عنوان مقاله [English]
Background and Objectives: Numerous investigations with dairy cow supported the positive effects of live yeast supplementation on productive efficiency, which were mainly linked to the improved efficiency of rumen fermentation and nutrient digestion. live yeast supplementation has positive effects on reproduction performance with increase of feed intake in high ambient temperature. Recent findings are also revealing the immunomodulating effect of yeast culture in dairy cows, which is possibly linked to the improved energy status as well as the interaction between yeast components in the gut that contributes to the activation of the immune response. The objectives were to determine effects of feeding a live yeast culture as a probiotic on the productive performance, feed intake and some blood metabolic profiles of dairy cows under the hot months of summer.
Materials and methods: The study was implemented 85 days (from June to September 2017) at the FKA Agri-Animal Production Co (Isfahan, Iran). Two groups of 6 periparturient Holstein cows were fed a diet without or with 4 g yeast/d/head (15*109 CFU/g) starting 21 d prepartum through 8 wk postpartum to investigate the changes of blood concentrations of non-esterified fatty acids, β-hydroxybutyrate and Urea-N. Blood was collected on d −14, 0, 14, 28, and 60 d relative to parturition. Diets were mixed twice daily in prepartum and three dailies in postpartum and offered as a TMR. Weekly milk samples were obtained from each cow from 3 consecutive milking (08:00, 16:00, and 00:00), and individual milk weights were recorded at each milking for each cow using a Waikato MKV milk meters (Inter Ag, Hamilton, New Zealand).
Results: Relative to control, cows receiving yeast culture had higher milk yield, milk fat content, and milk solids content. Prepartum DMI was greater in yeast-fed cows than those receiving no yeast but postpartum no significant effect in two groups. None of the blood metabolites analyzed were affected with yeast supplementation, However, a significant day of sampling was found in all blood metabolites assayed, which is indicative of the considerable alterations in metabolic status of dairy cows around the time of calving. In treatment group percentage of glucose increase and BUN decrease.
Conclusion: Yeast supplementation of dairy cows during the high ambient temperature improved lactation performance. Overall, it appears that Probiotics would beneficially improve the blood concentrations of glucose and reduction of BUN in day 60 postpartum (on DFS day). To put into and pay attention to positive results of probiotics to milk production, reproduction, immune function and etc. they are useful in ration of dairy cows in all the sessions to make the peak of generation into the minimum condition.