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Detection of ovine intramammary infection with the California mastitis test
Abstract:
The overall sensitivity of the California mastitis test (CMT) for detecting intramammary infection (the likelihood of a positive CMT score in the presence of intramammary infection) was 69.3%. The specificity of the CMT (likelihood of a negative test in the absence of intramammary infection) was 76.5%. When only infections by major ovine mastitis pathogens were considered, the sensitivity increased to 100% and the specificity decreased to 71.1%. Bacterial cultural examination and CMT scores were recorded for 526 samples of milk obtained from 106 brood ewes. Positive CMT scores were recorded for all samples from udder halves infected with major ovine mastitis pathogens (coagulase-positive staphylococci, Escherichia coli, and Pasteurella haemolytica). The CMT scores for samples from udder halves infected with coagulase-negative staphylococci were variable.
Insights
The California mastitis test (CMT) detects intramammary infections in ewes with 69.3% sensitivity and 76.5% specificity. It shows 100% sensitivity for major pathogens but variable results for minor ones.
Area of Science:
- Veterinary Medicine
- Animal Science
- Microbiology
Background:
- Intramammary infection (IMI) is a significant concern in sheep farming.
- Accurate diagnostics are crucial for managing ovine mastitis.
- The California mastitis test (CMT) is a common diagnostic tool.
Purpose of the Study:
- To evaluate the diagnostic accuracy of the California mastitis test (CMT) for detecting intramammary infection in brood ewes.
- To assess CMT performance against major and minor ovine mastitis pathogens.
Main Methods:
- Collected 526 milk samples from 106 brood ewes.
- Performed bacterial cultural examination for pathogen identification.
- Recorded California mastitis test (CMT) scores for each sample.
Main Results:
- Overall CMT sensitivity was 69.3% and specificity was 76.5%.
- Sensitivity increased to 100% for major ovine mastitis pathogens (Staphylococci, E. coli, P. haemolytica).
- Specificity decreased to 71.1% for major pathogens; CMT results were variable for coagulase-negative staphylococci.
Conclusions:
- CMT is highly sensitive for detecting major ovine mastitis pathogens.
- CMT performance varies with specific bacterial agents, particularly coagulase-negative staphylococci.
- CMT can be a useful screening tool for ovine mastitis, but confirmatory testing is recommended.