Michael Metzger, Michigan State University Extension Educator
(Previously published on MSU Extension, Sheep & Goat: January 3, 2019)
Mastitis is an important disease of sheep and goats because it decreases the amount and quality of the milk produced by a dairy animal and reduces weight gain in lambs and meat kids. It can also affect the animals well-being. Mastitis is an inflammation of udder.Physical injury, stress, or bacteria can cause mastitis. There are several bacteria which are known to cause mastitis in sheep and goats including Streptococcus sp., Staphylococcus sp., Pasteurella sp., and coliforms, such as E. coli. The exact type of bacteria that is causing the mastitis can only be determined by laboratory analysis. Mastitis can either be clinical or subclinical. Clots or serum in the milk are signs of clinical mastitis. In addition the udder may become swollen, hot and/or tender to the touch. Subclinical mastitis is only detectable using a test such as the California Mastitis Test(CMT) or counting inflammatory cells in the milk or culturing milk in the laboratory.
When bacteria enters the udder, a mastitis infection may occur. Good udder and teat conformation can help to reduce the risk of mastitis. One way to help prevent mastitis is to keep milking and living areas clean. Preventing respiratory disease in lambs and nursing kids can also help prevent mastitis and Pasteurella hemolytica, a bacteria that causes pneumonia in lambs and kids can cause mastitis. Also post dipping teats after milking can greatly reduce the risk of mastitis in milking does and ewes. Treatment of mastitis is generally done with the use of either injectable or intramammary antibiotics. There are no antibiotics that are labeled for use in sheep or goats for the treatment of mastitis. Therefore all treatment of mastitis for sheep and goats is considered extra-label and must done on the advice and under the supervision of a veterinarian. Extra-label is the use of any drug that is used for something that is not specifically listed on the label and is only permitted under the written orders of a veterinarian. Does and ewes with clinical mastitis are can be very ill and often require other supportive care. The use of intramammary dry off treatment can help with treatment of mastitis during the dry period but must be done under the direction of a veterinarian as there are no dry treatment antibiotics labeled for sheep and goats. Michigan State University Extension reminds producers to follow drug withdrawal intervals to prevent contaminated meat and/or milk from entering the food chain.
Mastitis can cause decreased production in sheep and goats, with the majority of the mastitis being subclinical. All treatment of mastitis in small ruminants is extra-label, and therefore requires a veterinary client patient relationship. Clean housing and milking practices are key to the prevention of mastitis in small ruminants.