DEVELOPMENT OF A DIAGNOSTIC PROTOCOL FOR MASTITIS IN GOATS

Mastitis is an inflammation of the mammary gland that can lead to alterations in milk produced and composition. Therefore mastitis represents an important problem for animal welfare and public health (1). A wide range of infectious agents is known to cause mastitis. Contagious pathogens such as Staphylococcus aureus and Streptococcus agalactiae are transmitted among animals. Environmental pathogens such as Streptococcus uberis and Streptococcus dysgalactiae are opportunistic invaders of the gland (2). Among viral agents Small ruminant lentiviruses (SRLV) can cause subclinical mastitis (3). Aim of this research was to develop a diagnostic protocol for goat’s mastitis correlating the pathologic findings with the isolated microorganisms. 25 udders with macroscopically suspected mastitis were collected in a small slaughterhouse in northern Italy from regularly slaughtered dairy goats and sent to the Department of Veterinary Science, Torino University. Anamnestic data about the animals (age, breed, characteristics of the farm) were also reported. After gross examination, 2 samples were removed: one, ïˇn?xed in 10 neutral buffered formalin for histological investigations and the other one, frozen at -20ÂC as tissue bank. The remaining tissue was sent to the Istituto Zooprofilattico Sperimentale of Torino to perform bacteriological, virological (PCR for ecthyma and SRLV) and mycological investigations. Antibiogram and research of inhibitory substances were also made. According to the literature, the pathological lesions and the bacteria isolated revealed a high prevalence of suppurative-chronic infections. In fact histologically most of the udders (80%) showed chronic mastitis characterized by mixed or suppurative infiltrates. This result was supported by bacterial isolates reporting in particular pyogenic agents. Nevertheless the histological findings were difficult to correlate with the microbiological data because often co-infection of several microbial species were isolated in the same udder( 84%). Staphylococcus spp.(37%) - especially S. caprae, S. xylosus and S. aureus- and Streptococcus spp.(9%) -especially S. agalactiae and S. uberis- were the most frequently isolated bacteria. Mycological survey was positive only in one udder (Aspergillus spp.) probably as a contaminant. 20 udders were positive for SRLV (genotype A), only one sample was PCR positive for the contagious ecthyma virus. 22 samples were negative for the research of inhibitors. No particular antimicrobial resistances were observed to routine texted antibiotics. This diagnostic protocol was easy to perform and relatively quickly. It provides a large number of data and it is also applicable to the ovine species whose agents of mastitis are similar. In the absence of an histological classification of small ruminant mastitis, this protocol can be useful to define a specific classification in these species. Moreover it can represents a useful epidemiological tool. In particular antibiotic resistance data can be used to select a correct therapy in the farm. To correlate the pathologic findings with the isolated microorganisms a greater number of samples have to be carefully investigated.