Cephamycin C is a
beta-lactam antibiotic that has broad gram-negative activity and is resistant to degradation by
beta-lactamases and safe for use in animals. In colostrum-fed calves infected with Escherichia coli strain B44,
cephamycin C administered by gavage at 31.3 to 1,000 mg per calf (0.75 to 24 mg/kg) twice a day for 6 days starting at 20 h post-inoculation eliminated the
diarrhea and reduced the mortality from 90% in infected, nonmedicated calves to 14% in infected, medicated calves (P < 0.01). Comparable results were obtained with a shorter treatment regimen (30 mg of
cephamycin C per calf [0.71 mg/kg] twice a day for 3 days). In colostrum-fed piglets infected with E. coli strain P155 and housed in cages,
cephamycin C administered prophylactically by gavage at 12.5 mg per piglet (10.4 mg/kg) twice a day for 4 days completely prevented both
diarrhea and mortality, whereas nonmedicated piglets had 100%
diarrhea and all died. When eight doses of
cephamycin C were given therapeutically starting at 6 h post-inoculation, mortality was reduced from 79 to 23% (P < 0.02), and
diarrhea was eliminated in the surviving medicated piglets by 4 days post-inoculation. In infected suckling piglets,
cephamycin C administered therapeutically by gavage at 12.5 mg per piglet twice a day for 3 days starting at 6 h post-inoculation,
diarrhea and mortality were reduced (P < 0.05): infected, nonmedicated piglets had 87%
diarrhea and 75% mortality, whereas infected, medicated piglets had 25%
diarrhea and 31% mortality. All surviving medicated piglets had solid feces by 2 days post-inoculation. Thus,
cephamycin C was highly effective in restoring the calves and piglets to good health by eliminating
diarrhea and reducing mortality.