A new, ambitious research initiative should significantly enhance the accuracy of estimating raw feed ingredient carbon footprints in the United States. This, in turn, will enable more precise life-cycle assessments (LCA).
In 2024, the United States National Pork Board (NPB) initiated an ambitious, multi-year effort to better understand the efficiency of nutrient utilisation in pigs, manure, soil and crops. Because feed is the single biggest contributor to pork production’s environmental footprint, understanding how nutrients are utilised in the system leads to more robust, accurate and future-proof Life Cycle Assessments (LCAs) in the pork sector.
Laying the groundwork for producer-led LCAs
In the future, pork producers in the US will be able to gauge their own carbon footprints and this work will be foundational to that, says Dr Chris Hostetler, director of NPB’s animal science division. In the USA, LCAs are not a regulatory requirement, but the NPB wants to encourage their members to complete them. That means NPB needs to make completion easy.
But making it easy for farmers to complete their LCAs takes time, and it also requires expertise in a variety of fields. A consortium of subject matter experts was therefore assembled from 5 institutions representing soil science:
- agronomy,
- economics,
- animal science,
- systems modelling and
- agricultural engineering.
Feed is 70–80% of the production footprint for monogastric animals like pigs and chickens. It’s the area of LCA data with the most uncertainty, but also the area where there’s the most opportunity for pork production to reduce its overall footprint.” — Lara Moody, Ifeeder
Why feed dominates the carbon footprint
“Completing an LCA is very data intensive,” explains Lara Moody, the Ifeeder executive director. She says, “Of course, the more accurate the data in any analysis, the closer to reality the analysis will be. Feed is 70-80% of the production footprint for monogastric animals like pigs and chickens. It’s the area of LCA data with the most uncertainty, but also the area where there’s the most opportunity for pork production to reduce its overall footprint.”
Research is being done all the time to better measure the footprint of feed – to analyse the flow of nutrients from raw ingredients in the feed through their transformation in pig growth, levels in the manure and what happens in the field when that manure is applied. But transport of feed ingredients or whether they are grown on farm (using or not using pig manure, etc.), how crops are grown, where they are processed in some cases, all of this must also be analysed.
The consortium is led by Dr Laura Greiner of Iowa State University, and partners with the Institute for Feed Education & Research (Ifeeder). The institute was established in 2009 by the American Feed Industry Association (AFIA) and its associates to connect private feed firms, academics and government agencies in supporting research and education towards a sustainable feed and pet food supply chain.
Among the actions that a pig farmer might make to lower his operation’s footprint are changing manure storage, processing or field application strategies. With feed, Moody notes that feed manufacturers continue to do their part to further reduce footprints with innovations in ingredient selection and processing to help farmers gain higher feed efficiencies. Farmers can also tweak their feed strategies on the farm.
Where feed efficiency stands now
Dr Mike Tokach, from Kansas State University, has been working on the feed processing and efficiency aspects in this context. He explains that at the farm level, US pig producers already apply phase feeding, split sex feeding and other strategies to increase feed efficiencies and reduce excess nutrient excretion over time.
“The main focus today is on further advancements in precision feeding and the use of enzymes and other additives,” he says. “There are some avenues we don’t use in the US because of our markets and consumer preferences, such as feeding ractopamine or use of immunocastration, but it’s used heavily in Brazil and other places. We may one day use these or other technologies to increase feed efficiency further.”
He adds, “We already use phytase heavily of course, and there’s also ongoing research into other enzymes such as proteases and carbohydrases that can increase feed efficiency in the area of 1-3%. It is not easy measuring this size of differences in the field, which makes using a given enzyme a difficult decision for producers. They need to know how much of a difference it will make, and they weigh that against the cost of the enzyme.”
The next wave of feed improvements
Dr Tokach’s colleague in Kansas, Dr Joel DeRouchey, echoes these thoughts. He says, “We are at the refinement stage now and it’s exciting that there are always new products emerging that are improvements compared to what has come before.”
Returning to the LCA data for feed, Moody explains that the footprints for all individual raw pig feed ingredients used in the US are being updated, and there’s also ongoing discussion about how to best improve raw ingredient datasets. In addition, new footprints are being created for ingredients that didn’t have a footprint. “We’ve made a lot of headway,” says Dr DeRouchey. “We should have these data sets ready next year.”
It’s all about reducing the assumptions that producers have to make in their LCAs and using estimated values. In the long term, feed suppliers will be able to provide their producers with the values for the feed or individual ingredients.” — Dr Mike Tokach, Kansas State University
Corn and soybean
Corn and soybean already have data sets on how much energy it takes to produce them. But in the Global Feed LCA Institute database used for feed ingredient footprints, the current state-level crop data is very outdated, from 2012. In addition, for some ingredients, there has never been state-level data, but only one national number. That must be remedied, says Moody, as there are lots of differences in what is required to produce a crop in one state compared to another. “For example, there are differences in irrigation, fertiliser use and fuel use,” she says. “So, we’ve updated the data sets for each of the top-20 corn and soybean-growing states in a collaboration with the United Soybean Board. We’re also adding state level data sets for distillers grains, soybean meal, hominy, sorghum and wheat middlings.”
Examining distillers grains, which previously had only one number for all of the US, Moody explains that “the footprint to grow the corn and process it is going to be different for Iowa versus Pennsylvania, for example. Overall, to get a state number for distillers grains, we have to look at the energy used to grow the corn in a given state, the energy for transporting that corn to the ethanol plant, the energy used to process that corn into ethanol (with distillers grains as a co-product) and then the individual producer in his LCA can add in how far that ethanol plant is from his farm.”
Where corn, manure and footprints meet
If a pig farmer grows his own corn for pig feed, his LCA may be lower than if his corn goes to ethanol production and he feeds the resulting distillers grains back to his pigs. Also, the more pig manure he can apply to his crops, the lower his LCA will be – and as Dr Tokach says, “a lot of producers are already in a good place with nutrient recycling and minimising their operational footprint through their crop enterprises.”
On the manure handling side, he reports that there are state differences with manure too. Each state has different manure application laws, and there are also some differences in the level of nutrients that can be present in the soil.
Future feed data precision
Turning back to the feed values, Dr Tokach notes that eventually farmers will be able to have numbers for their LCAs that are even more accurate than state-level. “It’s all about reducing the assumptions that producers have to make in their LCAs and using estimated values,” he says. “In the long-term, feed supplier will be able to provide their producers with the values for the feed or individual ingredients.”
