Doenças infecciosas de importância na pecuária leiteira: abordagens para metrite e mastite

Abstract

This work integrates studies on two infectious diseases of major relevance to dairy production: endometritis and mastitis. Their combined effects impair herd performance and increase the need for antimicrobial use, with implications for public health and the sustainability of production systems. In this context, the present work brings together two complementary studies, based on epidemiological and microbiological approaches, with the aim of deepening the understanding of the occurrence, risk factors, and dynamics of the main agents involved in these diseases. By combining epidemiological, laboratory, and experimental analyses, the work provides support for surveillance, diagnosis, and sanitary management in bovine production systems. In the endometritis study, microbiological and cytological investigations were conducted in cows housed in compost-bedded pack systems (312 animals from 20 farms), defining an optimal threshold of 8.3% polymorphonuclear cells (PMN) for the diagnosis of subclinical endometritis and identifying significant associations between the presence of specific bacterial genera (Prevotella spp., Enterococcus spp., and Histophilus spp.) and the inflammatory response. The physicochemical characteristics of the bedding material were not correlated with PMN levels. Taken together, the studies emphasize the polymicrobial nature of these diseases, the need for context-specific diagnostic criteria, and the importance of integrated strategies that reconcile animal health, rational antimicrobial use, and management practices. In the mastitis study, 60,863 milk samples (2009–2021) from three diagnostic laboratories were analyzed, allowing the characterization of the prevalence and spatio-temporal distribution of mastitis pathogens in southeastern Brazil. A high participation of contagious agents (notably Staphylococcus aureus and Streptococcus agalactiae), occurrence of coinfections, and the influence of rainfall patterns on the occurrence of environmental pathogens (Escherichia coli and Klebsiella spp.) were observed.