Fescue Management

Written by: Patrick Wall, Area Beef Field Specialist – SE Iowa, Marion County, Extension Office

It appears the recent attention to fescue grass at the ASA Annual Meeting has a few folks discussing the issue. That’s good. However, it’s probably necessary to attack the topic from all angles; the most successful ‘fescue farmers’ are doing that anyway. There are far more ways to deal with the grass than to find your cows a new zip code or disperse the herd for more tolerant genetics. We’ll start at the beginning.


If you, like me, are not a trained forage agronomist, fescue grass can be difficult to identify. I would encourage you to look at color photos online or pick up a forage identification book. Many Extension offices have these on hand. The simplest way to identify the grass is to grab a leaf by the tip and run your fingers along the edges downward towards the base of the leaf. If it feels like a serrated knife, it is likely tall fescue. The kind or species of fescue plant is much more difficult to spot with the naked eye.


There are actually 3 main types of fescue that plant breeders and forage companies have developed over the years: 1.) Endophyte-free varieties, also known as non-toxic fescue, are not detrimental to cattle, but they are also less hearty and tolerant to grazing pressure. These varieties are not persistent in the south.  As you move north, with shorter summers and less pressure from disease, insects, drought, and with deeper soils, they can persist better. If producers want this grass to survive long-term, it should not be overgrazed. 2.) Novel-endophyte varieties were developed by inserting different endophyte strains in to the fescue plant, but since endophytes occur naturally, it’s not a GMO grass! These grasses are more tolerant and aggressive, but also more expensive. 3.) Endophyte-infected varieties are what we most commonly see in pastures…and in road ditches, construction sites, etc. The grass establishes quickly, holds soil well, and persists in a drought, plus the seed is cheap. Many folks refer to this grass as “Kentucky 31,” though several varieties exist.


If you have planted fescue on your farm and are unsure what variety was seeded down, try to find out. The proper management for each type of grass is slightly different. Many pastures thick with toxic tall fescue were never seeded down to the grass by any farmer. Birds, deer and other animals carried the seed in from road ditches and other farms. Other cattle producers may have purchased toxic tall fescue hay and fed it on the pasture, or the cows seeded it down via feces when they were turned out. As a result, many farmers or ranchers don’t know they have the toxic grass; the fescue spread through the pasture over a number of years.


As you move north in the United States, the success of fescue grass dwindles. The old toxic fescue performs well across a wide band of eastern and Midwestern states, and novel varieties also do well unless they are overgrazed.  Given the cost of the seed, overgrazing can be a very expensive mistake. The endophyte-free varieties can thin out from overgrazing, drought, and pests. The further south you go, the less persistent they are because of the long summers and constant pressure from insects and diseases. The novel varieties do a bit better than endophyte-free ones.


More recently, producers have tried to effectively eradicate the toxic grass and replace it with a better variety for their cows. One of the more popular methods is referred to as “Spray-Smother-Spray.” In other words, use chemicals to kill everything including the toxic fescue, plant a smother crop like sorghum-sudan grass, then spray the pasture again to kill any remaining toxic fescue that remained in the seed bank. Weather can make this pretty challenging, there’s an obvious loss in production, and fence rows, steep terrain, and tree groves make it nearly impossible to achieve an adequate kill in some areas. Long story short, toxic tall fescue is likely here to stay.


It is important to note that not all toxic tall fescue has the same level of “infection.” Some fields may have less endophyte than others. The endophyte itself actually helps the plant survive and produces the alkaloids (toxins) that harm the cow. The part of the plant is crucial as well; less endophyte exists in the leaves, much more in the seed head and the stems at the base of the plant. Consequently, mowing the seed head off or keeping the plant in a vegetative state has proven effective in spring pastures. Forcing cows to eat mature fescue plants (in a drought situation or overgrazing) is often when we see problems like missing tail switches, poor reproductive performance, or “fescue foot,” where the feet actually die or freeze off from poor blood circulation.  Ranchers can test their grass or hay for the alkaloid “ergovaline” to get an idea of the toxicity level. Making hay from toxic tall fescue reduces the toxin level by half as sun curing lowers toxin levels.


Inter-seeding legumes like clovers and trefoil has proven effective at diluting tall fescue, offering a better ‘salad’ to the cows consuming forage. It works best if the fescue is grazed down tight or hayed in order to open up the canopy and allow sunlight to help the legumes grow. Remember, legumes produce their own nitrogen, which can reduce fertilizer needs. One common mistake producers make is applying heavy “N” fertilizer to pastures with toxic tall fescue. The fescue grass loves nitrogen and will grow at an alarming rate, smothering out other grasses and legumes in the mix. Nitrogen also feeds the toxins. Good intentions for pasture renovation often have the opposite effect in this scenario.


Rotational grazing can be an effective management tool as well, keeping tall fescue in a vegetative state where cows are just asked to consume the leaf material. If the pasture has been renovated with novel or endophyte-free fescue, allowing ample recovery time will extend the life of the more desirable varieties. Again, if stocking rates are increased and/or drought conditions persist, some of the desired varieties will not likely survive the challenge. Some producers have found that over-stocking pastures during heavy spring growth then relaxing the stocking rate through the summer helps take advantage of the growth pattern of the grass and limits the toxicity level. Many herds will turn stocker cattle on to fescue grass or even wean them later off the cow when grass growth slows in early summer. Obviously, this only works in a fall calving scenario where winter conditions are tolerable or supplemental feed can be offered to meet the animals’ requirements. The increase in popularity of fall calving is a direct result of producers learning to manage toxic tall fescue.


Another successful management tool with toxic fescue grass is stockpiling for winter grazing. If the producer can prevent the grass from producing a seed head, he/she can also take advantage of the substantial fall growth offered by the plant. The toxin levels increase through the early fall, so grazing can be delayed until late winter, when the toxin levels drop again. Keep in mind, when temperatures plummet in the winter months, poor blood circulation to the extremities can have severe consequences. Producers should test winter forages for nutritional levels and presence of toxins. Remember, you’re not spending all that money to cut, rake, bale, transport, and deliver hay to the cows. They do the baling for you and place the nutrients right back on the ground where you need them. Tall fescue does an amazing job of holding protein and feed value in stockpiled form, often exceeding the nutrient requirements of a gestating cow. If the grass is held under a snow pack, it can be tremendous winter feed. Cows can bury their heads in over a foot of snow to consume forage…and gain weight doing it!


Now, on to the cow. Regardless of breed or genetics, producers can do several things to help their herd thrive in a fescue environment. 1.) Acclimation – Cows that are accustomed to toxic fescue, on average, simply do better on the grass…and so do the calves they produce. That’s not to say that cows naïve to the grass cannot adjust, they can. The longer we give them to adjust before the challenges of lactation and rebreeding begin, the better. Much of the drive for the research discussed at the ASA Annual Meeting was to see if genomics can help us identify which cows do it better, regardless of their zip code. 2.) Supplementation – As the word implies, offering cows some better feed in addition to the fescue diet can help. Of course, added labor and feed costs make this a less desirable option for many producers. However, increased conception rates, tighter subsequent calving intervals, heavier weaning weights, and fewer health problems can help offset the added expense. Some commercial minerals also offer additives that can help cows maintain their body temperature and overall immune function. Be sure to follow label instructions enforced by the new Veterinary Feed Directive (VFD) and consult your veterinarian if necessary. 3.) Shade – This may seem quite simple, but allowing a cow to cool her body temperature can help immensely with performance, displaying estrus, first service conception, etc. Adequate water supply can be beneficial as well; any calories a cow burns walking to water are calories she cannot put in to her calf. Likewise, a good blade of grass that’s too far from water likely won’t get consumed.


There are a number of other successful management strategies for toxic tall fescue not described in the article. I would strongly encourage producers to read up on the subject even if you don’t live in the Fescue Belt. I have included a number of resources for you to study at your leisure.











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