Effects Of Exogenous Fibrolytic Enzyme On Rumen Fermentation, Digestion, Metabolism And Performance Of Lactating Cows

This experiment studied the influence of exogenous fibrolytic enzyme to Rumen fermentation,digestion and metabolism and production performance combining the technical means of in vitro, in situ and in vivo methods, which designed to provide exogenous fibrolytic enzyme production in dairy cattle as well as the efficient use of diets formulated to provide a reasonable basis for scientific theories.In experiment 1, three cows have been selected, all of them with the similar age, the similar body weight and a good body condition, and a permanent rumen fistula fitted in them during the mid-and late lactation, which collected rumen fluid for in vitro batch culture fermentation for screening cellulase and hemi-cellulose enzyme portfolio and add appropriate volume of the best. The results showed that the enzyme combinationâ… (A1 and B1) was the best, then the enzyme combinationâ…¡(A1 and B2). The best concentration of enzyme combinationâ… andâ…¡enzyme combinations was 0.1%.In experiment 2, three cows have been selected, all of them with the similar age, the similar body weight and a good body condition, and a permanent rumen fistula fitted in them, which applied pre-and post-self-control test methods and were carried out in three batches. In the first phase, their diet has not been administered enzyme ( control group), respectively, in the second (Testâ… ) and three (Testâ…¡) phase, their basic die was administered the combination of enzymes and enzyme combinationsâ… â…¡, with 0.1% of diet feeding, each lasting 20 days, in which consisted of 15 days pre-feeding period and the sampling period of 2 to 5 days. The influence of exogenous fibrolytic enzymes on fiber Rumen fermentation and digestion and metabolism have been studied systematically. The study includes:(1)study of the impact of exogenous fibrolytic enzyme on ruminal digestion of nutrients, including rumen fermentation, fiber degradation and rumen microbial protein production; (2)the impact of exogenous fibrolytic enzyme on digestion and metabolism of dairy cows. (3) the impact of exogenous fibrolytic enzyme on the indicator of cow blood. The results show that: (1) exogenous fibrolytic enzyme is conducive to rumen fermentation and has increased rumen microbial protein production in dairy cattle (P <0.05) and the digestibility of DM, NDF and ADF (P <0.05 ~ 0.01); (2) exogenous fibrolytic enzyme has significantly improved the apparent digestibility of DM, NDF and ADF (P <0.05 ~ 0.01) as well as the apparent protein digestibility, nitrogen utilization and nitrogen deposition (P <0.05 ~ 0.01). However, it has not had a significant effect on energy balance (P> 0.05). (3) In this experiment, the addition of exogenous fibrolytic enzymes has improved the immune function of cells of dairy cattle, and urea nitrogen in dairy cattle blood has the trend of decline. The indicators relevant to cow blood and fat metabolism are not significantly affected, but those relevant to protein metabolism are remarkably affected.In experiment 3, thirty mid-lactation cows have been selected, all of them with the similar age, the similar body weight and a good body condition, which were grouped three to raise with random,( control group, Testâ… and Testâ…¡) and control group without enzyme, respectively, in groupâ… and groupâ…¡trial diet will be the basis of combination of enzymeâ… and enzymeâ…¡combination by adding 0.1% of diet fed, which used to study enzyme Milk Production and the impact on milk composition.The results showed that the the milk added enzymeafter yield significantly increased (p <0.05), with milk composition did not change obviously (p> 0.05).