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.”
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. If you’d like to participate, check with your local Natural Resources Conservation Office.
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.
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.
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.
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!
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.
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.
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.
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.
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