America’s “fescue belt,” named for an exotic grass called tall fescue, dominates the pastureland from Missouri and Arkansas in the west to the coast of the Carolinas in the east. Within that swath, a quarter of the nation’s cows — more than 15 million in all — graze fields that stay green through the winter while the rest of the region’s grasses turn brown and go dormant.
But the fescue these cows are eating is toxic. The animals lose hooves. Parts of their tails and the tips of their ears slough off. For most of the year, they spend any moderately warm day standing in ponds and creeks trying to reduce fevers. They breathe heavily, fail to put on weight, and produce less milk. Some fail to conceive, and some of the calves they do conceive die.
The disorder, fescue toxicosis, costs the livestock industry up to $2 billion a year in lost production. “Fescue toxicity is the most devastating livestock disorder east of the Mississippi,” said Craig Roberts, a forage specialist at the University of Missouri Extension, or MU, and an expert on fescue.
By the early 20th century, decades of timber-cutting and overgrazing had left the ranching region in southern states barren, its nutrient-rich native grasses replaced by a motley assortment of plants that made poor forage. Then, in the 1930s, a University of Kentucky professor spotted an exotic type of fescue growing in the mountains of eastern Kentucky, which seemed to thrive even on exhausted land. Unlike most native grasses, Kentucky-31, as it was called, stayed green and hearty through the winter. Ranchers found the species remarkably resilient and, if not beloved by cattle, edible enough to plant. Over the next 20 years, much of the country’s southern landscape was transformed into a lush, evergreen pasture capable of supporting a robust cattle industry.
As early as the 1950s, however, ranchers began to notice tall fescue’s disturbing effects: One study showed that cattle had to be fenced out of other grasses before they’d touch fescue. When they did eat it, the cows saw only one-sixth of their normal weight gain and lost eight pounds of milk production a day.
Between the cells in fescue grows an endophyte, a fungus living symbiotically inside the grass. The endophyte is what makes the fescue robust against drought and overgrazing, but it’s also what makes it toxic. When scientists engineered a version of fescue without the fungal endophyte, in 1982, its hardiness disappeared and ranchers saw it die out among their winter pastures. Farmers learned to live with the health impacts of the toxic version, and today it remains the primary pasture grass across 37 million acres of farmland.
It’s a longstanding problem, and it’s spreading. Warming temperatures from climate change are now expanding the northern limit of the fescue belt, and the grass is marching into new areas, taking root on disturbed land, such as pastures. Northern Illinois and southern Iowa could already be officially added to the fescue belt, Roberts said, introducing toxicosis to new farming regions.
“It’s becoming not just present but part of their normal pastures,” he said, noting that he increasingly gets calls from farmers in this region who are wondering what to do.
As more farmers find themselves facing the challenges of toxic fescue, there are two strategies emerging to finally solve the decades-old problem, though in diametrically opposed ways. One involves planting a modified version of tall fescue — called “friendly fescue” — in which the toxic endophyte has been replaced by a benign one that still keeps the grass hearty and green all winter. Another would abandon fescue altogether and restore the native grasses and wildflowers that once dominated the region, as well as help revitalize natural carbon sinks and fight climate change.
For a variety of reasons — some economic, some cultural — neither solution has really taken hold with most fescue belt ranchers. But the debate embodies the agricultural industry in the era of climate change: As ecosystems shift and extreme weather makes farming even more precarious, ranchers are facing tough decisions about how to adapt their land use practices. What is best for business, and will that ultimately be what’s best for the land and for the changing climate?
Friendly fescue hit the market in 2000, developed by Pennington Seed Inc. It looks identical to toxic fescue and behaves almost identically, thus requiring little change to the ranching habits of fescue belt farmers over the last 70 years.
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Categories: Kentucky, Education, Livestock, Dairy Cattle