To investigate the effect of direct fed microbial (DFM) on performance of fattening lamb, 4 treatments (7 animals/treatment) were evaluated; (1) control (without additive; CON); (2) Lactobacillus fermentum and Lactobacillus plantarum (FP); (3) Saccharomyces cerevisiae (SC) plus FP (SCFP) and (4) Megasphaera elsdenii plus SCFP (MSCFP). Feed intake, final body and feed efficiency except average daily gain were not affected by experimental treatment. Digestibility of dry matter and organic matter increased (P < 0.05) in MSCFP lambs versus other treatments. The highest (P < 0.05) amount of N intake, absorbed N and N retention were observed in MSCFP lambs. Blood parameters and enzymatic profiles were not affected (P > 0.05) by the treatments. The lowest and the highest of minimum pH were observed in CON and SCFP lambs. Moreover, concentration of ammonia-N, total and individual volatile fatty acids (except acetate and butyrate concentration) and acetate to propionate ratio were not affected (P > 0.05) by treatment. According to the results, the use of microbial feed additives had a positive effect on growth performance and some digestive and ruminal fermentation parameters.

In this experiment, corn – oat, barley – wheat and barley – oats were used as a source of starch in 1, 2 and 3 rations respectively. The ratio of concentrate to forage in all treatments were 35:65. The results showed the concentration of total protein and cholesterol were not affected by the type and source of cereal grains (P > 0.05). Serum glucose and triglyceride concentration significantly increased in corn – oats treatment (P < 0.05). Also, in this experiment total volatile fatty acids (VFA), acetate (A), propionate (P) and A/P concentrations were not affected by the type of cereal grains (P > 0.05), but valerate and butyrate concentrations significantly increased in barley – wheat treatment (P < 0.05). On the other hand, concentrations of isobutyrate and isovalerate significantly increased in corn – oats treatment (P < 0.05). Fecal pH, were not significantly different between corn – oats and barley – oats treatments (P > 0.05), although the lowest pH was observed in barley – wheat treatment (6.02). According to the results, treatment 1 (corn – oats) improved fecal VFA and blood metabolites in the comparison of the other treatments.

Background: The objective of the experiment was to investigate the effect of a mixture of direct‐fed microbial (DFM) on feed intake, nutrient digestibility, milk yield and composition, milk fatty acid and blood parameter in crossbred mid‐lactating cows.Methods: Twenty‐four crossbred Holstein cows (body weight = 650±15 kg; days in milk = 100±20; daily milk yield = 25±3 kg) were used in a completely randomized design with three treatments: (1) CON, without DFM; (2) LS, inoculation with Lactobacillus fermentum (4.5 × 10⁸ CFU/day) plus Saccharomyces cerevisiae (1.4×10¹⁰ CFU/day); and (3) LSM, inoculation with LS plus Megasphaera elsdenii (4.5 × 10⁸ CFU/day). All animals received the same ration with 45.7% forage and 54.3% concentrate.Results: Results showed that the highest feed intake was observed in treatments LS and LSM (p = 0.02). Compared with the CON, milk production, 4% fat‐corrected milk, energy‐corrected milk, fat (kg/day), protein (kg/day) and lactose (kg/day), FE and percent of fat were increased (p<0.05) by LSM, but unaffected by LS. Also, compared with the CON, both LS and LSM increased antioxidant activity (p<0.05). The concentration of C18:2c n‐6 increased significantly in treatment LSM compared with the CON (p = 0.003). The concentration of C20:0 increased significantly in treatment LS compared with the CON (p = 0.004). The highest concentrations of insulin, glucose, triglyceride and cholesterol were observed by LSM (p<0.05). Compared with the CON, both LS and LSM increased blood monocyte, neutrophil, eosinophil and basophil (p<0.05), and blood lymphocyte was increased (p = 0.02) only by LSM.Conclusions: The results of the research showed that the use of DFMs had no effect on the digestibility, microbial load and the major part of fatty acids in milk. However, it improved feed intake, milk yield and antioxidant activity of milk and also increased the milk concentration of C18:2 n‐6.