Research Update: The USDA-ARS-Conservation and Production Research Laboratory, Bushland, Texas

Authors: Cole, Noel; Hales Paxton, Kristin; Todd, Richard

Submitted to: Proceeding of Plains Nutrition Council Symposium
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2011
Publication Date: 4/14/2011
Citation: Cole, N.A., Hales, K.E., Todd, R.W. 2011. Research Update: The USDA-ARS-Conservation and Production Research Laboratory, Bushland, Texas. In: Proceeding of 2011 Plains Nutrition Council Spring Conference, April 14-15, 2011, San Antonio, Texas. p. 64-72.

Interpretive Summary: The Plains Nutrition Council (PNC) is a group of several hundred beef cattle nutritionists and allied experts whot work in the cattle feeding industry of North America. he membership includes private nutritional consultants, feed company nutritionists, university and government researchers, extension specialists, and representatives from pharmaceutical and feed additive companies. The PNC has an annual meeting each April in San Antonio, Texas. At the conference, experts give talks on topics of interest to the cattle feeding industry. In addition, three scientists give brief reviews of their research over the past four to five years. This manuscript provides a brief summary of beef cattle feeding related research conducted at the USDA-ARS-Conservation and Production Research Laboratory, Bushland, Texas, over the past four years. It summarizes data that has been published in scientific journals, conference proceedings, and as scientific meeting abstracts. Topics covered include: (1) effects of corn processing method and distiller's grain on methane emissions from cattle, (2) ammonia emissions from feedlots, (3) methods to control or decrease ammonia emissions from feedlots, and (4) methane emissions from dairy lagoons.

Technical Abstract: This presentation/manuscript provide a brief summary of beef cattle feeding-related research conducted at the USDA-ARS-Conservation and Production Research Laboratory, Bushland, Texas, over the past four years. It summarizes data that has been published in scientific journals, in symposia and conference proceedings and as abstracts at scientific meetings. Topics included are as follows: (1) Effects of corn processing method and dietary inclusion of wet distiller's grain with solubles on energy metabolism and enteric methane emissions of finishing cattle, (2) Nutrient concentrations and proportions in particle size fractions of steam-flaked corn (SFC) to different bulk densities, (3) Summary of ammonia emissions from commercial beef cattle feedlots determined using nitrogen (N) mass balance or micrometeorology techniques, (4) Nitrogen and phosphorus balance of beef cattle feedyards, (5) Effects of fat, a urease inhibitor, zeolite, and distiller's grains on ammonia emissions from beef cattle feedyards, (6) Nitrogen distribution in pen surface of beef cattle feedyards and effects of urine application, (7) Challenges in using flux chambers to measure ammonia emissions from feedlot pen surfaces and retention ponds, and (8) Methane emissions from a New Mexico dairy lagoon system. Summaries of results were as follows: (1) When fed at similar energy intakes, cattle consuming SFC-based diets produce less enteric CH4 and retain more energy than cattle fed dry-rolled corn (DRC)-based diets; however, dietary inclusion of wet distiller's grains with solubles (WDGS) at 30% of diet DM seems to have little effect on CH4 production and energy metabolism. Finishing cattle fed a DRC-based diet excrete a greater amount of C than cattle fed a SFC-based diet. Inclusion of WDGS at 30% of diet dry matter (DM) increased urinary N excretion; (2) During the steam flaking process certain nutrients such as P and fat become concentrated in the finer particles created during the steam flaking process. If smaller particles are disproportionately under- or over-sampled, flaked corn will appear to differ chemically from the original grain being flaked; (3) ammonia emissions from beef feedyards range from an average of 30% of fed N in the winter to about 56% of fed N during the summer with an annual average of about 48% of fed N; (4) at two commercial feedyards daily N intake averaged 362 lb/1,000 head and daily N retention averaged 51 lb/1000 head. Approximately 311 lb of N was excreted daily per 1,000 head of which 112 lb (36% of excreted) was in feces and 199 lb (64%) was in urine. Approximately 147 lb (41% of N intake) was subsequently captured in manure. Of the N intake, 25% in winter to 58% in summer (mean 44.3%) was apparently lost via volatilization. When metabolizable protein (MP) intake exceeded animal requirements, N volatilization losses increased linearly (r2 = 0.53: P < 0.001). Nitrogen excretion and volatilization losses were affected by diet and season; (5) in one trial zeolite, a urease inhibitor, and fat additions decreased ammonia losses from simulated feedlot surfaces by 51 to 86%; the effects of the NBPT and zeolite appeared to be synergistic. Feeding 25% wet distiller's grains in finishing diets increased dietary protein from 12.2 to 16% and increased per capita ammonia emissions 45% (149 vs. 82 g/head daily); (6) applying synthetic urine to feedlot surface caused a rapid increase in ammonium-N concentrations and pH of the pen surface. These results support the hypothesis that ammonia losses from feedlot pens occur rapidly from urine spots; (7) lab scale studies demonstrated that flux chambers will not give accurate estimates of ammonia flux from pen or lagoon surfaces and that large numbers of samples may be required when using chambers for treatment comparisons; and (8) daily methane flux from dairy lagoons averaged 360 lb/ac. Per capita d