Assesment and Mitigation of Greenhouse Gases and Air Emissions from Beef Production
- ISBN-10
- 1267240857
- ISBN-13
- 9781267240859
- Language
- English
- Published
- 2011
- Author
- Kimberly Rose Stackhouse
Description
Beef production is a recognized source of greenhouse gas (GHG), volatile organic compound (VOC), and ammonia (NH3) emissions. Greenhouse gas sources include enteric fermentation and manure. Methane (CH4) emanates from the animal through eructation as a by-product of enteric processes during digestion. Nitrous oxide (N2O) is primarily following during manure application to soil. The VOCs, ethanol (EtOH) and methanol (MeOH) are produced during the fermentation of fresh manure and NH3 is produced when urea mixes with urease following excretion. Livestock's contributions to climate change and air quality are a growing public policy concern. Recently, research in this area has begun to quantify gaseous emission sources from beef cattle production systems in an attempt to validate full system models to assign a carbon footprint to beef production. In the present experiment CH4, N2O, and carbon dioxide (CO2) emissions were quantified from industry typical feedlot cattle. Methane and CO2 emissions ranged from 1.99 to 4.18 and 226 to 329 g animal−1 d−1, respectively and differed based on body weight and breed. Nitrous oxide emissions ranged from 11.8 to 17.53 mg animal−1 d−1 and did not differ by animal life stage. After quantifying emissions from industry typical animal types we evaluated a model and simulated a full production system to determine the carbon footprint and NH3 emissions of California beef production. An evaluation of differing production management strategies representative of California beef production resulted in ammonia emissions ranging from 98±13 to 138±16 g/kg HCW and carbon footprints of 10.8±1.4 to 22.9±2.0 kg CO2e/kg HCW. Research to develop mitigation strategies for gaseous emissions has also increased in recent years. Improved animal performance is suggested as one of the most effective mitigation strategies to reduce GHGs, VOCs, and NH3 emissions from livestock production systems per unit of product produced. However, little information exists on the effects of increased animal productivity on the net emission reduction from beef production systems. In the present experiment we evaluated the effect of growth promoting technologies on GHG, VOC, and NH3 emission reduction. The beef industry uses ionophores, antibiotics, growth implants, and [beta]2-adrenergic agonists to improve health and growth performance of cattle. A combination of these technologies were applied to feedlot cattle and resulted in decrease CH4, VOCs, and NH3 emissions. However; N2O was increased. This suggests that growth promoting technologies may not only increase productivity, but also alter microbes in the rumen and increase nitrogen retention in the animal leading to changes in GHG, VOC, and NH3 emissions from beef cattle. These treatments were also applied to simulation of the full production system and resulted in a 7 and 10% reduction in the NH3 emissions and carbon footprint, respectively. The present study provides a better understanding of how application of growth promoting technologies to beef cattle affects GHGs, VOC, and NH3 emissions of per kg of product. The present data will be useful to verify models, confirm mitigation strategies, and enhance GHG emission inventories for enteric fermentation, respiration, and fresh excreta for numerous cattle life stages across the beef industry.
