BACTERIOLOGICAL CULTURE OF BLOOD FROM CRITICALLY ILL NEONATAL CALVES

The objectives of this study were to estimate the prevalence of bacter emia in critically ill, neonatal calves with severe diarrhea or depres sion, and to describe the variety of bacteria involved. Two studies we re conducted in the summers of 1991 and 1993 involving 190 neonatal ca lves, 1-day to 19-days-old. Bacteremia was detected by blood culture i n 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves a nd 0% (0/21) of control calves in study 2. Bacteria cultured from bloo d included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gramnegative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, t he average age was significantly lower in the blood culture-negative g roup (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.0 04). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-ne gative calves (3.077 g/L). The mortality rate was significantly (P < 0 .0001) higher in the blood culture-positive group (57.4%) than in the blood culture-negative group (15.1%). Bacteremia appeared to be a freq uent entity in this particular rearing situation. Early recognition of the problem, as well as appropriate treatment, may be beneficial in i ncreasing survival rates. Results also support the need to address the failure of passive transfer of maternal antibodies to prevent bactere mia in calves.