Studies on pathological conditions in the mammary glands of cattle and goats

Abstract

An investigation was carried out to study the pathological lesions encountered in the mammary glands of cattle and goats from specimens selected from slaughter house and autopsy cases. The somatic cell count in milk from clinical and sub – clinical cases of mastitis was also undertaken. Two hundred quarters from cows and 67 halves from goats were subjected to detailed histopathological investigation. Mastitis was found to be the important type of lesion encountered. Lesions varied from subtle changes to intensive involvement with complete obliteration and atrophy. The lesions encountered were catarrhal mastitis and galactophoritis, suppurative mastitis, acute diffuse mastitis, necrotising mastitis, gangrenous mastitis, interstitial mastitis and tuber - culous mastitis. Other significant alternations associated with or without mastitis were congestion and oedema, squamous metaplasia of lining epithelium of ducts and cisterns and calcification of vessel walls. The calcification of the vessels was similar to that observed in ‘Monckeberg’s sclerosis’ in human beings. No tumours were found. It was suggested that lymphoid cells found in the interstitial septa of the mammary glands of goats affected with John’s disease might be the ‘T’ type of lymphocytes which are concerned with cellular immunity. The cystic changes encountered in the glands were not considered as the separate entity – Fibrocystic disease – but only compensatory processes as a result of fibrosis and atrophy of some part of the glandular and ductal system. Micro concretions were constantly observed and it was suggested that calcium got deposited over inspissated and hyalinised milk proteins. A total of 189 quarter samples of milk was also examined for total somatic cell count, differential count and by culturally for the presence of pathogenic bacteria and fungi. The total cell count in normal milk of cows and goats varied from 150,000 to 500,000 per ml. In sub – clinical and clinical cases upto 30,000,000 cells per ml could be counted. The percentage of neutrophils in normal milk was below 31% in goats and 43% in cows. The corresponding maximum values in mastitic cases were 88% and 92% respectively. In both cows and goats the chief etiological agent for mastitis as found in the present study was Staphylococcus. Other organisms encountered were Strephylococcus, Coliforms and Corynebacteria.