Calf morbidity and mortality represent major financial losses for many dairy producers. The primary cause of calf mortality in the U.S. is diarrhea caused by intestinal bacterial infections. Traditionally, formulated antibiotics in milk replacer have been used as preventive treatments. However, as consumer concern about antibiotic resistance has increased, interest in alternative supplements has grown. Prebiotics, which are food ingredients not digestible by animal enzymes, and probiotics, which are beneficial bacteria, are two proposed alternatives for antibiotics to reduce diarrhea and improve immunity in calves. In this trial 75 Holstein heifer calves were randomly assigned to one of 3 treatments: control (C; no additive), antibiotic treatment (A; oxytetracycline 0.220 g/kg and neomycin base 0.441 g/kg), and prebiotic supplement (PB; 20 g/day Prebio Support™, Meiji Feed Co., Ltd. Tokyo, Japan). Calf scours, respiratory, and general appearance scores were not affected by treatment. No statistical differences were detected in any of the health data collected; however, treatment C had nearly twice as many calves that scoured and refused feed than treatments A and PB. Populations of beneficial and pathogenic bacteria in feces were generally not affected by treatments. However, PB treatment calves had an overall trend for more Lactobacilli in their feces than calves fed A (P = 0.08), and Enterobacter population was greater in C calves than in calves on treatment A in week 4 (P < 0.05). There was a tendency for the PB treatment to have elevated populations of beneficial species of bacteria during week 2. Populations of lymphocytes carrying CD4 and CD8 markers were not affected by treatment. Fecal IgA concentration decreased as calf age increased, with the greatest concentration in week 2 (P < 0.01) for all calves. Fecal IgA levels were numerically greater for the PB group in weeks 2 and 4. Both PB and A treatments affected fecal parameters with PB having positive effects in several areas. Since calves in this study were generally healthy, observable benefits from the treatments were likely minimized.
All Science Journal Classification (ASJC) codes
- Animal Science and Zoology