Cattle and carcass performance and life cycle assessment of production systems utilizing additive combinations of growth promotant technologies

Authors: WEBB, MEGAN - South Dakota State University; BLOCK, JANNA - North Dakota State University; HARTY, ADELE - South Dakota State University; SALVERSON, ROBIN - South Dakota State University; DALY, RUSSELL - South Dakota State University; JAEGER, JOHN - Kansas State University; UNDERWOOD, KEITH - South Dakota State University; FUNSTON, RICK - University Of Nebraska; PENDELL, DUSTIN - Kansas State University; Rotz, Clarence - Al; OLSON, KENNETH - South Dakota State University; BLAIR, AMANDA - South Dakota State University

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2020
Publication Date: 11/21/2020
Citation: Webb, M.J., Block, J.J., Harty, A.A., Salverson, R.R., Daly, R.F., Jaeger, J.R., Underwood, K.R., Funston, R.N., Pendell, D.P., Rotz, C.A., Olson, K.C., Blair, A.D. 2020. Cattle and carcass performance and life cycle assessment of production systems utilizing additive combinations of growth promotant technologies. Journal of Animal Science. 4(4):1-15. https://doi.org/10.1093/tas/txaa216.
DOI: https://doi.org/10.1093/tas/txaa216

Interpretive Summary: Growth promoting technologies including hormone-based implants, beta-agonists, and antibiotics are known to improve animal productivity resulting in more efficient beef production. However, there is a growing trend for consumer preference toward more natural production practices that do not use these technologies. An extensive experimental and modeling procedure was used to determine the effects of production systems using combinations of growth promoting technology on animal and carcass performance, use of natural resources, and emissions affecting the environment. Use of these technologies were found to effectively increase the production of beef to meet growing global food demand while simultaneously reducing natural resource use and environmental pollutants, but with some reduction in meat quality. Therefore, producers need to balance the use of growth promoting technologies with their management goals for yield, carcass quality, and environmental impacts.

Technical Abstract: The objective of this study was to determine the impact of different beef production systems utilizing additive combinations of growth promotant technologies on animal and carcass performance, and environmental outcomes. Angus ' Simmental crossbred steer calves (n =120) were stratified by birth date, birth weight, dam age, and assigned randomly to 1 of 4 treatments: 1) no technology (NT, control); 2) antibiotic treated (ANT, fed monensin and tylosin); 3) implant treated (IMP, ANT plus administered a series of three implants, and 4) beta-agonist treated (BA, IMP treatment plus fed ractopamine-HCl for the last 30 d prior to harvest). Weaned steers were backgrounded in a drylot and finished in an individual feeding system to collect animal performance data. At harvest, standard carcass measures were collected and USDA Yield Grade (YG) and Quality Grade (QG) were determined. Information from the cow-calf, backgrounding, and finishing phases were used to simulate production systems using the USDA Integrated Farm System Model, which included a partial life cycle assessment of cattle production for greenhouse gas (GHG) emissions, fossil energy use, water use, and reactive N loss. Body weight in suckling, backgrounding and finishing phases as well as hot carcass weight were greater (P < 0.05) for steers that received implants (IMP and BA) than non-implanted steers (NT and ANT). Average daily gain was greater (P < 0.05) for steers that received implants (IMP and BA) than non-implanted steers during the suckling and finishing phases, but no difference (P = 0.232) was detected during the backgrounding phase. Dry matter intake and gain:feed were greater (P < 0.05) for steers that received implants than non-implanted steers during the finishing phase. Steers that received implants responded (P < 0.05) with larger loin muscle area, less kidney pelvic and heart fat, advanced carcass maturity, reduced marbling scores, and a greater percentage of low choice carcasses offset by a lower percentage of prime grading carcasses compared with steers receiving no implants. Treatments did not influence (P > 0.265) yield grade. The life cycle assessment revealed that IMP and BA treatments reduced GHG emissions, energy use, water use, and reactive N loss compared to NT and ANT. Collectively these data suggest that growth promoting technologies increase production and carcass yield while concomitantly reducing carcass quality and environmental impacts.