapeutic blood levels over several days to inhibit the multiplying asexual stages.
Thus, the correct established regimens for Amprolium use are represented by options A and C.

Step 2: Final Answer:
The correct answer is A and C only, which is Option (C).