Colonization of Extramammary Sites with Mastitis-Associated Strains in Dairy Goats

(), a major mastitis pathogen in dairy goats, is classified as a contagious pathogen. Although previous research has shown that extramammary body sites can be colonized with , it is unknown whether these sites are reservoirs for intramammary infections. The aim of this research was to determine whether extramammary sites can be colonized with mastitis-associated strains in dairy goats. Milk samples were collected from 207 primiparous goats and from 120 of these goats, extramammary site samples (hock, groin, nares, vulva and udder) were collected from a large commercial dairy goat herd in the Netherlands during four sampling visits. Extramammary site swabs and milk samples were (selectively) cultured and isolates were genotyped. The prevalence of colonization of the extramammary sites at goat level was 51.7% and the prevalence of intramammary infections was 7.2%. The nares were colonized most frequently (45%), while the groin area was colonized the least (2.5%). Six genotypes were identified in this herd and there was no significant difference in the distribution of genotypes between the milk or the extramammary sites ( = 0.141). Both in the extramammary sites and in the milk, genotypes t544 (82.3% and 53.3%) and t1236 (22.6% and 33.3%) were the dominant genotypes. These results show that in goats, extramammary sites, particularly the nares, are frequently colonized with mastitis-associated strains. Extramammary sites may, thus, be a source of intramammary infections that are not targeted by the intervention measures aimed at preventing transmission from infected udder glands.