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Background Liquid feed are the major nutrient source that can have a significant impact on the growth and development of immune system of calves before weaning. Waste milk containing antibiotic residue has been produced because of the continuous expansion of dairy farms. In order to reduce economic loss and prevent environmental pollution, most farms seem waste milk as one of the calves’ liquid feeds. However, there is limited information to report the effects of waste milk on growth performance, especially immunity function of calves. Thus, the objective of this study was to investigate the effects of waste milk on growth, immunity and gut health of dairy calves. Results Feeding WM improved hip width, hip height, heart girth, final body weight, and feed efficiency of dairy calves compared to MR. Plasma concentrations of IgA, IgM, IgG and IL-10 were higher and TNF-α was lower in WM group. In addition, treatment and time interactively affected plasma concentrations of IgG and IL-2, which increased and decreased in WM group but decreased and increased in MR group, respectively, from 49 to 70 d of age. There was no difference in diarrhea case and average days of diarrhea among treatments. Difference in fecal microbiota was observed between MR and WM groups only at 49 d of age. Analysis of differential abundance showed that the increase in the relative abundance of Prevotellaceae NK3B31 group and the decrease in that of Bacteroides was higher in WM than MM group from 49 to 70 d of age. Conclusions WM had beneficial effects on growth performance and did not affect health statue, which might be explained by enhanced immune function modulated by fecal microbiota. |
