Question

What should be administered to calf in the absence of dam's colostrum in order to develop passive immunity?

• A. Dam's serum - intravenously
• B. Dam's blood - intramuscularly
• C. Dam's milk - orally
• D. Dam's skimmed milk - orally

Hint:

A calf's small intestine can absorb large immunoglobulin molecules for only about the first \(24\) hours of life. After this window, antibodies must be administered intravenously to enter the bloodstream.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Calves are born without protective antibodies (immunoglobulins) in their blood because the maternal antibodies cannot cross the complex ruminant placenta.
They rely on the passive transfer of immunity through the consumption of antibody-rich colostrum shortly after birth.

Step 2: Detailed Explanation:
If colostrum is unavailable (for example, due to maternal death or severe mastitis), the calf is highly vulnerable to systemic infections.
To establish passive immunity in a colostrum-deprived calf, administering the dam's serum intravenously is the most effective clinical method.
The dam's serum contains a high concentration of immunoglobulins that provide immediate, direct systemic protection.
Let us compare this with other options:
- Intramuscular injection of whole blood is sometimes used in the field, but it can cause tissue reactions and absorption is much slower and less efficient.
- Regular milk or skimmed milk given orally does not contain the high level of immunoglobulins needed to build systemic immunity.
Therefore, intravenous administration of dam's serum is the preferred option.

Step 3: Final Answer:
The correct treatment is Dam's serum - intravenously.