Ferreira J J, Noller C H, Keyser R B, Stewart T S
J Dairy Sci. 1980 Jul;63(7):1091-7. doi: 10.3168/jds.S0022-0302(80)83051-7.
Sixteen Holstein heifers and 20 calves were in trials on the effect of 10 and 15% crude protein and .3 and .9% calcium in the diet on fecal pH and consistency and on rate of passage of the liquid phase of digesta. Time of first appearance of polyethylene glycol was an indicator of rate of passage of the liquid phase in the lower tract of the animal. Respective fecal pH and standard errors for heifers and calves increased from 5.79 +/- .03 and 5.78 +/- .03 on low calcium diets to 6.24 +/- .03 and 6.33 +/- .03 on high calcium diets. High protein diets increased fecal pH from 5.89 +/- .03 and 5.97 +/- .03 to 6.13 +/- .03 and 6.14 +/- .03 for heifers and calves. Effects of calcium and protein were additive. Neither dietary protein nor calcium affected consistency of feces or first appearance of polyethylene glycol in feces. Mean first appearances of PEG in feces were 683 +/- 13 min for heifers and 528 +/- 18 min for calves. Small correlations between fecal pH and fecal consistency and between fecal pH and first appearance of polyethylene glycol in feces indicate little or no relationship of fecal pH to these two variables. From variance in the heifer trial, 10 fecal samples are required to estimate fecal pH within +/-.16 pH units with 95% confidence.
16头荷斯坦小母牛和20头犊牛参与了试验，研究日粮中10%和15%的粗蛋白以及0.3%和0.9%的钙对粪便pH值、稠度以及消化液液相通过速率的影响。聚乙二醇首次出现的时间是动物下消化道液相通过速率的一个指标。小母牛和犊牛在低钙日粮时各自的粪便pH值及标准误分别为5.79±0.03和5.78±0.03，在高钙日粮时则升至6.24±0.03和6.33±0.03。高蛋白日粮使小母牛和犊牛的粪便pH值从5.89±0.03和5.97±0.03分别升至6.13±0.03和6.14±0.03。钙和蛋白的影响是相加的。日粮中的蛋白和钙均未影响粪便的稠度或粪便中聚乙二醇的首次出现情况。小母牛粪便中聚乙二醇的平均首次出现时间为683±13分钟，犊牛为528±18分钟。粪便pH值与粪便稠度之间以及粪便pH值与粪便中聚乙二醇首次出现之间的相关性较小，表明粪便pH值与这两个变量之间几乎没有关系。从小母牛试验的方差来看，要在95%的置信度下将粪便pH值估计在±0.16个pH单位范围内，需要10个粪便样本。
