There was no difference between the groups with respect to body weight ( P = 0.56), or level of serum total protein ( P = 0.48) measured at arrival. To evaluate the effect of treatment group on fecal score, a generalized linear model with a logit link and binomial family was used. A Cox proportion hazard model was built to evaluate the impact of treatment groups on the risk of morbidity, and mortality over the growing period, whereas a mixed linear regression model was built to evaluate the effect on average daily gain.
Body weights were recorded at arrival, 49, and 78. Calves were observed daily for symptoms of respiratory disease. For the first 28 d following arrival, calves were scored for fecal consistency on a scale of 0 to 3 with 0 being normal manure and 3 meaning watery feces. Calf starter (18% CP) was fed for 21 d followed by a mixed corn and supplement (18.1% CP) ration for the remainder of the study. MR was formulated with 26% crude protein (CP) and 17% fat and fed at 0.7 kg powder / d in 2 feedings for 5 weeks followed by 0.45 kg of MR powder / d over a 2-week weaning period. Calves were housed individually until weaning at d 49, then commingled into consecutive groups of 5 until d 78. Holstein male calves (n = 158) were randomly assigned to receive one of 3 formulas containing SDPP, FA, or a control group with no feed additives or non-milk proteins. The objective of this study was to evaluate the health and performance effects of incorporating 2 common feed additives, Bacillus subtilis (1.3 million cfu/g) and 70% sodium butyrate at 2kg/MT (FA), or spray dried porcine plasma (SDPP) at 5% of the milk replacer formula (MR).
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