Question

Cows infected with pathogens have SCC of

• A. 2 L or more
• B. 1 L or more
• C. 4 L or more
• D. 5 L or more

Hint:

Somatic Cell Count (SCC) Benchmarks:
Healthy Quarter = $< 200,000\text{ cells/mL}$ ($< 2\text{ Lakhs}$).
Mastitic Infected Quarter = $\ge 200,000\text{ cells/mL}$ ($\ge 2\text{ Lakhs / 2 L or more}$).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Subclinical mastitis thresholds: milk Somatic Cell Count (SCC) exceeding 200,000 cells/mL (2 Lakhs/mL) indicates intramammary infection (IMI) with leukocyte recruitment.
Key Formula or Approach:
\[ \text{Normal Healthy Quarter SCC} < 100,000 - 200,000\text{ cells/mL} \quad | \quad \text{Infected Quarter SCC} \ge 200,000\text{ cells/mL (}\ge 2\text{ Lakhs)} \]

Step 2: Detailed Explanation:
In dairy science and mastitis diagnostics:
- Somatic Cell Count (SCC) in milk reflects the influx of immune leukocytes (neutrophils and macrophages) migrating across the blood-milk barrier to fight bacterial infection.
- According to the International Dairy Federation (IDF) and global standards:
1. A healthy, uninfected mammary quarter has an SCC $< 100,000 - 200,000\text{ cells/mL}$ ($< 1 - 2\text{ Lakhs/mL}$).
2. An SCC of 2 Lakhs ($200,000\text{ cells/mL}$) or more is the international diagnostic threshold establishing the presence of an active Intramammary Infection (Subclinical Mastitis) caused by bacterial pathogens.

Step 3: Final Answer:
Hence, cows infected with pathogens have SCC of 2 L or more (2 Lakhs or more), matching option (A).