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Forage Quality on Rangelands is Dropping

By   /  July 31, 2017  /  9 Comments

Declining forage quality is costing ranchers almost $2 billion a year, and there’s no sign of the downward trend changing.

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This article comes to us from Adam Russell, of Texas A&M AgriLife. It was edited for style and length. For more on this research you can contact Dr. Jay Angerer.

Declining forage quality is costing ranchers almost $2 billion a year, and there’s no sign of the downward trend changing.

That’s what a new study from Texas A&M says. Nutrient content on unimproved native rangelands, especially protein, is dropping due to increased drought, higher levels of carbon dioxide in the atmosphere, and sustained nutrient loss from grazing. “All have the potential to reduce cattle performance by reducing the nutritional quality of forage,” says researcher Jay Angerer.

Declining quality means cattle have become increasingly stressed for protein over the past two decades, likely reducing cattle weight gain. The research estimates it costs producers an additional $1.9 billion annually to meet the U.S. cattle herd’s protein needs with supplemental feed.

“There are financial implications for producers and eventually the consumer,” he said. “Producers already have enough to worry about, and if their supplemental feed costs go up, their margin shrinks, and that may lead to a decision on whether to stay in the business or get out.”

Manure samples arrive at the Grazing Animal Nutrition Lab at the Texas A&M AgriLife Research and Extension Center in Temple. The manure samples are analyzed to show producers the nutrient quality of their forages. Thousands of samples collected over the past 20 years have shown long-term declines in nutritional value in native forages on America’s grasslands. (Texas A&M AgriLife Extension Service photo by Adam Russell)

The conclusion that forage quality was declining came out of 36,000 manure samples collected from U.S. cattle between 1995 and 2015. Texas A&M’s Grazing Animal Nutrition Lab at the Temple Center uses manure samples as a way to estimate the dietary quality of the producer’s forage, especially looking at crude protein and total digestible nutrients. This information is used to optimize supplemental feeding regimens for the producers.

The look at manure samples collected over a 20-year span showed that digestible organic matter and crude protein quality were declining. Over 20 years, available crude protein decreased 1 percent which amounts to an average 10-pound loss per head without supplemental feed.

Angerer said the downward trend in nutritional value on rangelands poses a measurable concern for producers and consumers in the future. The U.S. had 86 million cattle that were not on feed, including 27 million calves, in July 2015, according to the study.

Angerer said potential losses depend on the rangeland, the animal’s production stage, growth, lactation, gestation, the season, temperatures and other factors that could increase the amount of supplemental feed to make up for the crude protein losses.

“These aren’t large differences after 20 years, but if that trend continues for 60 years it might get into something that makes a large difference for production capacity,” Angerer said. The reduction in forage quality creates what Angerer and the other researchers labeled a “protein debt.”

The study concluded the protein debt is likely to grow “if the drivers of the reduction of protein in plants cannot be identified and reversed, or adaptation strategies enacted” and could lead to net losses in cattle production.

Enriching native grasslands with nitrogen is discussed in the study, but fertilizing millions of acres would be counterproductive, Angerer said, so producers face higher supplemental feed costs or the cost of establishing improved pastures for grazing.

In 2010, the U.S. Department of Agriculture’s Natural Resources Conservation Service ramped up its conservation stewardship program that provides incentives to producers who participate in the studies.

Angerer said participation in the NRCS program is picking up. Last year, producers turned in 19,000 samples for analysis, with most coming from the Great Plains area. Most participating producers send in six samples per year.

The samples will continue to be analyzed to assist producers’ supplemental feeding programs, added to the long-term forage quality study and held in storage for future research.

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About the author

editor and contributor

Rachel’s interest in sustainable agriculture and grazing has deep roots in the soil. She’s been following that passion around the world, working on an ancient Nabatean farm in the Negev, and with farmers in West Africa’s Niger. After returning to the US, Rachel received her M.S. and Ph.D. in agronomy and soil science from the University of Maryland. For her doctoral research, Rachel spent 3 years working with Maryland dairy farmers using management intensive grazing. She then began her work with grass farmers, a source of joy and a journey of discovery.

9 Comments

  1. Jim Gerrish says:

    I’m a little late coming to the conversation, but I have to agree with some of the other comments that the decline is more likely due to lack of effective grazing management rather than climate change. No, I am not a climate change denier. I have read some of the research regarding elevated CO2 levels resulting in lower protein %. It is real, but the degree of change is what I would call an academic butterfly. It is statistically significant, it is publishable, and a researcher can build a career around such research. In the greater scheme of landscape scale range condition, I think the effect of poor grazing practices on plant community is the overriding cause of the decline in protein availability on the range.

  2. Troy Reinke says:

    Why was there no definitive statement on the suspected causes of this nutrient decline. This study would bear more weight if they had also included research that listed range trends from these sample areas. This nutrient decline is more like a product of overgrazing. Continuous overgrazing of native rangelands removes the palatable, nutrient dense decreaser species from the range sites. This leads to the increaser and invasive species increasing. The average trend on most range sites has been negative, reverting to a state of woody dominated sites with cool season and early successional warm season plants as the predominant forage species. These poorer quality grasses then become the primary forage base by default. Poor condition native rangelands are going to produce a poor quality of forage. It would stand to reason that poor grazing management leads to poor range condition leads to poor nutrient availability leads to poor performing livestock and the need to provide expensive protein supplements.

    • Kathy Voth says:

      Actually there were three causes suggested for the decline – over-grazing, climate change and drought. Also, I’ve been trying to get ahold of the primary researcher so I can provide some additional information like this. So stay tuned!

  3. Jess Jackson Jr says:

    My initial reaction was that this is a grazing management problem rather than climate.

    Poor management overgrazes leguminous species removing this high protein component from the diet.

    I am convinced that mimicking creation where predators keep the herds moving yields better soil-forage-and livestock quality ass each build up from the improved management.

    Also occurs to me that the opposite could be true. Short grazing periods with more mature forage could yield the same research result and cows in the first and second trimester are okay. Last trimester and growing animals need better quality forage. Hmmmmmm.

    • Kathy Voth says:

      As I understand it, Jess, the nutritional quality of C3 grasses is impacted by elevated atmospheric CO2. According to one paper I read, a significant increase in sugars, starch and fructan in the C3 grasses under elevated CO2 was associated with a significant reduction in their protein levels. So it’s a function of the grasses and their reaction to increasing CO2 in our atmosphere that may be contributing to lower forage quality overall. I’ll look for more information on this to share with On Pasture readers.

      • Gary Jones says:

        CO2 is a limiting nutrient, especially for C3 plants that evolved for a higher CO2 concentration. Green houses pump in additional CO2 to mitigate this lack.

        However, easing one limiting nutrient exposes the next limit. Perhaps it’s water, though higher CO2 also reduces water use in C3, or perhaps it’s nitrogen, though N levels in the environment have also increased due to biomass and fossil fuel burning. Other nutrients also matter and can be limiting. No land has a perfect balance of nutrients naturally, and each place is different.

        The total amount of protein has increased, but not as much as energy (carbohydrate and lipids) so the percentages of each nutrient can, perhaps misleadingly, be spun to find a doom scenario. It’s standard practice for researchers to find some gloomy factor to cite, and link to climate, to signal that they are cooperating with the agenda and deserve increased funding. More research is needed; send money, guns and lawyers.

        Graziers can sensibly respond to changing circumstances with grazing management, supplementation, and eventually improved agronomic practice. Switching the mind set from cowboy to grass farmer helps. Rather than just extracting resources from the range, they might find a management model that is more beneficial. They might improve range rather than just hoping to extract a steady amount year after year.

  4. Gene Schriefer says:

    All 36,000 samples showed decline? None were improving?

    Seems like more of grazing management issue to me and N may not be the answer. Added N may burn through the existing organic matter faster.

  5. Scott Brady says:

    An interesting article, but I wonder if the sudden uptick in sampling due to the CSP Program rollout in 2010 affected the results. Is it possible that the decline in forage quality was due to a sudden influx of samples from arid areas that typically have lower quality forage, but where little or no sampling was done prior to 2010? It will be interesting to see where the next 5-10 years takes us.

  6. Chip Hines says:

    Research from Texas A&M is showing improvements in soils with rest/rotation grazing management. Promoting this type management will become more important in solving the problem at the soil level instead of spending money to adjust what the cow eats.

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