It is estimated that 7 to 31% of energy and up to 60% of global protein consumption comes from animal products; all strong indicators that livestock plays an important role in the establishment of food security throughout the world. In the United States, beef cattle production is one of the most important agricultural commodities that generates significant revenue and provides a substantial number of jobs throughout the country. However, despite the tremendous value that livestock represents on a global and national scale, concerns about the environmental impact and the sustainability of animal derived foods have increased in recent years. The overarching goal of the present dissertation was to review the literature regarding the role of beef cattle in sustainable agriculture, and to report the results of three studies aimed to reduce the environmental impact of feedlot beef cattle.Chapter one presents a compilation and review of the literature that encompass the role of beef production in sustainable agriculture. The literature review starts broadly with a description of the U.S. beef industry and its different segments. Then, the text delves into the topic of sustainability and how cattle production fits in the framework of sustainable agriculture. Finally, chapter one covers several topics and the most relevant literature on beef cattle’s environmental impact and approaches to mitigate greenhouse gases (GHG) and air pollutants from cattle feeding operations; all of which is related to the three experimental chapters presented later in the document. Chapter two presents the effects of two essential oil (EO) blends on enteric methane emissions and growth performance of feedlot beef steers. The objective of this experiment was to evaluate two EO blends and compared them to a control for their efficacy as feed additives to reduce enteric methane (CH4) emissions from feedlot beef steers. Twenty-four Angus cross steers were used in a randomized complete block design experiment. Steers were blocked by initial body weight (BW) and allocated in 3 pens (8 steers/pen) where treatments were randomly assigned. Treatments were control (CT) receiving a basal feedlot diet, basal diet supplemented with either Agolin at 1 g/animal/day (AG) or Mootral at 23.5 g/animal/day (MT). Emissions of CH4, CO2 and H2 from steers were collected using the GreenFeed machine. Dry matter intake (DMI) was recorded daily using the Roughage Intake Control system. Results showed that the three treatments were similar (P > 0.05) for all gas emissions from steers, including CH4¬. There was a treatment × wk interaction (P = 0.039) for DMI which was not observed when a pairwise comparison was performed for treatment means within each measurement week (P > 0.10). Growth performance of steers was not affected as BW, average daily gain, and feed efficiency were similar across treatments. Cattle in the various treatments were similar on hot carcass weight, dressing percentage, and fat thickness (P > 0.05); however, marbling score of steers receiving the MT treatment tended to decrease (P = 0.066) and the ribeye area of these animals increased (P = 0.014) by 6.22% compared to those receiving the CT treatment. The third chapter of the present dissertation presents the results from an experiment aimed to investigate the effects of three ratios of rumen available protein to microbial crude protein on GHG and ammonia (NH3) emissions from feedlot beef steers. One hundred and twelve Black Angus steers were used in a randomized incomplete block design to evaluate the effects of 3 rumen available protein to microbial crude protein ratios (RAP:MCP) on growth performance, and gaseous emissions from feedlot steers. Steers were blocked by initial BW and randomly assigned to 1 of 3 treatment rations. Steers were fed rations either Deficient (-150 g/hd/d; DEF), Balanced (0 g/hd/d; BAL) or Excess (+150 g/hd/d; EXS) in RAP: MCP. Steers were allocated and housed in cattle pen enclosures (CPE), and treatments diets were delivered daily as a total mixed ration. The present study consisted of two 42-d periods. Orts were collected weekly and BW every 14 d. Gas measurements were obtained daily in sequential order from all CPE. Steers fed the DEF and EXS produced 20% and 13% more CH4 than those fed the BAL ration (P = 0.010). Mean cumulative NH3 emissions increased linearly by treatment with EXS steers emitting up to 52% more NH3 compared to those receiving DEF (P < 0.001). The fourth and final chapter of the present dissertation shows the results from an experiment aimed to evaluate the effects of heat stress mitigation strategies on growth performance, environmental, and economic outcomes of feedlot beef cattle production in a hot climate. In a completely randomized design with 1,560 Bos indicus bulls were used where three shade structure types were utilized. This experiment included live animal data collection, and a partial lifecycle assessment (LCA) using the Integrated Farm System Model (IFSM). The live animal portion of the experiment was done once a year over a two-year period with three pen replications per treatment per year (n = 6 per treatment). Four shade structures used were: conventional shade (SC; steel shade 1.8 m2 of shade/animal), double conventional shade (DS; steel shade 3.6 m2 of shade/animal), dome structures without fans (DSA; 8.5 m2/animal with 98% solar radiation blocked), and domes with fans (DCA; three large sized low-speed fans). Each pen held 65 bulls in an area of 570 m2. Cattle housed under DCA had 22 kg and 20 kg heavier final body BW (P < 0.05) compared to those housed under SC and DS, respectively. Final BW of DCA and DSA cattle were similar (P > 0.10). Average daily gain, feed efficiency, and hot carcass weight were greater (P < 0.05) for cattle housed under DCA compared to cattle housed under the other shade types. Results were extrapolated to the annual feedlot turnover of 209,700 animals, and cattle in DSA and DCA versus SC and DS had 3-8 % reductions in greenhouse gas and ammonia emissions intensities. Compared to SC, DCA increased profitability by $29.66/animal, followed by DSA and DS with profit increases of $5.79 and $8.90/animal, respectively. The livestock industry is keen to the implement air pollution mitigation approaches that are beneficial for environment and the future of the sector. Research such as the three experimental chapters presented within this dissertation show that alternatives to reduce livestock’s environmental impact are possible; however, not all are yet proven to be a universal solution. Future work should focus on finding solutions that offer incentives in form of performance improvements and that are cost effective for producers to implement in their operations.