Petit H V, Ivan M, Brisson G J
Département de Zootechnie and Centre de Recherche en Nutrition, Université Laval Québec, Québec, Canada.
J Dairy Sci. 1989 Jan;72(1):123-8. doi: 10.3168/jds.S0022-0302(89)79087-1.
Eight Holstein male calves, each fitted with an ileal reentrant cannula at 7 to 10 d of age, were fed a milk replacer based on low heat skim milk powder with or without an oxalate-NaOH buffer known to prevent curd formation in the abomasum. The calves were used to study the effects of milk clotting on digesta flow at the ileum and apparent digestibility measured by fecal and ileal collection. Patterns of ileal flow of total digesta, DM, N, and fat were similar for the clotting and the nonclotting milk replacers. The apparent digestibility of DM and N was higher when measured by fecal than ileal collection for both milk replacers. Digestibility of DM was higher for the clotting than for the nonclotting milk replacer when measured by ileal collection. Clotting did not affect N digestibility measured by either fecal or ileal collection. The concentration of amino acids differed generally in the ileal digesta compared with concentration in feces. In the ileal digesta, some amino acids showed lower concentrations in the clotting milk replacer fed calves compared with those fed the nonclotting milk replacer. The coefficients of digestibility of each amino acid were similar when measured by either fecal or ileal collection. Clotting had no effect on amino acid digestibility measured by both fecal and ileal collection. The data suggest that fecal collection might indicate higher digestibility as compared with ileal collection and that the absence of milk replacer clotting does not affect ileal flow and digestibility of milk replacer N and fat.
八头荷斯坦雄性犊牛，在7至10日龄时每头都安装了回肠再入式插管，分别饲喂以低热脱脂奶粉为基础的代乳粉，其中一组添加了已知可防止皱胃中凝乳形成的草酸盐 - 氢氧化钠缓冲液，另一组未添加。这些犊牛用于研究凝乳对回肠食糜流动的影响以及通过粪便和回肠收集测定的表观消化率。对于添加和未添加凝乳剂的代乳粉，总食糜、干物质、氮和脂肪的回肠流动模式相似。两种代乳粉通过粪便收集测定的干物质和氮的表观消化率均高于回肠收集测定的结果。通过回肠收集测定时，添加凝乳剂的代乳粉的干物质消化率高于未添加凝乳剂的代乳粉。凝乳对通过粪便或回肠收集测定的氮消化率没有影响。与粪便中的浓度相比，回肠食糜中氨基酸的浓度一般有所不同。在回肠食糜中，与饲喂未添加凝乳剂代乳粉的犊牛相比，饲喂添加凝乳剂代乳粉的犊牛的一些氨基酸浓度较低。通过粪便或回肠收集测定时，每种氨基酸的消化率系数相似。凝乳对通过粪便和回肠收集测定的氨基酸消化率均无影响。数据表明，与回肠收集相比，粪便收集可能显示出更高的消化率，并且代乳粉不凝乳不影响代乳粉氮和脂肪的回肠流动及消化率。
