Which variety of fescue to use depends on several factors according to Dirk Philipp, assistant professor and extension specialist in the Department of Animal Science at the University of Arkansas.
• Production strategies – what is the end product? (calves, backgrounded steers, replacement heifers, grass-fed or even grass-finished beef;
• Soil conditions and how long it might take to correct nutrient and pH imbalances before planting
• Pasture layout and paddock sizes; can cattle be rotationally stocked? (this is important especially for novel-endophyte tall fescue varieties, as these are not as insensitive to “abuse” as the “toxic” fescue Kentucky 31); and
• Financial situation of producers; investment of converting large areas to a new forage is costly.
“For many, past experience plays a large part in their forage planting decisions, and if K-31 has worked for them in the past and they are happy with the results, then perhaps that is what they should go back with,” said Nathan Witt, resource conservationist with Missouri’s U.S. Department of Agricultural Natural Resource Conservation Service. “For those that have the opportunity to renovate a field and are looking to make improvements to their cattle weight gains, I would strongly encourage the establishment of a novel endophyte variety.”
It is also important for producers to calculate the profit potential when considering renovation costs. “It is imperative that a spray-smother crop- spray-plant, method be used when establishing improved fescue varieties,” Witt said. “This can be an expensive proposition up front, as well as time consuming, which is why the long-term benefits must be calculated.”
Producers should realize that the endophyte has a symbiotic relationship with fescue, Witt added. “They depend on each other for survival. If the endophyte is removed from the fescue plant, it simply loses the hardy growth and persistent characteristics that the endophyte provides.”
Fescue toxicosis is caused by the small fungus that grows between the cells of the plant and produces ergot-like alkaloids that negatively affect animal performance. “Certainly the most costly effect is the lack of weight gain in grazing animals (university studies have shown a reduced gain by more than 50 percent), but reproductive problems have also been common such as a thick placenta or aborted fetuses,” Witt said. “Also, we have all noticed those cows that, at the onset of pleasant spring weather, will be standing in the pond up to their shoulders when they should be grazing. This is the effect of the elevation of body temperature that the endophyte causes, while at the same time restricting blood flow to the extremities. The result is lameness in the back feet, such as fescue foot, and the loss of the tail switch. Fescue toxicosis is not just reserved for cattle either. Horses, goats and sheep, can be equally or even more sensitive to the negative effects of the endophyte. Hardened placentas, poor conception rates and reduced milk production are common.”
“In general, the old Kentucky-31 appears to be less sensitive to overgrazing, continuous stocking, and perhaps drought than endophyte-free or novel endophyte (NE) fescues,” Philipp said. “Much of it depends on grazing management, and NE varieties leave less room for incorrect grazing management and fertility management.”
