RESUMO A Mastite em éguas é considerada uma doença rara sendo o Streptococcus equi. Staphylococcus sp., Corynebacterium sp., Actinobacillus sp., Nocardia sp. e as enterobacterias os micro-organismos mais frequentemente envolvidos. A doença está relacionada a injúrias e traumas nas mamas e tetos. Edema e fibrose da glândula mamária, leite com aspecto viscoso ou muco-purulento são observados nos casos de mastite clínica. O diagnóstico é baseado no exame clínico da mama associado ao cultivo microbiológico do leite. Os métodos indiretos para o diagnóstico de mastite subclínica como California Mastits Test e Contagem de Células Somáticas não são padronizados para a espécie em questão. A terapia para a mastite equina é baseada no uso sistêmico de antimicrobianos, com base nos resultados obtidos no teste “in vitro” de sensibilidade microbiana. Não há medidas de controle específicas para a mastite equina. Objetivou-se neste estudo revisar os principais aspectos relacionados a mastite em éguas com ênfase na etiologia, epidemiologia, sinais clínicos, diagnóstico, tratamento, medidas de controle e profilaxia.

ABSTRACT Mastits is considered uncommon disease in mares. Streptococcus equi. Staphylococcus sp., Corynebacterium sp., Actinobacillus sp., Nocardia sp. and enterobacterias are major microorganisms involved in equine mammary infections. The disease is commonly related to traumatic lesions in mammary glands and teats. Edema, fibrosis, masses to palpation of glands, and viscous to seropurulent milk are mainly clinical signs observed in affected animals. The diagnosis is based on clinical exam of mammary glands and microbiological culture of the milk. There are no standard to use of indirect exams on diagnosis, including California Mastits Test and Somatic Cell Count. Systemic antimicrobials are recommended in therapy, based on previous “in vitro” susceptibility microbiological test. No specific control measures are indicated in equine mastits. The present study reviewed the mastits in mares, with emphasis to etiology, epidemiology findings, clinical manifestation, diagnosis, treatment and control aspects.

Routine diagnosis methods used in bovine mastitis were studied in 55 mares in lactation. The findings of strip cup test, California Mastitis Test-CMT, electronic somatic cell count-CCS, microbiological culture, and in vitro antimicrobial susceptibility profile of isolates were discussed. Streptococcus spp., Staphylococcus spp, and enterobacteria were the most common microorganisms isolated in health and CMT-positive mammary glands. Staphylococcus aureus and Arcanobacterium pyogenes were identified in two mares presenting clinical mastitis. Mean somatic cell count of eight mares without presence of microorganisms in milk was 247.57x10³/mL and 1.621,86x10³/mL in 47 mares with positive microbiological culture. Moderate concordance (63.8%) between positive reactions in CMT (1 to 3+) and microbiological culture was observed. Amicacin (78.9%), ceftiofur (74.7%), sulpha-trimetoprim (69,0%) and norfloxacin (69.0%), were the most effective drugs, while resistance of isolates was mainly observed against penicillin (64.8%), gentamycin (35.2%), azithromycin (35.2%), enrofloxacin (28.2%), and florfenicol (28.2%).

An uncommon outbreak of mastitis caused by Arcanobacterium pyogenes in 26 cows is reported. The epidemiological findings, clinical signs, microbiological exams, somatic cell count, in vitro susceptibility profile of strains, efficacy of intramammary treatment and control measures were discussed. Florfenicol (96.2%), cefoperazona (92.3%), cefaloxin (84.6%) and ceftiofur (84.6%) were the most effective antimicrobials, and neomicin (27.0%) and enrofloxacin (17.4%) the least effective antimicrobials.