The effects of feeding prebiotics, antibiotics, and alternative proteins during the preweaning period to dairy calves on growth, health, and the gastrointestinal microbiota
Antibiotics fed at subtheraputic levels have been used improve growth and help prevent disease in dairy calf milk diet for decades. Recent changes to the regulations of antibiotics added to feeds have led to prebiotics being proposed as viable options to be used as non antibiotic feed additives. These additives function to improve health and growth rates by maintaining a healthy commensal microbial population in the gastrointestinal tract. The objective of this study was to evaluate three different prebiotics' effects on growth and health in dairy calves when added to the milk diet. Four hundred eighty two dairy calves were randomly assigned to one of four milk diet treatments: control diet (CON) a Galactooligosaccharide additive diet (GOS) carob meal additive diet (CAR) or a butyric acid additive diet (BA) Weight gains, morbidity, mortality, and mitogen proliferation with related cell counts were measured. Calves supplemented with GOS, CAR, and BA were all found to respond with prebiotic effects in comparison to the CON group. Supplementation with GOS significantly improved weight gains the first 77 d of age, increased T lymphocyte stimulation in the first several weeks of life, and provided a long lasting positive effect on Blymphocyte stimulation when stress was simulated. Supplementation with CAR increased Blymphocyte stimulation with and without the presence of stress and decreased the number of diarrhea treatments provided. Supplementation with CAR did not improve T lymphocyte stimulation and significantly increased pneumonia treatments administered. Similar to GOS, supplementation with BA significantly increased weight gains the first 77 d of life and increased Tand B lymphocyte stimulation when introduced to stress. Calves on the BA diet had more diarrhea treatments, but less treatments for pneumonia. These results further