Effects Of Dietary CNDF/rNDF Ratio On Development Of Rumen And Intestinal Of Weaned3-6Monthly Male Calves

This objective is composed of three parts of the feeding trial, nylon trail and slaughter test. It is to study the effect of dietary cNDF(concentrated NDF)/rNDF(roughage NDF) ratio on development of weaned3-6monthly Holstein Calves and confer the rumen fermentation pattern and development of the gastrointestinal tract of the weaned calves in this period.The experiment designed with single factor. Twelve3monthly old Holstein creep bull calves were selected and assigned to four groups randomly based on their body weight(110.5±4.9kg) and age(109.6±3.2d). Each group includes three calves. All the calves were fixed with rumen fistula and the experiment period was10weeks. Each Group fed with one different diet. The ratio of cNDF to rNDF on diet of Group Ⅰ, Ⅱ,Ⅲand Ⅳ was0.27,0.38,0.55and0.77. The results showed that:1. The pH value of each group reduced first and then increased, there was no significant difference of each group(P>0.05), Group IV was6.04, Group I was6.43; The ammonia nitrogen concentration of each group increased first and then reduced, Group I was highest and significantly higher than GroupⅢ and Ⅳ(P<0.05), Group I was15.87mg/100mL, GroupIII was10.91mg/100mL; there was no significant difference of Acetic acid, Propionic acid, Butyric acid and total VFA in each group(P>0.05), Acetic acid of Group I was40.02mmol/L, Propionic acid of Group IV was10.06mmol/L, Butyric acid of Group IV was5.97mmol/L, the total VFA of Group Ⅱ was55.04mmol/L.2. Within72hours, the DM effective degradation rate of each group was not significant(P>0.05), Group Ⅳ was55.89%; the CP effective degradation rate of each group was no significant difference (P>0.05), Group IV was48.19%; the NDF and ADF effective degradation rate of each group was extremely significant difference (P<0.01), NDF of Group IV was45.81%, ADF of Group IV was33.47%.3. The effect of different cNDF to rNDF ratio diets on the development of the rumen papilla was not bad. There was no significant difference in the papilla length on rumen ventral location of each group (P>0.05), Group IV was9.17mm, Group I was7.94mm; the papilla width of Group IV was highest on rumen ventral location and significantly higher than Group II and III(P<0.05) and extremely significantly higher Group I (P<0.01), Group IV was4.35mm; the papilla length of Group III was highest on rumen dorsal location and significantly higher than Group Ⅰ (P<0.05), Group Ⅲ was3.69mm; there was no significant difference of the wall thickness on the rumen ventral and dorsal location and the papilla width on the dorsal location of each group(P>0.05).4. On the location of duodenum, the villus length of Group Ⅳ was highest than other groups with extremely significant difference(P<0.01), Group IV was405.12μm; the mucous membrane thickness of Group IV was highest than other groups with extremely significant difference(P<0.01), Group IV was824.64μm; on the location of front of jejunum, the villus length of Group I was363.32μm, the mucous membrane thickness of Group I was648.13μm, was the lowest than other groups with extremely significant difference(P<0.01); on the location of middle of jejunum, the recessus depth of Group IV was176.45μm, and was lowest than other groups with significant difference(P<0.05); the mucous membrane thickness of Group I was753.76μm, was the lowest than other groups with extremely significant difference(P<0.01); on the location of back of jejunum, the villus length of Group III was highest than other groups with extremely significant difference(P<0.01), Group III was481.60μm, the ratio of villus length to recessus depth of Group I was lowest than other groups with significant difference(P<0.05), Group I was1.88.