Clinical and laboratory findings in cases of toxic mastitis in cows in Northern Ireland

This paper describes the clinical and laboratory findings from 264 cases of toxic mastitis in cows in Northern Ireland between October 1995 and May 19 97. Nearly all the cases occurred during the winter housing period, with 84 per cent occurring between November and March inclusive, and 30 per cent i n March. Sixty per cent of the cases occurred within one month of calving, and 29 per cent within four days of calving. The most common clinical signs were lethargy (92 per cent), discoloured milk (90 per cent), anorexia (72 per cent), tachypnoea (23 per cent), diarrhoea (23 per cent), recumbency (1 8 per cent) and staggering (15 per cent). Severe pyrexia (18 per cent) and clinical dehydration (44 per cent) were relatively common findings. Pure gr owths of Escherichia coli were isolated from 50 per cent of the milk sample s, but 11 per cent yielded no bacterial growth. In vitro sensitivity tests indicated that enrofloxacin was effective against 98 per cent of the bacter ia isolated, and framycetin and amoxycillin/clavulanic acid against 91 per cent. Abnormally high blood urea levels were observed in 31 per cent of cas es, high blood creatinine levels in 42 per cent, and severe leucopenia in 5 6 per cent. Of the cases which were followed up, 14 per cent died, 21 per c ent were culled early and a further 22 per cent lost milk production from t he affected quarter.