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Diet is the main source of energy needed for normal physiological functionsof cow, is most important part of its production management process. Different dietarysources of feed and nutrient composition will directly affect the normal physiologicalfunction of the cows, the ultimate expression of affect the cows weight, milk yield andmilk composition changes。For further study of the effect of different types of diets onbody condition of lactating dairy cows, rumen fermentation and productionperformance，20healthy Holstein cows with similar body weight (500±50kg),lactation days（136±37days）, parity, body condition and milk production werechoosed,10cows install with permanent ruminal and duodenal cannulas, and wererandomly divided into two treatments, the first treatment of experimental diets mixedconcentrate and corn stalks single roughage for the CS treatment; second treatment ofexperimental diets mixed concentrate and alfalfa, chinese wildrye, wrapping the wholeplant corn silage high quality mixed forage for the MF treatment, cows unifiedmanagement, feeding twice a day, free drinking water, the pretest period of2weeks,the positive test of5weeks.The results showed that:(1) In cow body condition, the first, second and third testweek of MF cows DMI was significantly higher than the CS treatment (P <0.05),throughout the test period, MF cows DMI was higher than the CS treatment, and thedifference was significant(P <0.05). CS treatment DMI range of18.89to19.22kg/d,and MF treatment is19.88to20.54kg/d, the DMI during the test period no greatervolatility of two treatments, cows feeding more stable. There was no significantdifference between the weight of two treatments (P>0.05). Throughout the test period,the CS treatment BCS varied between2.72to2.90, the MF treatment between2.84to3.11changes, fluctuations are extremely small, between the two treatments of cowsBCS was not significant different (P <0.05).(2) In the rumen fermentation, twotreatments of cows rumen fluid pH showed changes in volatility and fluctuation of thehighest value at half an hour before feed, and during food ruminal pH value downquickly, reached minimum value at the end of the feed, after the end of the feed it was gradually increased until the next feed half an hour before the peak during the feedshowed a decreasing trend, so the law of the cycle of change. The MF treatment rumenpH lower than the CS treatment, but has not significant difference (P>0.05). Themean of CS treatment rumen liquid ammoniacal nitrogen is also higher than the MFtreatment in the day under normal physiological conditions, and the difference wasextremely significant (P <0.01). Rumen liquid ammoniacal nitrogen in the day alsopresents the variation of the volatility, the highest value at the end of the feed (10:30and22:30). MF treatment rumen acetic acid higher than the CS treatment, and thedifference was significant (P <0.05), the CS treatment ruminal propionic acidconcentrations were significantly higher than the MF treatment (P <0.05), the CStreatment rumen butyric acid and valeric acid concentration was extremelysignificantly higher than the MF treatment (P <0.01), total volatile fatty acidconcentrations in the rumen was no significant difference (P>0.05), acetic acidpropionic average was extremely significantly lower than the MF treatment (P <0.01).(3) In the blood biochemical parameters and production performance, blood TP andFFA content was no significant difference of two treatments cows (P>0.05). CS cowsblood BUN and BHBA content was extremely significantly higher than the MFtreatment (P <0.01), and ALB content also significantly higher than the MF treatment(P <0.05). And GLU and TC of MF cows blood was significantly higher than the CStreatment (P <0.05). The MF treatment milk yield was significantly higher than theCS treatment (P <0.05). Compare milk component of two treatments cows that nosignificant difference for milk protein, casein, non-fat solid and lactose (P>0.05). CStreatment milk urea nitrogen was extremely significantly higher than the MF treatment(P <0.01), somatic cell count was also significantly higher than the MF treatment (P <0.05). The fat percentage and total solids in milk component in the MF treatment weresignificantly higher than the CS treatment (P <0.05). Analysis all the results ofvarious aspects can be obtained: MF diet compared to CS diet can improve DMI ofcows, does not affect weight and body condition score of cows, had no effects onrumen pH and total volatile fatty acid concentrations, but the CS diet can affect thebalance between protein degradation and synthesis in the rumen. MF diet can increasemilk yield, improve milk quality and production performance.
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