Authors: Pelletier, N. Pirog, R. Rasmussen, R.

Article: Comparative life cycle environmental impacts of threee bee production strategies in the Upper Mid-western United States

Journal: Agricultural Systems (2010), doi:10.1016/j.agsy.2010.03.009

The purpose of this research was to perform a life cycle assessment (LCA) on three different types of cattle finishing operations “when weaned calves are either: sent directly to Iowa feedlots; sent to out-of-state small-grain (wheat and other) pastures (backgrounded) then finished in Iowa feedlots; or finished on pasture and hay in Iowa.”  These three methods were compared using four main categories within the LCA analysis: cumulative energy use, ecological footprint, greenhouse gas emissions and eutrophying emissions.

The modeling required for this type of LCA analysis is inherently complex and multi-faceted.  The conclusions of this paper are potentially controversially and counter-intuitive; therefore a first reaction is often to question the methodological and analysis tools used by the researchers.  This, however, is not my intent in reviewing this paper, for several reasons.  First, the paper is written in a transparent tone, and the authors are forthcoming in highlighting the methodological shortcomings of their approach.  Second, the methodological descriptions seem sound and well-established within the scientific community.  Third, I am not the best qualified person to delve into the fine details of methodological nuance in LCA models.  And finally, it would be counterproductive to attack the methodological underpinnings of this research in order to cast doubt on its conclusions.  Instead, it is more constructive to analyze their conclusions so to better inform our decision making.

A critical set of assessment variables included in the LCA were the energy returned on energy investment ratios, which were evaluated “according to: (a) the amount of human-edible food energy produce relative to the total industrial (human-mediated) energy inputs required; (b) the amount of human-edible food energy produced relative to the amount of human-edible food energy consumed by the cattle; and (c) the amount of gross chemical energy produced relative to the gross energy consumption of cattle in each scenario.”

Some of the study’s conclusions are common sense:

Within impact categories, feed production is the dominant contributor to cumulative energy use as well as the ecological footprint of beef production in both the cow-calf and finishing stages.

 But, as mentioned, some conclusions are counter-intuitive:

On a whole-herd basis, impacts are consistently lowest for the feedlot scenario across impact scenarios.  The background/feedlot herd has the highest cumulative energy demand, greenhouse gas, and eutrophying emissions, but a slightly smaller ecological footprint than the grass–finished herd…

And:

Since…feedlot-finished and backgrounding/feedlot-finished animals in the systems we modelled are 132 kg heavier than the grass-finished cattle…impacts are consistently highest across impact categories for grass-finished beef and lowest for feedlot-finished beef.

 It is also worth taking note of the most energy intensive phase of all three production processes:

the cow-calf phase is the greater contributor to resource use and emissions in beef production…[and] is responsible for approximately 63% of impacts per live-weight kg of beef produced in all three of the finishing scenarios.

Finally, the carbon sequestration benefits of intensive pasture management have the potential to reduce greenhouse gas emissions by 15% when compared to feedlot-finished beef.

The authors include three reasons for their counter-intuitive conclusions

• Production of grass finished beef in the US Upper Midwest relies heavily on hay as a winter feed, the production and transportation of which is energy intensive.
• The managed pastures used for the LCA model are distinct from rangelands, and like hay are energy intensive.
• Large feed throughput volumes associated with forage diets require relatively large pastures, and hence have a larger ecological footprint

It would be a mistake to assume that these models indicate high-efficiency for feedlot beef production.  On the contrary, the EROI data is perhaps the most illuminating aspect of this research.

In the above table, EROI refers to the total energy returned relative to the energy invested.  A value of 100% indicates a 1:1 ratio, for every unit of energy invested 1 unit of energy is returned.  First, one quickly realizes the very poor energy performance of all three systems in regards to industrial and chemical inputs.  Second, one realizes that “returns on human-edible energy investment were an order of magnitude higher for pasture finishing compared to feed-lot finishing…”  The authors attribute this to the heavy reliance of corn and soy in feed-lot finishing operations, which can be used for direct human consumption.

Unfortunately, what the authors miss in their analysis are the agroecological and management implications of their research.  In this study, we are looking at three fragments of a broken agricultural system, one that is driven by a market oblivious to the ecological limitations of Nature.  This research, however, when put into a holistic context, provides us with key insights towards reform.

I offer a series of guidelines for reducing the life cycle impacts of beef production. These guidelines can be useful for any type of holistic planning, be it grazing, financial, land or business planning, especially when looking at the HM sustainability testing question.

• Unless absolutely necessary, grains that can be consumed by humans should never be fed directly to grazing animals.
• The use of industrially produced and transported hay must be minimized; when possible, organically and/or locally produced hay is recommended.
• Planted pastures as currently managed are energy intensive and should be converted to vertically stacked systems.  For more on this, see my interview with Colin Seis.
• Mixed herds are more energy efficient than livestock monocultures.  Chickens, turkeys, sheep, and goats can be incorporated into vertically stacked planted pastures.
• Rangelands are well-suited for meat production because they are limited in their capacity to produce human-edible vegetation.
• The authors “recommend combined dairy and beef systems as a means of reducing the impacts of calf production, since dairy cows produce both milk and calves whereas beef cow/calf herds are maintained for calf production only.”

By no means comprehensive, these holistic guidelines are simple yet game changing.  Their application in our planning will build upon the foundation of Holistic Management as a decision-making framework, and have the potentially to radically reduce the carbon and energy footprint of beef production in the United States.