Experimental Mycoplasma mastitis in cattle. I
Horváth, G.; Stipkovits, L.; Zöldág, L.; Varga, Z.; Mészáros, J.
Acta Veterinaria Academiae Scientiarum Hungaricae 29(3): 223-231
1981
ISSN/ISBN: 0001-7205 PMID: 7348098 Document Number: 169567
Eight udder quarters from 5 cows (1 Holstein-Friesian, 4 Hungarian Red Pied) were infected with a Mycoplasma bovis culture by intra-cysternal infusion, in 3 cases at 5-6 wk of lactation and in 2 cases near its end. Clinical course and milk changes were followed-up, the infected and control quarters were examined bacteriologically and biopsies were taken for histological study. All M. bovis strains used for experimental infection elicited an acute parenchymal mastitis in the infected quarters. The milk yield decreased considerably by 4-8 h postinfection (p.i.) and agalactia set in abruptly after 72-96 h. The milk showed a yellowish discoloration, its consistency became colostrum-like and its cell count rose to several million within 4-8 h p.i. Cytologically, predominance of neutrophilic granulocytes was demonstrated in the milk. The Cl- concentration rose to > 148 mg/100 ml (maximum 612 mg/100 ml) in secretions from infected quarters. The mycoplasma count of the milk rose to the order of 109-1010 colony-forming units/ml within 2-5 days p.i. In every case infection spread to the intact quarter of the same udder half, and/or from one udder half to the other by 5-6 days p.i.