The Cotton Byproduct (COBY) process, developed at the USDA-ARS Cotton Production and Processing Research Unit in Lubbock, Texas, is a procedure used to add value to cotton gin byproducts (CGB) whereby a gelatinized starch solution is applied prior to extrusion. A metabolism study and two in vitro experiments were performed to determine the effects of the COBY process on in vitro dry matter digestibility (IVDMD), apparent dry matter digestibility (ADD), feed intake (FI), nitrogen balance (NB), and nitrogen retention as a percentage of intake (NRi) and absorption (NRa). Concentrate diets containing a 30% roughage portion of cottonseed hulls (CSH), ground gin byproducts (GGB), COBY with 4 (COBY 4) or 13% (COBY 13) added starch were analyzed via two separate in vitro analyses and used in a metabolism study. Twenty-four crossbred wether lambs were utilized to determine the effects of the experimental diets. In vitro results indicated that CGB were more digestible (P <0.01) than cottonseed hulls. Results of the metabolism study exhibited 6 to 10% higher digestibility values than those obtained during the in vitro studies. The GGB and COBY 4 showed more acceptable NB, NRi, and NRa. Of all variables measured, CSH treatment diets were superior only for feed intake. However, when all variables were simultaneously accounted for, the best overall feeding value was the GGB and COBY 4 treatments. Data obtained from all experiments conducted during this study indicate CGB processed via COBY to be a viable roughage alternative for ruminant animals.