The objectives were to: 1) determine the relationship of fecal characteristics with ruminal pH, dry matter intake (DMI) and dry matter digestion and 2) determine the ability of fecal characteristics to predict ruminal pH, DMI, and dry matter digestion. Data were collected in two metabolism studies using eighteen ruminally cannulated steers (n = 36). Each study was a completely randomized design evaluating the effect of a direct-fed microbial during an acidosis challenge. Ruminal pH, DMI, total tract DM digestion and fecal characteristics (fecal pH, washed fecal particle size and mucin casts) were measured for 4 d after the acidosis challenge. Rumen pH was not correlated (P ≥ 0.15) with mucin cast score or mean fecal particle size but was negatively associated with fecal pH (r = -0.42; P < 0.01). Total tract DM digestion was correlated (r ≥ 0.53; P ≤ 0.02) to fecal pH and fecal particle sizes between 1180 and 2360 µm. Dry matter intake was correlated (r ≥ 0.41; P < 0.01) to mean fecal particle size and fecal particle sizes between 2360 and 4750 µm. Multiple regressions were performed with the GLMSELECT procedure of SAS 9.4 using stepwise selection. Ruminal pH was best predicted (r2 = 0.20) by fecal pH and fecal particle size between 1400 and 1700 µm. Total tract DM digestion was best predicted (r2 = 0.92) by fecal pH, mucin cast score, and fecal particle size between 3350 and 1700 µm. Dry matter intake was best predicted (r2 = 0.51) by mean fecal particle size, fecal pH and fecal particle size between 1400 and 850 µm. Overall, results indicated fecal pH was correlated to ruminal pH and total tract DM digestion. Fecal characteristics including washed particle size can also predict total tract DM digestion in feedlot cattle.

中文翻译：

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53 饲养场牛粪便特征、瘤胃 pH 值、采食量和消化之间的关系

目的是：1) 确定粪便特征与瘤胃 pH、干物质摄入 (DMI) 和干物质消化的关系；2) 确定粪便特征预测瘤胃 pH、DMI 和干物质消化的能力。使用 18 头瘤胃插管阉牛 (n = 36) 在两项代谢研究中收集数据。每项研究都是一项完全随机的设计，评估直接喂养的微生物在酸中毒挑战期间的影响。在酸中毒攻击后 4 天测量瘤胃 pH、DMI、全道 DM 消化和粪便特征（粪便 pH、洗涤粪便粒径和粘蛋白管型）。瘤胃 pH 值与粘蛋白管型评分或平均粪便粒径无关（P ≥ 0.15），但与粪便 pH 值呈负相关（r = -0.42；P < 0.01）。全道 DM 消化与粪便 pH 值和 1180 至 2360 µm 之间的粪便粒径相关（r ≥ 0.53；P ≤ 0.02）。干物质摄入量与平均粪便粒径和 2360 至 4750 µm 之间的粪便粒径相关（r ≥ 0.41；P < 0.01）。使用逐步选择的 SAS 9.4 的 GLMSELECT 程序进行多重回归。通过粪便 pH 值和 1400 至 1700 µm 之间的粪便粒径可以最好地预测瘤胃 pH 值 (r2 = 0.20)。粪便 pH 值、粘蛋白铸型评分和 3350 至 1700 µm 之间的粪便颗粒大小可以最好地预测全道 DM 消化 (r2 = 0.92)。通过平均粪便粒径、粪便 pH 值和 1400 至 850 µm 之间的粪便粒径，可以最好地预测干物质摄入量 (r2 = 0.51)。总体而言，结果表明粪便 pH 值与瘤胃 pH 值和全道 DM 消化相关。