47 Effects of Lactobacillus and Bacillus Probiotics on Pre-ruminating Calf Growth Performance and Efficiency

Abstract

Abstract Lactobacillus and Bacillus probiotics may serve as an alternative to antibiotics in milk replacer for pre-ruminant calves by altering gastrointestinal microflora to prevent the proliferation of harmful bacteria. However, there are limited studies evaluating their impact on calf growth and efficiency. The objective of this trial was to discover the impact of probiotic-containing milk replacer on pre-ruminating calf growth performance. A total of 44 pre-ruminant calves (50% Angus/50% Holstein, average weight 39.3 kg + 7.5 kg) were fed milk replacer with either no probiotic or 1.25x10^9 colony forming units/head/day of a probiotic blending containing Lactobacillus and two different Bacillus species (Church & Dwight Animal Nutrition (Princeton, NJ). Calves were blocked by age and randomly assigned within block to one of two treatments in a randomized complete block design. Calf was the experimental unit, with 22 calves per treatment. Calf weight and hip height was measured on d 0 and 30 to calculate average daily gain (ADG) and average growth per day. Calves were offered 1.36 kg milk replacer [15% dry matter (DM)] twice daily and up to 0.5 kg starter feed (88% DM) once daily. Refusals were recorded to calculate average daily intake and gain to feed ratio (G:F). Initial weight differed (P = 0.020) between treatments, and was therefore used as a covariate in all response criteria. Calves fed milk replacer with probiotic had greater (P < 0.05) ADG (0.53 vs. 0.42 kg/d, respectively) and G:F (0.50 vs. 0.41, respectively) than those fed the control. There was no evidence (P >0.05) that probiotic inclusion impacted hip height on d 30 or daily intake. In summary, Lactobacillus and Bacillus probiotic inclusion in milk replacer improved calf growth performance without impacting intake. Subsequent research is warranted to elucidate mode of action and evaluate impact relative to an antibiotic-containing positive control.