Oligosaccharides for Dairy Calves

There is limited information on feeding mannan-oligosaccharides (MOS) and fructo-oligosaccharides (FOS) to calves despite the popularity of these products in the livestock feed industry. A total of 144 Holstein calves (initial BW 44 kg and <7 d old) were used in 3 trials that were conducted to evaluate FOS and MOS as dietary additives. In trial 1, 24 calves/treatment were fed 0.454 kg/d of a 20% CP, 20% fat, 0.05% decoquinate milk replacer (MR) that provided 0 or 4 g FOS/calf daily. In trial 2, 24 calves/treatment were fed 0.454 kg/d of a 20% CP, 20% fat, 0.05% decoquinate MR that provided 0 or 8 g FOS/calf daily. In trial 3, 24 calves/treatment were fed 0.681 kg/d of a 26% CP, 17% fat, 0.03% decoquinate MR that provided 0 or 6 g MOS/calf daily. In trials 1 and 2, calves were weaned at 42 d; in trial 3, calves were weaned at 28 d. In all 3 trials, calves were fed free-choice water and 18% CP, 0.03% decoquinate starter throughout the 56-d trials. In all 3 trials, addition of FOS or MOS did not change ADG (0.514, 0.473, and 0.478 kg/d in trials 1, 2, and 3, respectively) feed intake, feed efficiency, or days with scours in calves under 2 mo of age.