Deeper exploration of inflammatory cell populations in milk to monitor udder health in dairy cows

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de Souza, Carolina Menezes Suassuna ; Blagitz, Maiara Garcia ; Souza, Fernando Nogueira ; Batista, Camila Freitas ; Lima, Daniel Magalhaes ; Alves, Alexandre Jose ; Heinemann, Marcos Bryan ; Sanchez, Eduardo Milton Ramos ; Torres, Hugo Frias ; Fernandes, Artur Cezar de Carvalho ; Libera, Alice Maria Melville Paiva Della

• Tipo de documento: Artigo Científico
• Fonte: CIENTIA AGRICOL; v. 80, p. 12-pg., 2023-01-01.

Resumo

The present study explored the predictive values of milk leukocyte differentials (MLD) as a basis for improving the diagnosis of intramammary infections (IMIs) and subclinical mastitis. Quarter milk samples were collected for bacteriological analysis, quarter somatic cell count (qSCC), and MLD. The MLD were assessed using the cytospin technique, direct microscopic smears, and flow cytometry. The predictive values of each single leukocyte population and useful potential indices that could better reflect immune complexity were also calculated. Changes in the percentage of any leukocyte alone failed to substantially improve the predictive value of qSCC in diagnosing IMIs. Although certain parameters increased the area under the receiver operating characteristic curve (ROC curve) as a result of increased specificity values, a slight reduction in sensitivity was observed. The so-called CD8 complex was a unique parameter which improved both the sensitivity (78.79 %) and the specificity (80.77 %) in IMI diagnosis, resulting in the highest area under the ROC curve (0.87). To diagnose subclinical mastitis, the percentage of macrophages and the sum of the percentage PMNLs and T CD8+ cells divided by the percentage of macrophages showed the highest predictive values (sensitivity = 79.63, specificity = 73.68, and area under the ROC curve = 0.83) in the differentiation of the inflammatory condition status of cows. In conclusion, this study provides further insights into using T CD8+ lymphocytes in diagnosing bovine IMIs, combined with PMNLs and macrophages. The antidromic trend of macrophages vs. PMNLs and T CD8+ lymphocytes due to the increasing qSCCs was crucial to differentiating quarters under both inflammatory and non-inflammatory conditions. (AU)

• Processo FAPESP: 14/23189-4 - Interação das células epiteliais mamárias e das células mononucleares do sangue periférico na regulação da resposta imune e na infecção intramamária por Staphylococcus aureus, em bovinos
• Beneficiário: Fernando Nogueira de Souza
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 09/50672-0 - Avaliação funcional dos leucócitos sanguíneos e lácteos de vacas naturalmente infectados pelo vírus da leucose dos bovinos
• Beneficiário: Alice Maria Melville Paiva Della Libera
• Modalidade de apoio: Auxílio à Pesquisa - Regular