Doug Gurian-Sherman is a senior scientist in the Food & Environment Program at the Union of Concerned Scientists (UCS) where he focuses on agricultural biotechnology and sustainable agriculture. He holds a doctorate degree in plant pathology from the University of California at Berkeley and conducted post-doctoral research on rice and wheat molecular biology at the U.S. Department of Agriculture laboratory in Albany, California.
From 2004 to 2006, Dr. Gurian-Sherman was senior scientist at the Center for Food Safety in Washington, DC. Previously, he was founding co-director and science director for the biotechnology project at the Center for Science in the Public Interest. He also worked at the U.S. Environmental Protection Agency (EPA) where he was responsible for assessing human health and environmental risks from transgenic plants and microorganisms and developing biotechnology policy. Before joining the EPA, he worked in the Biotechnology Group at the U.S. Patent and Trademark Office. From 2002 to 2005, Dr. Gurian-Sherman served on the Food and Drug Administration's inaugural advisory food biotechnology subcommittee.
Pastures and forage systems are a healthy way to raise livestock with many potential benefits, including long-term sustainability. Doug Gurion-Sherman explains why we are currently stuck in the less beneficial corn and soy system and why investing the resources to develop efficient grass-feeding methods would be a wise choice.
DG – Interviewer Douglas Gayeton
DS – Interviewee Doug Gurion-Sherman
DG: Could you tell me what a CAFO is?
DS: The acronym is often spelled out as Concentrated or Confined Animal Feeding Operations. They are systems where the livestock are kept in very crowded, unhealthy situations and fed a lot of antibiotics. The USDA and EPA have varying definitions of minimum sizes for what constitutes a CAFO for different types of livestock. An aspect that I think is not given adequate attention is the geographic concentration of CAFOs in certain areas of the country. It’s not only that individual CAFOs are getting so large; they’re relatively crowded together in some parts of the country which exacerbates the problems.
DG: The process of raising animals, like cattle, on grass is much different from raising animals in a feedlot. Is a potential solution to addressing some problems for CAFOs and beef production to create a larger market for grass-fed meat products?
DS: Ruminants—livestock that naturally graze on grasses and forage herbaceous plants— would find a pasture or a range in the wild. That’s their natural diet so it’s healthier for them. Ruminants cannot survive in any kind of healthy state for very long on a diet of nothing but what’s called concentrate. This is a diet of mainly corn and some soybeans to add protein, minerals, and vitamins. That will make cows sick after a while and that’s one of the reasons why they’re fed the antibiotics to help try to keep them healthy longer.
The answer in part, is perennial pastures that have grasses, alfalfa or clover. These would generally have a number of environmental benefits as long as they’re not overgrazed. Those crops tend to build soil fertility, which actually pulls carbon out of the atmosphere and puts it into the soil and also prevents erosion. It’s healthier for the animals so they need many fewer doses of antibiotics. We also know that grass-fed animals tend to have less saturated fat and more omega-3 fatty acids, which are generally believed to be more healthful than the omega-6 fatty acids that are more prominent when animals are fed a diet of grain. So these systems have multiple benefits.
There are some potential downsides that need to be considered as part of the equation. Pasture is utilized somewhat less efficiently than grain. The productivity of corn is so high because we’ve been putting tons of research dollars into improving its productivity for a hundred years. Because of that, it may take somewhat more land to raise a unit of beef or a gallon of milk in a grass-fed system than it would the comparable amount from corn.
In terms of global warming gases, because of that lower efficiency, ruminants would generally produce somewhat more methane, which is a potent global warming gas. The calculations to try to sort all of this out are complex and I don’t think we have all the data we need to really have a really clear picture of all these. My educated guess, based on looking at a lot of these data and trying to add it all up, is that overall there are many environmental benefits to pasture.
The benefits outweigh some of the downsides, but I think what’s also very important to understand is that one of the reasons that the corn/soybean system is so efficient is because we have invested billions and billions of dollars over a period of many decades to make that system more productive and more efficient. We’ve done nothing of the kind to make pasture systems more effective.
As an agricultural scientist, I have a huge amount of confidence that if we put enough resources into research to make pasture production more efficient, we would do so by leaps and bounds. It won’t happen overnight, but increases in productivity in pasture crops and feed efficiency are possible.