Effects of mannan oligosaccharides on performance and microorganism fecal counts of calves following an enhanced-growth feeding program

Abstract

Sixty female Holstein calves were used to study the effect of mannan oligosaccharides (MOS) on performance, health, bacteria fecal counts and Cryptosporidium presence in feces of calves following an enhanced-growth feeding program. Calves were divided in two groups: supplementation of 4 g/d of MOS on milk replacer (MR-M) or non-supplemented milk replacer (MR-C). After 1 wk of adaptation to milk replacer (MR) at 180 g/kg dilution, calves were fed: 4 l/d of MR from 1 to 7 d, 6 l/d from 8 to 14 d, 7 l/d from 15 to 21 d, 6 l/d from 22 to 28 d, and 3 l/d once daily in the afternoon meal from 29 to 34 d. Calves were weaned at 35 d of study, and were offered water and starter ad libitum until 41 d of study. Starter and MR intake were recorded daily. Calves were weighed weekly, and blood samples were obtained at 1, 3, 5 and 6 wk of study to determine haptoglobin serum concentrations. Moreover, total fecal counts of Clostridium perfringens and Escherichia coli, and for presence of Salmonella spp. and Cryptosporidium spp. were determined from fecal samples obtained at 1, 2, and 3 wk of study. There were no differences in body weight, but starter intake tended to be greater (P=0.09) during the pre-weaning period (0.34 versus 0.28 ± 0.023 kg/d) and greater (P<0.01) the week after weaning (1.94 versus 1.71 ± 0.044 kg/d) in MR-M compared with MR-C calves. However, there were no differences in average daily gain between treatments during the pre-weaning (0.91 versus 0.90 ± 0.017 kg/d), and the post-weaning period (1.20 versus 1.22 ± 0.074 kg/d) between MR-C and MR-M, respectively. Consequently, the gain to feed ratio was lower (P<0.05) during the pre-weaning period (0.70 versus 0.74 ± 0.010), and tended to be lower during the post-weaning period (0.59 versus 0.66 ± 0.033) in MR-M than in MR-C treatment. Serum haptoglobin concentration was similar in both treatments. There were no differences in E. coli fecal counts between treatments. Calves in the MR-M treatment had lower Cryptosporidium spp. presence in feces during the first wk of study (P<0.05), but there were no differences thereafter. The supplementation of MOS in the MR stimulated starter intake after weaning, but this supplementation did not show a determining effect on reducing bacteria counts or Cryptosporidium spp. presence in calf feces, nor in rate of growth.