Pathology of bacterial mastitis in bovines

Abstract

The pathology of bacterial mastitis in bovines was studied considering the following aspects such as bacterial isolation; changes in milk, antibiotic sensitivity pattern, haematology, whey protein pattern and histopathological examination of the mammary gland and supramammary Iymphnodes. Two hundred and sixty two samples were found to be subclinically positive based on California Mastitis Test. The organisms isolated from clinical and subclinical cases were Staphylococcus, E. Coli, Gram negative bacilli, mixed infections, Streptococcus, Yeast and Gram positive bacilli in the decreasing order of prevalence. All the major pathogens were sensitive to pefloxacin, gentamycin and chloramphenicol and resistant to penicillin. Leucopenia could be noticed in clinical and subclinical cases of mastitis. Relative neutrophilia could be observed in mastitic animals. Total plasma protein was also increased. There was an increase in T-Iymphocyte count in mastitis affected animals. ~omatic cell count was increased in clinical and subclinical cases, but was not indicative of infection, unless confirmed by bacteriological examination.

SOS-PAGE on whey proteins revealed an increase in protein content in mastitic milk as a result of the plasma proteins, cellular proteins, bacterial proteins. There was marked increase in immunoglobulins in mastitic milk, when compared to normal. Histopathology of mammary glands revealed the presence of inflammatory cells in the acini and interstitium of mammary glands as the main lesion. Varying degrees of inflammatory reaction could be noticed in almost all the quarters. Supra mammary lymph nodes revealed distension of subcapsular sinuses, active secondary follicles in the cortex, sinus catarrh and medullary hyperplasia in mastitis affected animals.