O impacto da Haematobia irritans na prevalência da mastite subclínica em rebanhos leiteiros
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Data
2025-03-12
Autores
Serafim Júnior, Alclecir Bitencourt
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Universidade Federal do Espírito Santo
Resumo
The present study aimed to evaluate the ability of the horn fly (Haematobia irritans) to carry bacterial agents causing subclinical mastitis in cattle, relating the microbiota present on the surface of these insects to the identification of bacteria in milk samples and swabs from the teat surfaces of cows diagnosed with subclinical mastitis. The study was conducted on two dairy farms in the municipality of Alegre, Espírito Santo, Brazil, where technical visits were carried out to assess sanitary conditions and milk production management.The identification of cows with subclinical mastitis was performed using the California Mastitis Test (CMT), and milk and teat surface swab samples were collected from positive animals. Horn flies were captured in the milking area, near the animals. The samples were subjected to bacteriological cultures on MacConkey Agar, Brain Heart Infusion (BHI) Agar, and Sabouraud Agar, and the isolated colonies were characterized based on colony morphology, Gram staining, and biochemical tests for catalase and coagulase. The results indicated that Staphylococcus aureus was the main etiological agent isolated, being present in most milk and teat swab samples from cows with subclinical mastitis. Additionally, microbiological analysis of the flies revealed the presence of S. aureus, Gram-positive bacilli, and Gram-negative bacilli, demonstrating that these insects can act as mechanical vectors for pathogen transmission in the milking environment. The multivariate statistical analysis (PCA) revealed a strong association between the fly microbiota and the presence of S. aureus in milk and teat samples, especially in Farm 1, where the pathogen was predominant. In Farm 2, Streptococcus spp. was identified more frequently, suggesting a closer relationship between milking hygiene and the presence of these microorganisms. Based on these findings, it is concluded that the horn fly acts as a vector for bacterial agents associated with subclinical mastitis in cattle, making it an epidemiologically relevant factor in the dairy production chain. Thus, effective control of this ectoparasite is essential to reduce the spread of microorganisms in the milking environment and mitigate the impact of subclinical mastitis on dairy productivity. Furthermore, continuous monitoring of the isolated bacteria can support more effective sanitary management strategies on dairy farms, minimizing economic losses and improving milk quality.
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Controle de vetores , Microbiologia veterinária , Produção leiteira