Prospects for the use of a <i>Bacillus subtilis</i> metabolites-based feed additive in dairy farming

Abstract

Laboratory and field experiment on use of the feed additive based on Bacillus subtilis endo- and exometabolites for the cows in different physiological periods are described in the paper. The feed additive impact on main body systems of the tested cows (n = 30), milk production parameters, growth rate of the calves (n = 18) born to the said cows were examined. The feed additive was added to the diets for the cows of test groups, 15 g per cow. The feed additive was found to have a positive effect on immunohematological and metabolic processes in postpartum cows. Neutrophils’ phagocytic activity increased by 12.5% and 14.6% in the animals of test group 1 and test group 2, respectively, as compared to that one in control animals (42.8 ± 1.9%). Neutrophil absorbency increased by 2.5 times, 3.2 times and 2.1 times in the animals of test group 1, test group 2 and control group, respectively. The proportion of T-lymphocytes in blood of animals in test group 1 and test group 2 was 44.5 and 48.9%, respectively, proportion of T-lymphocytes in blood of control animals equaled to 37.5%. Trend for increase in total protein concentration in cow sera owing to increase in albumin fraction was observed in postpartum period: it was 72.91 ± 3.45 g/l in test group 1; 75.54 ± 4.12 g/l in test group 2; 70.95 ± 4.25 g/l in control group. Average daily milk yield in cows of test group 1, test group 2 and control group for the 150 days of lactation was 24.50 ± 1.86 kg; 25.33 ± 1.45 kg and 22.75 ± 4.41 kg, respectively. Higher growth rate was reported for the calves born to the cows received the diet supplemented with the said feed additive. Heifers of test group 1 and test group 2 have reached body weight of 193.51 ± 5.76 and 195.33 ± 3.76 kg and in control group – of 187.33 ± 4.98 kg within 6 months. Feed additive based on endo- and exometabolites of Bacillus subtilis is recommended for cow diets for highly productive dairy herd creation and food-producing animal welfare maintenance.