“Introduction of supplemental feedstuffs, especially byproducts, to the grazing system represents an alternative management strategy that has been shown to support enhanced animal performance,” Smith says. “The addition of supplemental feedstuffs has been shown to increase carrying capacity of pastures while also increasing the concentration of nutrients in the resulting manure and amount of manure nutrients taken up by the subsequent plant.”

Increasing nutrient provision to the animal also has been shown to offset the amount of soil nutrients taken up by the forage crop, he adds. These results indicate that supplemental feeding of grazing cattle may be a viable option to augment or replace pasture fertilization.

“In my doctoral work at Texas A&M, we were trying to find the optimum level (i.e., the least amount) of supplement that would increase cattle weight gains on pasture without the cost of gain exceeding the value of gain,” Smith says. “That’s a pretty thin needle to thread, but that has been the goal of most supplementation research over the years, and we have identified some pretty good systems to address the objectives.”

He has noticed in those systems, though, that when you exceed the economic threshold — when the cost of gain or supplemental feed exceeds the value of gain — the carrying capacity of the pasture (how many animals the forage could support) increases.

“That, in and of itself, means there are more complex economics at play depending on whether you express gain per animal or per acre,” Smith says. “But I also started to question what the added benefits of more animals could be. Specifically, more animals on pasture means more manure, and more manure means more nutrient return to the system. That was the point I wanted to drill down on, and that is where this research was born.”

The major objectives of the study — to determine the effects of supplemental feeding on animal performance, pasture productivity, economic viability and soil fertility and health — are being addressed through a multilocation, multiyear feeding trial at the Experiment Station’s Black Belt Research and Extension Center in Marion Junction and at the Tennessee Valley Research and Extension Center in Belle Mina.

“Across the grazing season, we are measuring animal body weight, soil nutrient status, manure distribution and soil biological activity,” he says. “We also have partnered with an economist at Mississippi State University to put dollar values to the system.”

Some producers might already be using similar systems and not be aware of it, Smith says.

“Offering supplemental feed is nothing new to the world of cattle production,” he says. “However, the discussion has always been focused on providing the limiting nutrient or focusing on the cost of gain. This research shifts the narrative so we can start modifying these systems to focus on the entire pasture ecosystem rather than each finite element.”

Smith says the next questions he is addressing in his research include:

• Does the system change depending on the type of supplemental feed selected?
• Can we increase a certain fertilizer element in the feed to target soil fertility?
• Are there feed additives that would make manure minerals available for plant uptake more quickly?

“This producer-forward line of research questioning has a lot of potential, and I am looking forward to getting boots on the ground for years to come in ground-truthing some of these ‘academic’ questions,” he says.

Ultimately, identifying a nutritional response to the current fertilizer crisis could reduce cost of gain by up to 56% while potentially cutting fertilizer input costs by $24 per hectare, Smith says. This would increase profitability for the 91.9 million head of beef cattle in the United States, especially the 38.5 million head located in the southeastern United States that are raised primarily on pasture systems.

Editor’s note: Paul Hollis is a communications specialist with the College of Agriculture and program coordinator and instructor for the Agricultural Communications program. [Lead photo by Auburn University.]

Angus Beef Bulletin EXTRA, Vol. 16, No. 12-B