Stockpiling fescue saves time and money by reducing the need to feed hay.

Fescue, the number one forage in Missouri and across the Fescue Belt, remains popular because of its persistence, resistance to insects and disease, and long growing season. Its waxy cuticle keeps its leaves green while growth slows after mid-October, making it the most suitable forage for stockpiling in Missouri.

However, fescue contains ergovaline, a toxic alkaloid that reduces the health and profitability of cow herds. Losses come from low gains, lost conceptions and heat stress. The toxic alkaloids, produced by an endophyte fungus, constrict blood flow to legs, ears and tails. Fescue fed in winter leads to death. In summer, cattle cannot cool properly.

The cattle industry loses an estimated $1 billion annually to lower calving rates, weaning weights, milk production and finishing gains. Therefore, producers must manage fescue differently than other grasses, says Roberts.

Producers should remove cows from fescue pastures by mid-August, he says. Then, fertilize with low rates of nitrogen. Let the pasture grow. Begin grazing again when hay and pasture run out. Stockpiled fescue is least toxic in late winter.

Toxins peak in spring and fall

Research from several universities shows that tall fescue is as toxic in fall as it is in spring, Roberts says. In Missouri, ergovaline concentrations peak in June and then spike again in October-November.

Stockpiling takes advantage of fescue growth cycles. Fescue, a cool-season grass, has two growing seasons. Most productive growth comes in spring, then fescue goes into low-growth summer slump. When fall rains return, grass grows again. Then, fescue becomes toxic again.

Fall toxins are more difficult to regulate than spring toxins, Roberts says.

“If you want healthy animal production, you must manage alkaloids,” he says. “Health and production problems occur because of these two peaks.”

Use incremental alleviation to reduce toxins

Proper management of tall fescue, which differs from other types of fescue, is critical to herd health and profits.

The only silver bullet for fescue toxicosis is a novel-endophyte tall fescue. But, many people continue growing Kentucky 31 fescue. Roberts advises producers to manage with “incremental alleviation.” In other words, use multiple practices at the same time.

A single practice may provide partial relief, but it will not be enough to prevent health problems in animals. “You must do all at the same time to achieve acceptable performance,” Robert says.

Roberts lists eight common practices to reduce toxins.

1. Dilute pastures

Interseed fescue pastures with legumes such as annual lespedeza, red clover and white clover.

2. Supplement diet

Add corn or other feeds to reduce toxin levels. Corn gluten and other byproduct feeds are common supplements.

3. Rotate to summer

Remove cows from pastures mid-May to early fall.

4. Limit nitrogen

Nitrogen boosts forage yields, but it also feeds the fungus, causing more toxins. Toxin levels and nitrogen needs vary year to year, making it difficult to know how much to apply, says Roberts. Research also shows that nitrogen reduces clover, a legume that can dilute toxins. Applying as little as 35 pounds per acre increases toxins. Studies show that nitrogen applied at 60 pounds per acre raised toxin levels significantly.

5. Clip seedheads

Toxins are hottest in seedheads. They also are heavy in the lowest 2 inches of vegetative leaves and stems, according to research by MU Extension Field Agronomist Sarah Kenyon. In the fall, fescue grows only leaves, not seed stems. Leaves store the toxins.

6. Ammoniate hay

Treat low-quality baled hay with ammonia to reduce toxins, make it more digestible, and improve weight gains and milk production by up to 50%. Toxins in cut hay drop by a third within three weeks and by 50% after six months. Keep in mind that fescue made into silage maintains its toxicity.

7. Graze the stockpile late

Normally, cows graze stockpile first then feed hay after. It is best to reverse this, Roberts says. Stockpile is far less toxic in February and March.

8. Spray

Using low rates of recommended herbicides will reduce seedheads in the spring. This makes the pasture less toxic.

Killing old fescue and reseeding a new variety of novel-endophyte fescue can solve problems with toxic fescue, says Roberts.

New varieties cut losses and improve gains. Roberts and other forage experts across the Fescue Belt teach how to seed new varieties at schools offered by the Alliance for Grassland Renewal. For more information, visit their website.

–This originally appeared in the August 11, 2020, University of Missouri Extension News.