Efficiency of Total Collection and Chromic Oxide Techniques in Short-Term Digestion Trials

Abstract

Sixteen lactating cows were maintained in a conventional stanchion barn adapted for total fecal collection by continuous attendants. The conventional 7-day total collection method of determining digestibility was compared with 1- and 3-day total collections; and with chromic oxide methods using three sampling procedures: 1-day and 3-day total collections and a 1-day collection of six rectal grab-samples at four-hour intervals.Dry matter digestion coefficients (with standard deviations) of 65.7±2.3%, 65.2 ±2.7%, and 65.2±3.8%, respectively, were not significantly different for the 7-, 3-, and 1-day total collection periods. Mean coefficients determined with the chromic oxide method utilizing 1-day grab-samples and 3-day total collections were 64.2±4.6 and 64.4±3.3%, respectively. These were comparable to results obtained by total collection; however, coefficients calculated from chromic oxide determined on 1-day total collections were lower (P<1%). Compared to the 7-day total collection method, the relative efficiency of the 3- and 1-day total collection methods were 75 and 38%, respectively. The 3-day, 1-day, and grab-sample chromic oxide procedures were 49, 61, and 26% as efficient. Generally, higher energy and protein digestion coefficients were also obtained by total collection compared to chromic oxide methods.