The Effect Of Ratio Structural And Nonstructural Carbohydrates Of Dietary On Performance And Digestive Metabolism In Early Lactation Dairy Cows

The determination of the appropriate ratio SC:NSC of dietary, that the roughage of formulation were corn silage, corn straw and alfalfa, for maintaining healthy ruminal function and higher productive performance were used the studies of the effect of the ratio of SC:NSC of various dietary on productive performance and digestive metabolism, provided basal information of dietary formulation and the appropriate ratio SC:NSC by combination of the methods in vivo and in vitro in early lactation dairy cows. The ratio of various dietary SC:NSC were as follows: control group(1.02),groupⅠ(0.96), groupⅡ(0.90),groupⅢ(0.90), groupⅣ(0.70) and groupⅤ(0.59).Part one: 30 Chinese Holstein healthy dairy cows in early lactation were randomly blocked by milk yield, parity, lactation days and body weight into 6 groups, studied the effect of 6 ratio of SC:NSC of 6 dietary on productive performance, chewing behavior and blood parameter in early lactation cows.Part two: The effect of 6 ratio of SC:NSC of 6 dietary on disappearance of dry matter(DM), gas production, pH, volatile fatty acid(VFA), bacterial protein(BCP) were studied by in vitro batch incubation.The results of study indicate that: DMI, milk production, FMC production increase with SC:NSC ratio's decreasing, SC:NSC ratio has no effect to milk efficiency(P>0.05). The ratio of SC:NSC had no significant effect to the total tract digestibility of DM,CP,NDF and ADF(p>0.05), however, as the ratio decreasing, the total tract digestibility of DM, had increasing trend and that of NDF and ADF had decreasing trend. The chewing and ruminating time were reducing with SC:NSC ratio's decreasing, total chewing time of control group was significantly longer than groupⅤ(P<0.05). The dietarys'SC:NSC ratio had no notable effect on Urea-N, FFA andβ-hydroxybutyric acid content in plasma(P>0.05). With SC:NSC ratio's descent, pH(P>0.05), acetic acid concentration(P>0.05), and acetic acid/propanoic acid ratio (P<0.01)had decreased, nevertheless, propanoic acid, disappearance of DM and gas production had marked (P>0.05) increased, butanoic acid and TVFA concentration increase first and decrease then(P>0.05). In summary, results indicated that the appropriate ratio SC:NSC of dietary were between 0.59 and 0.70, and relatively poor when was 1.02.