Nontoxic Fescue Puts On Cattle Gains From Unexpected Summer Grass Growth

   A good grass-growing year helps farmers who are changing from toxic tall fescue to novel-endophyte fescue, say University of Missouri forage specialists.
   Wet weather put the summer slump on hold for cool-season grasses.
   “With plentiful rains in July, fescue remains green and growing,” Craig Roberts told listeners on a weekly MU Extension teleconference. “We’ve not seen this in 15 years.”
   “Producers who killed toxic Kentucky 31 tall fescue and planted a nontoxic variety hit a perfect year,” Roberts says.
   Toxic fescue, which causes heat stress in grazing cattle, brings problems with a high heat index in July.
   Cattle heat stress combines impact of fescue toxin and high daytime temperatures. Stressed cattle stop grazing and head for shade or ponds.
   Cattle grazing novel-endophyte varieties need not deal with the toxin. They just cope with ambient temperatures.
   A cool-down at night helps cattle and grass growth. Temperatures in the 70s are ideal for cool-season grasses.
   Rob Kallenbach, an MU Extension forage specialist who tracks pasture growth, says mixed fescue-legume pastures are doing well across most of Missouri.
   “Our records show 30 to 60 pounds of dry matter growth per day,” Kallenbach says. “That’s about double what we expect.”
   “The rains help,” he adds. “However, daytime temperatures do limit growth.”
   Producers midway in converting from toxic to nontoxic pastures benefit as well. Killing old fescue takes a spray-smother-spray process. Grass herbicide is applied in the spring. That’s followed with a smother crop, such as warm-season Sudan grass, which wipes out missed tillers and soil-bank seed.
   With the rain, smother crops grow well this summer. That provides supplemental grazing during hot months.
   The Alliance for Grassland Renewal gave workshops across the state teaching fescue conversion the last three years.
   “Producers who converted see the benefits,” Roberts says. “Neighbors can see the difference as well.
   Cattle grazing fescue without toxic endophyte get three times the daily gain. “Immediate benefits show after making the replacement.”
   The novel-endophyte fescues – there are several new varieties – perform best in rotational grazing, Roberts says. Cattle should be taken off a new fescue during severe drought and not graze it into the ground.
   A little more management is needed. However, toxic fescue drives cattle away with heat stress and other side effects.
   Another side effect also adds to heat stress. The toxic fescue delays hair shedding. “Some cattle still wear their winter coats in this heat.” Roberts says.
   “Grazing herds definitely prefer novel-endophyte fescue,” he says. The novel endophyte does provide protection for the grass against drought, insects and fungal pests.
   “Years ago, we tried endophyte-free fescue, but that didn’t work. Now we have varieties that are best for herds – and herd owners.” ∆
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