奶牛日粮颗粒度及其评价方法的比较

Comparison of Dairy Cow's Ration Particle Size and Evaluation Methods

本试验采集北京地区规模化奶牛场的玉米青贮和TMR(Total Mixed Ration)饲料,使用美国宾州颗粒度分级筛(PSPS)和中国农业大学便携式颗粒度分级筛(BX-4)进行筛分,比较两种颗粒度分级筛的异同,同时为我国制定TMR分级标准提供依据。经对比发现,后备牛、干奶前期牛、干奶后期牛、新产牛、高产牛和中低产牛TMR饲料使用两种分级筛进行饲料颗粒度筛分后,第三层筛网和底盘上的饲料比例均有显著性差异(P<0.05),停留在BX-4第三层筛网上的饲料比例小于PSPS,而底盘上的饲料比例则大于PSPS。BX-4每层筛网的圆形平面不会留有死角,使分级筛比PSPS更易筛分完全,整体的圆台形设计又便于携带。试验研究发现,BX-4分级筛的结构和水平移动模式更倾向于使颗粒度小的饲料通过有限的水平移动次数通过筛孔,使得筛分过程更加充分,从而更好地衡量饲料颗粒度。本试验结果为我国制定TMR分级标准提供了第一手信息。

This study was conducted by collecting a large number of corn silage and TMR feed from large-scale dairy farms in Bejing to compare the differences of Penn State Particle Size Separator （PSPS） with the BX-4 particle size separator, and laso provide the database for TMR grading standards in China. The test used PSPS and BX-4（Invention Patent：Protable type particle size separator and its application method, Patent No. ： ZL 2006 1 0089264.4） separate the same feed samples, respectively. By calculating the feed ratio remaining in all the four sieves to identify the differences of the two kinds of particle size separators. According to the comparison, we found that after separating the replacement heifer, far away dry cow, close up dry cow, fesh cow, high-producing cow and low yield cow＇s TMR with two kinds of separators, the feed ratio of the third seieve and the bottom of the separators have significantly differences （P〈0.05）, the feed ratio on the third sieve of the BX-4 is smaller than PSPS, and the feed ratio on the bottom of the BX-4 is much more than PSPS.The round surface of the sieve has not dead angle and make the separate procedure more complete.BX-4 of the circular-shaped design, it makes BX-4 easier to carry than the PSPS. The experiment found that, BX-4＇ s structure and shaking pattern for particle size separation makes the small particle size feed are easier to through the sieve pore in a limited number of times by shaking the sieves and makes the shaking process more sufficiency. This study based on the large number of sampling and analyzing data from large-scale dary farms in Beijing can provide the first-hand information for China TMR grading standard.