Streptococcus dysgalactiae – This gram positive, beta-haemolytic, coccal bacterium can be spread from cow-to-cow or acquired from the environment. Good hygiene and mastitis control programs including post-milking teat disinfection, antibiotic dry cow therapy and maintaining a clean, dry environment will reduce infections caused by this pathogen.
Streptococcus uberis – This gram-positive bacterium is the most frequent cause of mastitis in lactating cows. It can be isolated from the udder, skin, lips, and genital area of dairy cows, but infections are typically acquired from the environment. This bacterium causes mastitis during the dry period and are isolated frequently from cows with clinical mastitis during early lactation. Good hygiene and mastitis control programs including post-milking teat disinfection, antibiotic dry cow therapy and maintaining a clean, dry environment will reduce infections caused by this pathogen.
Other Streptococcus species isolated less frequently include the following:
S. acidominimus, S. alactolyticus, S. canis, S. zooepidemicus, S. equi, S. equinus (formally S. bovis), and S. parauberis.
Enterococcus species – Enterococcus species are a gram-positive cocci and lactic acid bacteria. Species include E. durans, E. faecalis, E. faecium, and E. saccharoluticus. These bacteria cause clinical and subclinical mastitis infrequently. Cows are infected from environmental contamination. Effective mastitis control procedures as mentioned above will control these mastitis-causing pathogens.