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Year 2018 - Volume 38, Number 4
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Comparative study of distinct techniques to determine differential leukocyte counts in milk, 38(4):773-778
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ABSTRACT.- Takano P.V., Blagitz M.G., Mira C.S., Batista C.F., Della Libera A.M.M.P. & Souza F.N. 2018. [Comparative study of distinct techniques to determine differential leukocyte counts in milk.] Estudo comparativo das diferentes técnicas empregadas na contagem diferencial de leucócitos no leite. Pesquisa Veterinária Brasileira 38(4):773-778. Departamento de Clínica Médica, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Avenida Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, São Paulo, SP 05508‑270, Brazil. E-mail: paulo.takano@usp.br
Milk somatic cell count (SCC) is the basis of mastitis and milk quality control programs, however it not differentiate the distinct leukocyte populations which in turn can improve the diagnosis of mastitis. Thus, the present study aimed to evaluate different techniques used to measure the distinct leukocyte populations in milk in attempt to improve the diagnosis of mastitis. Here, milk samples from 31 dairy cows (124 quarter milk samples) were used. The differential leukocytes count was determined by cytocentrifugation, direct microscopy smears, and monoclonal antibodies by flow cytometry. The automatic SCC was also performed. The results showed a positive and significant correlation between the proportion of polymorphonuclear leukocytes determined by all techniques and automatic cell count; although a discrete higher correlation between flow cytometry and automatic SCC was found. Furthermore, the present study reinforces the idea that macrophages were the predominant cell type in mammary gland with low SCC. The proportion of each leukocyte population differ among techniques, probably due to the subjectivity of the examiner in the evaluation of the differential leukocyte counts by cytocentrifugation and direct microscopy smears, which emphasize that flow cytometry can be a useful and feasible tool in the diagnosis and control of mastitis. |
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