Outbreak of endemic form of protothecal mastitis on a dairy farm

Abstract

In this paper an outbreak of mastitis in cows resistant to antibiotic treatment on a Holstein-Friesian cattle farm in Vojvodina (Serbia and Montenegro) was described. Microbiological examination of 73 milk samples from lactating cows revealed the presence of Prototheca zopfii in 22 samples (30.13%). Identification of the isolates was performed on the basis of growth features, microscopic appearance, assimilation patterns and antimicrobial susceptibility. Protothecal infection of the mammary gland resulted in clinical symptoms of chronic mastitis in 19 animals. Histopathological findings revealed distinct granulomatous inflammations of the mammary gland interstitium.