| dc.description.abstract | A metabolism trial was conducted using eight crossbred Brahman steers to determine the effect of grain processing on protein solubility and digestibility of sorghum. Sorghum grain evaluated was a commercial hybrid grown under irrigated conditioned in Canyon, Texas. Processing methods evaluated were dry rolling (DR), micronizing (M), reconstitution (R), and steam-flaking (SF). The processed grains comprised 75% of the non-supplemented ration with cottonseed hulls, molasses and mineral comprising the remainder of the ration. Feed intake of the rations was recorded daily and grab samples composited for analysis. Samples of processed grain were stored separately. After a 10 day adjustive period, total feal and urine samples were collected and composited over a 5 day collection period. Processed grain and dried fecal samples were analyzed for soluble nitrogen components by the Landry and Moureaux procedure. Apparent digestibilities of dry matter and nitrogen as well as nitrogen balances were calculated.
Apparent dry matter digestibility was highest in steers fed the reconstituted (75.8%) and similar among the DR (68.8%), M (66.2%) and SF (64.1%) cattle. Apparent nitrogen digestibility and nitrogen balance followed a similar pattern being highest in the cattle fed R grains (32.0% and 10.84 oz/day), respectively.
Processing method affected the percentage distribution of the soluble nitrogen with micronizing decreasing the proportion of nitrogen in fraction I and increasing the proportion in fraction V. All processing methods decreased the proportion of soluble nitrogen in fraction III as compared to the DR control. Moist treatments increased and heat treatments within moisture levels decrease the digestibility of fraction I with R being more digestible than SF (59.9 vs 43.3%) and DR being more digestible than micronized grain (30.1 vs 24.2%), respectively. | en |
