California Mastitis Test (CMT)

Introduction

Purpose: Detect and analyze mastitis in dairy cows.
Importance: Early detection and treatment can help maintain cow health and milk production.

Inflammation of the cow's udder due to infection in mammary tissue, usually caused by bacteria.
Signs:
- Clumpy milk
- Fever
- Red or swollen udder
- Decreased food intake
- Dehydration
- Severe cases: death

Obtain a CMT testing kit from a farm supply store.
- Components: CMT paddle, CMT solution
Prepare the CMT solution as per package instructions.
Put on latex gloves.
Clean the cow's udder using a paper towel to remove dirt and manure.
Squirt several streams of milk from each quarter to ensure fresh milk.

Stand behind the cow and position the CMT paddle between the cow's rear legs under her udder.
Collect milk samples:
- Left front teat into left front paddle cup
- Right front teat into right front paddle cup
- Left rear teat into left rear paddle cup
- Right rear teat into right rear paddle cup
Ensure each cup has equal amounts of milk by tilting the paddle.
Add an equal amount of diluted CMT solution to each cup.
Gently swirl the paddle to mix the contents.

Read the test within ~10 seconds.
Visual scoring:
- Negative (N): Mixture remains liquid, no thickening.
- Trace (T): Slight thickening that disappears with continued rotation.
- Positive (1, 2, 3): Gel-like formation; thicker the gel, the more severe the infection.
- Strong Positive (3): Gel forms with an elevated surface; remains raised.

Negative (N): No infection.
Trace (T): Possible infection; if one or two quarters read Trace, cow is okay. If all four quarters read Trace, cow is infected.
Positive (1, 2, 3): Increasing levels of infection severity.
Higher Somatic Cell Count (SCC) correlates with more severe infection.