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Professional Version

Mastitis in Goats


Ronald J. Erskine

, DVM, PhD, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University

Reviewed/Revised May 2020 | Modified Oct 2022

The organisms that infect the udder of does are similar to those in cows. Coagulase-negative staphylococci are generally the most prevalent and can cause persistent infections that result in increased cell counts and low-grade mastitis with some recurring clinical episodes. The level of infection and incidence of mastitis due to Staphylococcus aureus tends to be low (< 5%) but can result in persistent infections that do not generally respond to therapy. Streptococcal intramammary infections can occur in both subclinical and clinical cases but are usually much less frequent than in cattle. Streptococcus agalactiae is not a common mastitis pathogen in does.

Mycoplasma infections, primarily M mycoides (large colony type) and M putrefaciens, sometimes cause serious outbreaks of mastitis in goats ( see Contagious Agalactia Contagious Agalactia ). The latter also causes septicemia, polyarthritis, pneumonia, and encephalitis, together with serious disease and mortality in suckling kids. M capricolum has also been reported to cause severe mastitis in goats and infection in kids. Does usually recover in ~4 weeks.

As with cows, gram-negative organisms cause intermittent infections that may be severe but are usually self-limiting. Trueperella (formerly Arcanobacterium) pyogenes sometimes produces multiple, nodular abscesses.

Programs for diagnosis, control, and treatment of bacterial mastitis in does are similar to those in cows Clinical Mastitis With few exceptions, mastitis occurs when microbes enter the teat via the teat canal. Almost any microbe can opportunistically invade the teat canal and cause mastitis. However, most infections... read more Clinical Mastitis . However, monitoring subclinical mastitis with somatic cell counts (SCCs) in does is difficult because of poor discrimination between infected and noninfected animals, especially in the later stages of lactation. This is partially because a of a higher proportion of epithelial cells in caprine milk than in bovine milk. As lactation progresses, shedding of epithelial cells into milk increases; thus, SCCs >1,000,000 cells/mL are common in uninfected does in late lactation. Proper milking procedures and good environmental sanitation are needed to reduce the prevalence and spread of infection. Chronically infected does should be culled, as should does with M mycoides infections and those that do not recover from M putrefaciens or M capricolum infections.

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