Precision formulation can reduce protein in the diet and in the manure
By Josh McCann
Sustainability has always been a hot topic at the dinner table for beef producers. Most producers want to pass their operation down to the next generation. While it has never been easy, sustaining the land and viability of the beef business still remains a challenge.
At the beef industry and scientific meetings I attend, discussions on sustainability seem ever-present as they color most challenges at hand. While the nature of sustainability is rightfully complex, many conversations in the beef industry return time and again to methane and its contributions to the carbon footprint of cattle production.
Reducing methane could meaningfully decrease the carbon footprint of beef production, but it is not an easy task. Scientists, like myself, have been researching the topic for more than 50 years. Perhaps there may be some lower hanging fruit?
Global estimates assign less than 10% of all greenhouse gas emissions to the livestock industry. Recent analysis done at West Texas A&M and Texas Tech University evaluated the carbon footprint of feedlot production in the United States. Major contributors to the carbon footprint of feedlot production included enteric methane (primarily the rumen) and manure as expected (Crawford et al., 2022). Together, methane and manure accounted for about 50% of the carbon footprint from feedlot production.
While methane normally gets most of the spotlight, the nitrogen in manure can be converted to nitrous oxide, a greenhouse gas even more potent than methane. Critically, nitrous oxide released from manure is directly influenced by nitrogen-rich protein that was undigested by the animal.
Reducing fecal nitrogen can be as simple reducing the crude protein in the diet. However, any dietary change that reduces cattle growth rate will also add more days until slaughter only hurting a sustainability proposition.
Cattle nutritionists can formulate lower protein diets today by using more highly digestible sources of protein or synthetic amino acids. This practice of precision formulation can reduce protein in the diet and in the manure. So what is the current roadblock? Money.
Currently, there is not a sufficient monetary signal to produce more sustainable beef that would allow nutritionists to formulate diets that are more expensive. However, there is a well-worn path in other livestock species.
The biology and nutrition are fairly straightforward despite the fact that this has not been a focus for the beef industry. The tools are in the toolbox, but who will cover the labor charges for the work?
Protein nutrition also impacts methane emissions from cattle indirectly. Age at slaughter is one of the most critical factors at determining the carbon footprint of a production system. The longer an animal lives, the greater their individual carbon footprint will likely be.
Over the years, the beef cattle industry has done a commendable job genetically selecting for cattle that grow faster. However, weaning weights have remained relatively stable, as cow-calf operations have not captured this growth prior to weaning.
Thus, improving protein nutrition prior to weaning may offer an opportunity to increase weight gain at a younger age and reduce the total days needed to finish a steer.
Two strategies that could address the need are creep feeding and early weaning. Changing the date of weaning alone does not alter the time to finish an animal, but it may allow for a more economical means of accelerating growth in young cattle.
The University of Illinois has long practiced early weaning at about 85 days of age in their fall-calving herd in southern Illinois. Admittedly, there are management tradeoffs to this approach.
However, I have to believe the steers will have a lower carbon footprint than average as they reach majority high choice grade at 14 months of age.
The cattle business has never been one size fits all, and I would not expect it to be in the near future. Cattle and ruminants remain an excellent means of converting the original carbon capture technology (plants) into a nutrient dense and low calorie food.
Reducing the carbon footprint of beef production can be done using understood biological processes like protein nutrition.
These days we have no shortage of sustainability signals to improve beef production, it seems like only a matter of time for the economic signals to fall into place.
McCann is an assistant professor in the Animal Sciences Laboratory at University of Illinois at Urbana-Champaign.