Effects of Mannan oligosaccharides in the diet of beef cattle in the transition period

The aim of the study was to determine the effects of mannan oligosaccharide (MOS) supplementation to beef calves diet on performance during the first phase of the cattle fattening cycle (the transition phase). A total of 48 male Blond d’Aquitaine calves with an average weight of about 225 kg, just arrived together from France, by lorry after a 8 hours lasting journey. They were housed in 8 pens with straw bedding (6 calves per pen) and divided into two treatment diets: Control (straw and pellet feed) or MOS (Control diet plus 0.4% in pellet feed of MOS - BIO-MOS®, Alltech, Inc.). The trial was carried out over a 48 days period. On their arrival day, all calves were vaccinated against respiratory illnesses, BVD and treated with Ivomec®. After about 20 days a second vaccination took place (booster). Body weight was recorded at day 0 and 48. Feed consumption was evaluated daily for each pen; blood samples were taken from the jugular vein of 12 calves per group on days 0, 22 and 48. Feed and straw consumption was similar in the two groups (average 3.968 kg /head/ day of pellet feed for Control Group and 3.990 kg/head/day for MOS Group). The total average increase in weight was numerically higher (+3,6%) in MOS group than in Control Group (57.840 kg vs 55.835 kg) as well as daily weight gain (1.205 kg/day vs 1.163 kg/day respectively for MOS and Control group). As far as the blood proteins are concerned, the albumin values were unchanged (48.71% vs 48.84% respectively for Control group and MOS), while a significant difference (P=0.017) in the alpha globulins was seen on the 48th day of the trial (17.65% vs 16.34% respectively for Control and MOS) and in beta globulins (P=0.018) as average over the total trial period (11.57% vs 10.81%, respectively for Control and MOS). Gamma globulins concentrations showed slightly higher values in the MOS group but were not significantly different (25.68% vs 27.41% on the 48th day and average values of 22.28% vs 23.25%, respectively in the Control and MOS Groups). NEFA values were significantly lower in MOS Group on the 48th day of research (124.58uEq/l vs 195.42 uEq/l; p=0.046) demonstrating that the mobilization of the fatty acids was significantly lower in the MOS group. It can be concluded that the calves treated with MOS showed lower levels of stress and showed a better immune system response in this delicate phase in the fattening process.