Diagnosing Subclinical Mastitis in Buffaloes: From SCC and CMT to Molecular Tests

Subclinical mastitis (SCM) can remain hidden because the buffalo may show no obvious udder or milk abnormalities. Diagnosis therefore depends on detecting changes that are not apparent during routine clinical examination and, when necessary, identifying the microorganisms involved. 

Start With Practical Screening 

Somatic cell count (SCC), California Mastitis Test (CMT), and similar on-farm tests can help detect changes associated with mammary inflammation. Their relatively low cost and practical use make them suitable for routine herd screening^[1]. 

SCC is particularly useful because an elevated count can indicate an inflammatory response even when clinical signs are absent. An SCC of approximately 100,000 was reported for healthy milk, while values above 200,000 were classified as indicative of SCM^[2]. 

However, SCC is not interpreted independently of the animal and herd context. Breed, age, parity and season can influence SCC, which needs to be considered when assessing results^[1]. 

What Does CMT Tell You?^[1] 

CMT provides a simple way to screen individual quarters for changes associated with increased somatic cells. This makes it useful when repeated monitoring is needed, or laboratory facilities are limited. 

Its limitation is important: A screening test can indicate inflammation but does not necessarily identify the causative microorganism. False-positive and false-negative results can also occur. When the result does not fit the clinical picture, additional investigation may therefore be required. 

When Pathogen Identification Matters 

Molecular methods can provide a more specific approach when identifying the causative organism becomes important. 

Techniques including PCR, real-time quantitative PCR (RT-qPCR), reverse-transcription PCR (RT-PCR), loop-mediated isothermal amplification (LAMP), microarray analysis and next-generation sequencing (NGS) have been used for detecting mastitis-associated microorganisms^[1]. 

These approaches can provide high sensitivity and specificity and allow more detailed identification of microorganisms than routine screening methods. 

That distinction is relevant because buffalo mastitis can involve different groups of pathogens. Staphylococcus aureus and Streptococcus agalactiae are associated with contagious transmission, while organisms such as Escherichia coli, Klebsiella pneumoniae and Streptococcus uberis are associated with environmental exposure^[1],[3],[4]. 

Matching the Test to the Clinical Question^[1] 

Not every suspected SCM case requires the same level of testing. 

For routine herd surveillance, SCC and CMT can provide practical first-line screening. When results are inconclusive, infection persists, or identification of the causative microorganism is required; laboratory-based and molecular methods can provide additional information. 

The objective is not simply to use the most advanced test available. It is to select the diagnostic approach that answers the clinical question while providing enough information to guide the next step. 

Clinical Takeaway 

SCC and CMT can reveal the inflammatory signal that routine examination may miss, while molecular methods can provide more specific information about the microorganisms involved. Using these approaches appropriately can strengthen the detection and investigation of subclinical mastitis in buffalo herds.

References:

1. Chowdhury MS, Rahman MM, Hossain H, Ghosh PK, Islam MR, Lamichhane B, Gomaa FA, Selim HM, Hossain MM, Helmy YA, El Zowalaty ME. Subclinical mastitis of buffaloes in Asia: prevalence, pathogenesis, risk factors, antimicrobial resistance, and current treatment strategies. Journal of Animal Science and Technology. 2026 Jan 31;68(1):18. https://pmc.ncbi.nlm.nih.gov/articles/PMC12923260/
2. Alhussien MN, Dang AK. Milk somatic cells, factors influencing their release, future prospects, and practical utility in dairy animals: An overview. Veterinary world. 2018 May 2;11(5):562. https://pmc.ncbi.nlm.nih.gov/articles/PMC5993762/pdf/VetWorld-11-562.pdf
3. Azevedo C, Pacheco D, Soares L, Romão R, Moitoso M, Maldonado J, Guix R, Simões J. Prevalence of contagious and environmental mastitis-causing bacteria in bulk tank milk and its relationships with milking practices of dairy cattle herds in São Miguel Island (Azores). Tropical animal health and production. 2016 Feb;48(2):451-9. https://link.springer.com/content/pdf/10.1007/s11250-015-0973-6.pdf
4. Tomanić D, Božin B, Kladar N, Stanojević J, Čabarkapa I, Stilinović N, Apić J, Božić DD, Kovačević Z. Environmental bovine mastitis pathogens: Prevalence, antimicrobial susceptibility, and sensitivity to Thymus vulgaris L., Thymus serpyllum L., and Origanum vulgare L. essential oils. Antibiotics. 2022 Aug 9;11(8):1077. https://www.mdpi.com/2079-6382/11/8/1077