Effects of using Different Additives on Blood Metabolites, Digestibility of Nutrients and Production Performance of Dairy Cows

The purpose of this study was to determine the effects of supplementation of probiotic and peri-biotic supplements in dairy cows on quantitative and qualitative yield of milk, feed intake, digestibility of nutrients, and blood metabolites. Forty Holstein dairy cows with daily milk production of 37 ± 5 kg and initial weight of 700 ± 40 kg were divided into four groups in a completely randomized design. The experimental treatments consisted of: 1- control group (basal diet), 2- probiotic group (basal diet + 4 gr probiotic per head per day), 3- prebiotic group (basal diet + 14 gr perbiotypes per Ross per day), 4- Synbiotic group (basal diet + 4 gr probiotic + 14 gr perbiotic per head per day). The amount of feed consumed per cow was recorded throughout the entire period. Milk samples were collected twice a week for determining the milk composition. The milk composition, (fat, protein, lactose and fatty solids) was measured. Total feces were collected to determine digestibility in the last 7 days of experiment. In the last day of experiment, blood samples were taken at 4 hours after morning feeding by venogecte tubes. Rumen fluid were collected at 4 hours after morning feeding and immediately determined by pH. The results of the experiment showed that the amount of daily milk production and fat content increased and there was a significant difference with the control group (basal diet without additive) (p<0.05). The results of the average dry matter consumption indicated that there was no significant difference between different diets.The highest digestibility coefficient of dry matter, fat and organic matter belonged to the group that consumed probiotics and had a significant difference with other groups (p<0.05). Concentration of plasma glucose increased with increasing probiotic content, which caused a significant reduction in the control group compared to other diets (p<0.05). With the use of probiotic, the pH of ruminal fluid in experimental animals did not change and there was no significant difference with other treatments (p<0.05). In general, it can be concluded that probiotic supplements used in this study can improve the yield of dairy cows, but have no significant effect on the digestibility of nutrients.