Effects of oral antibiotics or bovine plasma on survival, health and growth in dairy calves challenged with Escherichia coli

Thirty-six Holstein bull calves were fed experimental milk replacers (454 g /day(-1)) containing 20% crude protein and 20% fat. Milk replacers containe d no additives, antibiotics (800 mg neomycin (as neomycin sulfate) and 400 mg oxytetracycline daily replacing dried whey, or 3.3% spray dried bovine p lasma replacing whey protein concentrate. Calves were orally challenged wit h approximately 10(8) colony forming units (CFU) of enterotoxigenic Escheri chia coli on day 3. No veterinary treatments or supportive therapy were pro vided during the study. Calf body weight (BW) was determined weekly and ave rage daily BW gain was calculated. Clinical scores were determined daily fo r fecal consistency, attitude and hydration. All clinical scores responded to oral E. coli challenge. Provision of antibiotics and animal plasma had n o effect on fecal consistency but improved attitude and hydration scores, b ody weight gain and tended to reduce overall mortality. Spray dried animal plasma appears to be a viable alternative to antibiotics in calf milk repla cer applications.