Nutrient intake and digestibility of cotton gin trash treated with hypochlorite oxidant or extruded.

To determine the effect of hypochlorite oxidant and extrusion on nutrient i ntake and digestibility of gin trash (GT) and compare GT with pelleted cott onseed hull (PCSH), two trials were conducted. Treatments included PCSH, un treated (CONT), predigested with a hypochlorite oxidant (PD), extruded (EXT ) and predigested and extruded (P&E) byproduct. Five Holstein heifers were used in a 5 x 5 Latin square design and fed diets containing 25% GT or PCSH . Dry matter (DM) intake of heifers was not different among treatments but intake of diets containing GT was 17% lower than PCSH. Apparent digestibili ty of DM, OM, and NDF was similar for all treatments; however, ADF digestib ility was lowest for PCSH compared to CONT, PD and P&E. Ruminal NH3-N conce ntration was highest for P&E compared to PCSH, CONT and PD. Extrusion decre ased molar proportions of acetate (A) and increased propionate (P) resultin g in lower A:P ratios. Molar proportions of butyrate was greatest for CONT and P&E and molar proportions of isovalerate was greatest for PCSH and PD. Concentrations of plasma urea-N (PUN) and glucose were not different among treatments. In situ digestibility of DM and NDF was greatest for GT compare d to PCSH. Treatment of GT with the mixed oxidant or extruding the GT did n ot improve DM or NVDF digestibility at 48 and 96 h compared to CONT. All GT treatments were digested equally at 192h. Extrusion improved bulk density of GT by 63% but did not improve DM intake or apparent digestibility. Extru ding the material treated with the mixed oxidant in the current study appea red to eliminate any potential increase in apparent digestibility compared with the PD byproduct. This may in part be attributed to the potential loss of solublized components resulting in increased concentration. of less dig estible fraction in the remaining material.