Determination of Undegradable Intake Protein Digestibility in Forages

Digestibility of undegradable intake protein of smooth bromegrass, birdsfoot trefoil, and heat-treated alfalfa was determined using the mobile nylon bag technique. Undegradable intake protein (UIP) was determined using neutral detergent insoluble protein at 75% of the total mean retention time; 1.82 and 1.71 in June and July for brome and 1.30 and 1.94 in June and July for birdsfoot trefoil. Digestibility (%) of the UIP in brome was 38.6 and 27.1 in June and July and in birdsfoot trefoil 21.1 and 25.1. The UIP (% DM) of alfalfa dried to simulate dehydrated, sun-cured, and fresh alfalfa, was 3.13, 2.10, and 1.84. Digestibility (%) of UIP was highest for dehydrated (46.4) followed by sun-cured (25.6) and fresh alfalfa (14.7). The undegradable intake protein content and digestibility of the UIP of forages is low