NITROGEN SOLUBILITY IN 3 SOLVENTS AND IN-SITU PROTEIN DEGRADABILITY OF RUMINANT FEEDSTUFFS

Feedstuffs commonly fed to ruminants were assayed for nitrogen solubil ity by using McDougall's buffer, 0.02 M sodium hydroxide (NaOH), or 0. 15 M sodium chloride (NaCl) as solvents. In addition, in situ dry matt er and protein disappearance from the same feedstuffs were determined using the nylon bag technique in ruminally cannulated sheep for varyin g times of incubation. The mean effective nitrogen disappearance range d from 235 for maize to 894 g kg(-1) of total N for lupins, and dry ma tter disappearance from 240 for meat and bone meal to 793 g kg(-1) for lupins. Protein solubility was lowest (< 10% of total N) for oilseed by-products and animal and fish by-products, intermediate (15-30% of t otal N) for some cereals and highest (35-45% of total N) for wheat var ieties and plant protein sources. Furthermore, solubility and degradab ility data for various feed proteins are presented which demonstrate t he variability in solubility and degradability of ruminant feedstuffs due to protein type or processing.