Question

Which type of leukocytes (WBCs) is present in higher percentage in cattle?

• A. Neutrophils
• B. Eosinophils
• C. Monocytes
• D. Lymphocytes

Hint:

Remember this distinction: Carnivores, horses, and humans are "neutrophil-dominant" species.
Ruminants (cattle, sheep, goats) and pigs are "lymphocyte-dominant" species.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Leukocytes (white blood cells) are divided into granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).
The normal proportions of these cells in a healthy animal's blood (the differential leukocyte count) vary significantly between species.

Step 2: Detailed Explanation:
In monogastric mammals like humans, dogs, and cats, neutrophils are the most abundant white blood cell type, making up about \(60\%\) to \(70\%\) of total circulating leukocytes.
However, ruminants (including cattle, sheep, and goats) have a different leukocyte profile.
In healthy cattle, lymphocytes are the most numerous leukocytes, typically representing \(50\%\) to \(70\%\) of the total white blood cell count.
Neutrophils are the second most common, comprising only about \(20\%\) to \(35\%\) of the count in healthy adult cattle.
Eosinophils (\(2\%\) to \(8\%\)) and monocytes (\(2\%\) to \(6\%\)) are present in much lower percentages.
This unique high-lymphocyte ratio is normal for ruminants and should be considered when interpreting veterinary blood reports.

Step 3: Final Answer:
The leukocyte present in the highest percentage in cattle is Lymphocytes.