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

Author(s):Show less -

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

• Document type: Journal article
• Source: CIENTIA AGRICOL; v. 80, p. 12-pg., 2023-01-01.

Abstract

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)

• FAPESP's process: 14/23189-4 - Intramammary infections by Staphylococcus aureus: crosstalk between mammary epithelial cells and peripheral blood mononuclear cells, and how it governs immunity in the mammary gland of dairy cows
• Grantee: Fernando Nogueira de Souza
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 09/50672-0 - Functional evaluation of blood and milk leukocytes of cows naturally infected by bovine leukosis virus
• Grantee: Alice Maria Melville Paiva Della Libera
• Support Opportunities: Regular Research Grants