The prevention and control of mastitis in sheep

Mastitis is a major a problem in dairy farming, being a threat to animal health and welfare, production efficiency, and product quality. Mastitis is the result of contagious pathogens such as Streptococcus agalactiae, Mycoplasma spp. and Staphylococcus aureus, entering the mammary gland via teat canal, establishing an intramammary infection (IMI) and resulting in an inflammatory reaction. The disease can be in a clinical or subclinical form. 

In the subclinical form; milk production decreases, bacteria are present in the secretion, and composition is altered. Transmission of contagious mastitis pathogens mainly occurs during milking. Bedding is also very closely related to the bacteria exposure of the sheep since teats may be in direct contact with bedding materials which are a  primary source of mastitis causing pathogens. 

Tests have to be used to detect the presence of intra-mammary infections (IMI) either directly (culturing of the causative bacterium) of indirectly (by showing inflammatory response including an elevated somatic cell counts-SCC). 

A vaccination program is recommended to be included in the control of mastitis together with hygiene methods in sheep flocks. Mastitis treatment may contribute to reduced transmission of infection, but antimicrobial treatment of mastitis is not always successful. When treatment fails, removal of the infected animals from the flock, to prevent contagious transmission, may be necessary. 

The implementation of biosecurity measures such as: 

1. good husbandry and milking practice with regular maintenance of the milking machine, and 
2. use of post-milking teat disinfection  

can prevent introduction and transmission of mastitis in dairy ruminants, and consequently, reduce antibiotics usage.