Impact of direct-fed microbials supplementation on productivity of dairy cows at mid-lactation [electronic resource].

Includes references.

This study was undertaken to determine the effects of direct-fed microbials (DFM, Ru-Max) supplementation on dry matter intake as well as milk production and composition and blood metabolites in high producing Holstein dairy cows at mid-lactation (136±16.9 days in milk). Ninety lactating multiparous Holstein dairy cows (570±11.3 kg live body weight) at mid-lactation were randomly assigned into two experimental groups and fed a total mixed radon (TMR) without or with 20 g of direct-fed microbials (DFM) per cow per day for 10 weeks. Dry matter intake was improved (P<0.014) when DFM was supplemented to the TMR fed to the dairy cows at mid-lactation compared to the control group. The inclusion of DFM improved (P<0.007) milk yield (38.8 vs. 37.5 kg/cow/d) and fat corrected mi1k (FCM, 36.8 vs. 35.0 kg/cow/d) in dairy cows at mid-lactation compared the control group, while DFM supplementation had no effect on feed efficiency compared to the un-supplemented dairy cows. The results of milk yield and the percentages of milk composition varied between treated and untreated dairy cows. Fat percentage and yield was enhanced significantly when DFM was added at mid lactation, while percentages or yields of protein and lactose were not affected by DFM inclusion. The solid not fat (SNF) yield was improved (P<O.Q09), while SNF percentage did not differ between DFM and control group of dairy cows. Serum concentrations of total protein, albumin, globulin, urea, glucose, cholesterol, triglycerides and creatinine were not differed significantly between supplemented dairy cows with DFM and the un-supplemented group. The daily net profit due to DFM supplementation was 1.44 EGP per cow at mid-lactation. The above results indicated that DFM have the potential to economicallly promote milk yield at mid-lactation of high producing dairy cows.

Summary in Arabic.

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