RESUMEN
Seven isolates of Mollicutes, Mycoplasma F-38; M. mycoides var. capri; mixed isolates of M. bovigenitalium and M. bovirhinis; M. bovigenitalium, Mycoplasma F-38 and M. bovirhinis; M. bovis, M. bovigenitalium, Mycoplasma F-38 and A. laidlawii; A. axanthum; A. laidlawii from bovine udders and a M. bovis type strain (NCTC-10131) produced significant histopathological changes characterized by infiltration of neutrophils in lumen of acini, interlobular and intralobular ducts along with the hyperplasia of lining cells of acini, interlobular and intralobular ducts and infiltration of mononuclear cells and fibroblasts in interstitium in the mammary gland of rat suggestive of mastitis. A. laidlawii and A. axanthum produced only mild changes suggestive of their negligible role in the bovine mastitis. Rat mammary gland is recommended as a suitable in vivo experimental laboratory model to screen the mastitogenic potential of Mollicutes.