WESTERN PRODUCER — Grass-fed beef production has seen a groundswell of support as public concerns over climate change have increased.
This consumer ideology helped drive retail sales of fresh grass-fed beef in the United States from $17 million in 2012 to $272 million in 2016 and experts predict niche market and grass-fed beef sales will increase globally by $40 billion through 2025.
The growing demand has raised concerns, says Sarah Klopatek, a researcher with the animal science department at the University of California, Davis.
“Although grass-fed beef is perceived as more environmentally friendly than grain-fed, research to accurately address this perception is severely lacking,” she said. “The rising demand has raised many producers’ and consumers’ concerns regarding quality, economic viability and environmental impacts.”
Klopatek and her team undertook a large-scale research study that examined performance, carcass quality, financial outcomes and environmental impacts of four California-based grass-fed and grain-fed beef systems.
“We weren’t looking for a fight about grass-fed versus other approaches,” she said. “We did the study to find answers and help producers accurately handle the tough questions their neighbours and friends are asking about grain or grass-fed beef.”
In the trial, which ran from July 2018 to late 2019, 22 Angus and Angus cross steer calves were designated per group. The treatments included:
- (CON) conventional steers stocked on pasture and feedyard finished for 128 days.
- (GF20) steers grass-fed for 20 months.
- (GR45) steers grass-fed for 20 months with a 45-day grain finish.
- (GF25) steers grass-fed for 25 months.
Klopatek said the main goal was to use a whole systems approach to determine the relationship between economic feasibility, product quality and environmental impact with various grass-fed processes.
“We did it holistically and in opposition to other studies, all our beef was sold into the supply chain. That’s what made this project unique. It wasn’t something done in a tiny lab setting.”
To mimic naturally raised grass-fed harvesting, no added hormones were used and animals needing antibiotic treatments were removed from the study. In total, 68 steers were harvested.
All groups grazed summer and fall irrigated pastures until the CON treatment entered the UC Davis feedyard. Through the winter of 2018 and spring of 2019, the GF20, GR45 and GF25 groups rotationally grazed foothills rangeland, with the GR45 cattle joining the CON unit. Pasture and feedyard samples were continuously analyzed to maintain optimal diets.
During processing, all carcasses were handled in identical fashion and assigned USDA quality and yield grades.
To help determine environmental impacts, carbon dioxide, methane and nitrous oxide emissions from transportation and on-site sources such as manure, enteric, fuel combustion and upstream industrial processes were accounted for in GHG impact calculations.
Animal water intake, irrigation of crops and pastures and feedyard water were calculated with the assistance of feedyard managers and a University of California analysis group.
Notable trial findings included:
- CON steers finished with the highest harvest, hot carcass weights (HCW) and dressing percentages (DP) while the GF20 steers were the lowest in these categories.
- The GF25 and GR45 groups had negligible differences in harvest and HCW although the GF25’s DP was four percent lower.
- Marbling scores and quality grades were greater for CON compared to all other treatments.
- GF25 and GR45 treatments had comparable marbling and grade scores and were trailed by the GF20 group, which had the lowest numbers.
- The GF25 steers had the largest water footprint followed by the CON.
- GF20 had the lowest water footprint.
- CON steers showed the lowest global warming potential (GWP).
- The GF20 system was 40 percent greater in GWP mainly due to higher enteric methane production combined with decreased harvest weights and dressing percentages.
- The CON treatment was highest in energy levels owing to increased transportation and farming inputs for feedyard rations.
- GF20 cattle had the lowest energy footprint.
For Klopatek, the water outcomes jumped off the page.
“Being born and raised in the west, it’s an odd thing to hear, but I believe water dictates carbon,” she said. “If we don’t have rain, we supplement with hay requiring more carbon. In turn, gains aren’t as good. The balance relates to water dynamics. Most of the answers about sustainability, resources, production and quality point to regions.”
She sees all production methods as system dependent. Those with more rainfall may not have the same carbon footprint as drier regions. Many areas will be in a steady state.
“How do we continue improving carbon footprints when we have drought?”
Examining grass-fed practices at a national level isn’t accurate science because comparing data from Michigan with 127 centimetres of annual rainfall to California with 50 cm doesn’t compute.
Klopatek says the most noticeable aspect of the findings was how each system identified trade-offs between performance and environmental footprints. For example, the global warming potential was higher for grass-fed groups but lower for energy use. For the CON group, the potential was lower but energy use was higher.
Water totals were lowest for GF20, but that group’s land occupation was highest, and it had the lowest quality grades. For animal performance, all units (GF20, GR45, and GF25) resulted in lower dressing percentages, hot carcass weights and quality grades than the CONs.
“Everyone likes black and white, but we wanted producers to have the tools to speak to trade-offs as a more natural part of the conversation,” she said. “They can feel comfortable saying, ‘yes, higher water use showed up here but lower GHGs there, or higher energy there but less land use here.’ There’s more unpredictability in grass-fed than conventional systems. More systems variability means more environmental footprint variability.”
Klopatek says distinctions between grain and grass-fed beef production units develop varying economic, animal performance and environmental trade-offs rather than being absolutes. Grass-fed beef practices aren’t interchangeable and to gain performance and environmental impact accuracy, they should be evaluated on a regional and management strategy basis.
“Diversity is key to resilience and resilience is key to sustainability. … Grain-fed and grass-fed systems can be part of delivering sustainable food,” she says. “Our study illustrated the complexities underpinning beef sustainability. No system resulted in absolute economic, meat quality and environmental superiority.”
