The effects of extrusion on ruminal digestion and performance of ruminants
Sanders, Kelly James
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The effects of extruded cottonseed and was evaluated to determine if extrusion would alter the nutrient composition (DM, CP, NDF, ADF, total gossypol, TG , free gossypol, FG, and protein solubility, PS), ruminal digestion (dry matter digestibility, (DMD), true dry matter digestibility (TDD), ammonia release, (AR) and in sim nitrogen disappearance ND), body metabolism and animal performance. Whole cottonseed (WCS) and cull cottonseed (CCS) were extruded with an Insta Pro (Model 2000R) extruder at 112, 123 and 135^0 . Samples were dried and ground through a 1 mm screen for CCS and a 2 mm screen for WCS. Crude protein, EE, ash, TG was higher (P < .05) in the CCS. The effects of extrusion on DM, NDF, ADF and PS were dependent on the type of seed and temperature. Dry matter was increased for WCS and decreased for CCS. Neutral detergent fiber and ADF were higher for WCS and NDF decreased as temperature increased while CCS increased as temperature increased. Protein solubility was higher for WCS and CCS was lower for PS due to temperature. In vitro DMD was not changed by extrusion, but TDD was greater for CCS and TDD was decreased by extrusion temperature. Ammonia release was not significantly different between treatments but a trend of decreased AR was found when extruded temperature was increased. No differences were found for body metabolism. No differences were found in lamb performance when lambs were fed cottonseed meal (control) or different levels of extruded WCS (25, 50 ro 100% of the supplemental protein, EWC25, EWC50 or EWCl00, respectively) except that the EWCl00 had lower ADG while EWC25 and EWCl00 had the lowest FE. Lamb performance was numerically increased for EWC50. Average daily gain was increased by 11% and FE was increased by 8%. These data suggest that extruded cotton products can be used in ruminant diets without negative effects.