|dc.description.abstract||With the ever-increasing world population of over 7 billion and subsequent increase in urbanization, it is crucial for the livestock sector of agriculture to move in the direction of sustainability. Appropriate changes in production practices ensure adequate production with fewer resources to meet the needs of the consumer. Multiple improvements within various management categories are essential to increase animal efficiency and economic gain, improved utilization of natural resources and reduce resulting environmental impacts. The National Air Quality Site Assessment Tool (NAQSAT), originally launched in 2010, provides its users the ability to qualitatively assess how effectively producers are mitigating harmful air emissions in site-specific beef, dairy, swine, broiler chicken, laying hen and turkey production facilities. The air emissions deemed to be of the greatest concern were odor, particulate matter (PM), ammonia (NH3), hydrogen sulfide (H2S), methane (CH4) and Volatile Organic Compounds (VOCs). Eight management categories are considered: animal housing, diet, manure handling, storage and application practices, mortality and road management. The tool enables users to run hypothetical scenarios to identify potential unintended consequences of management modification prior to making costly changes. The NAQSAT has since then been reviewed and updated by experts according to the most up-to-date knowledge and research to create version 2.0. The tool has expanded to include the horse species and air emission nitrous oxide (N2O). Following the implementation of the tool, users are directed to potentially applicable NRCS practices pertinent to their management goals within a given management category/emission of concern. Ideally this will guide users to reformed practices for continued sustainability in today's production environment. In order to accommodate this movement towards sustainability, diet modifications to the typical feedlot diet have been explored; 126 corn fed cross-bred steer calves (initial BW 529.5kg ± 10.7) were supplemented a rumen bypass fat during the last 60 days of the finishing period to evaluate its effects on feedlot performance, carcass characteristics and intramuscular fatty acid composition. Steers were blocked by initial, BW 9 head/pen (n = 7 pens / treatment), at the South Eastern Colorado Research Center (SECRC) in Lamar, CO. Pens were randomly assigned one of two treatment groups: 1) a control diet consisting of a regular corn based finishing ration (CON) and 2) rumen bypass fat treatment consisting of the control diet + Megalac-R/head/day (BF). Diets were formulated to be isocaloric and isonitrogenous. Animals were fed twice daily at 110% of the previous daily ad libitum intake. Feed bunks were cleaned and orts were collected weekly. Dry matter content was analyzed and diet samples were collected weekly for proximate analysis. Individual live weights were recorded and blood samples were collected on d -54, -10, 27 and 60 and 61. Feedlot performance and carcass characteristics were assessed (table 2). Initial BW was included in statistical analysis as a covariate. Steers fed the CON diet had a greater level of performance for most of the parameters measured; the CON treatment had greater DMI (10.14kg vs. 8.77kg; P<0.02) and tended to have greater ADG (1.699kg vs. 1.469kg; <P<0.09) (table 2). Final BW was not significantly different between treatment groups (P<0.16). On d 62, steers were transported to a commercial slaughterhouse where carcass characteristics were assessed. Hot carcass weight was not significantly different between treatments (P< 0.19). Marbling score (P<0.04) and quality grade (P<0.02) were greater for steers fed the CON diet than those fed BF. The L. dorsi area tended to be greater (P<0.10) in steers fed CON (87.60cm2) than those fed BF (84.88cm2). Furthermore, laboratory analysis showed that UFA palmitoleic acid (C16:1) and oleic acid (C18:1 c9) had Trt x Time interactions in the blood serum (table 4). At d 60, C16:1 was significantly increased in the CON group whereas C18:1 was significantly increased in the BF treatment (Table 4). These data suggest that rumen bypass fat may be added to finishing diets without significant reduction in final body weight, although there may be modest reductions in marbling and quality scores. More research is needed to elucidate the potential mechanism for these reductions.