Comparison of microdigestion techniques under range and drylot conditions

Abstract

The nutritive evaluation of range forages often is limited by the size of the forage sample available, by the difficulty of determining both the quantity and quality of the forage eaten, and by the labour and other costs of making total faecal collections in digestion trials under range conditions. Microdigestion techniques utilizing either the nylon bag in the rumen (hereafter referred to as nylon bag in vivo) and artificial rumen techniques (hereafter referred to as in vitro) have been reviewed by Annison & Lewis (1959), Barnett & Reid (1961), and Johnson (1963). Forage evaluation could be greatly simplified if such microdigestion techniques could be utilized under range conditions. Following preliminary studies (Van Dyne, 1962), the research reported in this paper was undertaken to evaluate these techniques under both range drylot conditions in studying the intake and digestion of forages. Other aspects of these trials are reported elsewhere (Van Dyne & Weir, 1964; Van Dyne & Meyer, 1964; Van Dyne & Lofgreen, 1964; Van Dyne & Heady, 1965a, b).

Seasonal Changes in Herbage and Cattle Diets on Sandhill Grassland

“…The same rumen fistulated steer was used in all trials and in each case, trials were conducted while the steer was grazing on the experimental pasture. The basic technique used was similar to that of Van Dyne (1962). The 4 by 10 cm bags were constructed of parachute material.…”

“…The nylon bag procedure underestimated (1 to 3%) the digestibility of forage selected by cattle during June and July and overestimated that selected in September (4 to 6%) and December (2 to 3%). The overestimate of digestion in September may have been due to punctures in bags by seeds and seed heads, which allowed an additional loss of forage (Van Dyne and Weir, 1966). In September, seeds were intact in many grazed plants; and upon removal from the rumen, numerous bags had western wheatgrass seeds stuck into them.…”