Rory Lewandowski, OSU Extension Educator, Agriculture and Natural Resources
One question that beef producers might be asking regarding stockpiled fescue is; when should stockpiled fescue be utilized? If fescue was last grazed, clipped, or harvested for hay in early August and has been stockpiling since that point, a considerable amount of plant material will have accumulated by the time by the time the growing season ends and plants go dormant. Work done in Ohio suggests that if stockpiling was started in early August with 50 units of nitrogen applied around mid-August, and assuming normal precipitation, it is not unreasonable to accumulate more than a ton and a half of dry matter, in fact, 3500 to3700 pounds/acre could be available. Even without nitrogen fertilization a ton or slightly more dry matter could have accumulated. Most cattlemen I have talked with regarding stockpiled fescue say they like to wait until after a couple of hard frosts before turning cattle in to the fescue because cattle will graze it better. This brings up a question of when to begin grazing stockpiled fescue.
Much of the tall fescue in our area is infected with an endophyte, a fungus that produces a toxic substance known as ergovaline. The endophyte and ergovaline are responsible for the reduced palatability of fescue during the summer months. The fescue toxicosis associated with ergovaline is responsible for elevated body temperatures, restricted blood flow to extremities and poor animal performance. It has been generally assumed that ergovaline doesn't pose a problem in stockpiled fescue, in part because the ergovaline seems to concentrate in seed heads and stockpiled fescue is vegetative. Yet, the fact that cattle don't really eat stockpiled fescue well until after a couple of hard frosts suggest there are still concentrations of ergovaline present in infected fescue that reduce palatability until after frost.
An article published in the Journal of Crop Science, volume 43 in 2003 examined ergovaline levels in stockpiled fescue over two winter seasons in Missouri. Previous research had suggested that ergovaline concentrations of 150 parts per billion (ppb) and higher were associated with symptoms of fescue toxicosis during winter months. This study found that there was a rapid loss of ergovaline after mid-December. In the two years of the study ergovaline levels fell below the 150 ppb level by early January in one of the years and by early February in the other year. Researchers suggested that the rate of ergovaline decrease may be related to temperature and rainfall levels. The year in which ergovaline levels declined the slowest was a warm, dry fall and winter as compared to the year when levels declined quicker. Colder temperatures may be associated with less growth allowing for earlier decomposition of ergovaline and it is thought that ergovaline also may be leached out of the plant with rainfall. The conclusion of the article was that since stockpiled fescue retains dry matter and quality throughout the winter, the best use of infected stockpiled fescue was during the late winter period.
A more recent study published in December of 2007 in the Forage and Grazinglands Plant Management Network examined, among other factors, the total ergot alkaloid (of which ergovaline is a part) concentration or endophyte infected fescue from December to March. This study was repeated over 5 years. The results showed an 81% decrease in the ergot alkaloid concentration from early December until early January. So once again, it appears that if the use endophyte infected stockpiled fescue can be delayed until into January, animal performance may be better.
Regardless of when the cattleman decides to allow cattle to graze stockpiled fescue, how the cattle are allowed to graze will determine how efficiently the grass is used. Cattle turned into a large area with unrestricted access to stockpiled fescue are likely to waste 60 to 70 percent of the forage due to trampling and manure deposition. In other words only 30 to 40% of the stockpiled forage is actually eaten. Grazing studies have shown that by restricting access to no more than a 3 day of forage, utilization can increase to levels in the 65 to 70% range. I've talked to some producers who manage even more intensely, restricting access to a one-day supply and they have bumped utilization up to around 80% or better. Research at the Missouri Forage Systems Research Center compared 14-, 7-, and three-day forage allocation strips on stockpiled tall fescue. Strip grazing on a three-day frequency yielded 40% more grazing days per acre than allocating a 14-day forage supply and produced the same level of animal gain.
A final point to keep in mind while managing the fence for stockpiled forage is that a back fence is not needed since the plant is dormant and not growing. This type of management will also help to reduce the amount of trampling and mud created.
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