Making fescue work for you

Written by Dr. Jim White on .

It's a tough-growing plant; let's capitalize on it

Fescue has done its share of the work to hold soil on Midwest hills. And it’s also knocked some hair off a cow or two over the years. We tend to abuse fescue through grazing and then curse it for lacking the nutrients our cattle need to gain.

But, tall fescue has plant characteristics and nutritive value similar to those of other cool season perennial grasses like orchardgrass and bromegrass. So we’d figure ruminants eating fescue would perform about the same as if they were on the other grasses. In fact, vegetative cool-season grasses have energy and protein levels that would be expected to support splendid animal performance. Yet, when you see the cows in the pond in high summer, and when you dig through research reports and look at field results, it becomes most apparent that animal performance on fescue can swing from being good to being pitiful.

Looking at the equations to predict beef performance on very high quality fescue, (say 14 to 15 percent protein on a dry matter basis with net energy of gain about 40 and NDF in the low 40s), we would figure this type of forage should deliver somewhere around 2 pounds per head of average daily gain to unsupplemented stocker calves. Then we turn them out and they gain something south of zero. They actually lose weight, which is akin to debt in that there is a way to be worse off than broke.

The difference between actual and predicted animal response is usually explained by the fescue being infected with a fungal endophyte. This fungus produces alkaloid compounds that can have negative impacts on animal behavior, physiology and performance. Ergot alkaloids affect the physiology of cattle to cause reduced blood flow, elevation in body temperature and reduced sweating. When high temperatures and humidity arrive the resulting heat stress lowers grazing time and feed intake. Cattle on fescue may also have hair-coat issues along with reduced grazing time and lower dry matter intake. This can be particularly frustrating in that the low animal performance is in spite of the grass having high concentrations of protein and digestible dry matter.

Fescue Foot and other problems

“Fescue foot” or a tail falling off are pretty dramatic signs of problems with fescue. Most of the time, far milder things are seen: calves don’t shed their winter coats, increased body temperature, increased breathing rate, standing in ponds, low feed intake, low average daily gain, reproductive problems (including poor milk and calving problems).

The ergot alkaloids can be held in the body in the fat. And, you’ll see this sometimes through fat necrosis and strange fat metabolism. Likewise body fat can be a reservoir of the alkaloids, triggering a bigger problem when the animal loses weight.

At this time, we think that dealing with fescue and animals comes down to dealing with the amount of ergot alkaloids.

Animal performance is not necessarily related to the laboratory analyses of nutritive value. Sometimes the nutrients the animals get depend on the concentration of nutrients in the feed—and the amount of feed they eat. When voluntary intake declines, higher nutrient concentration helps performance, but you’ll never put on as much gain in that situation as you did when feed intake was also high.

What makes fescue such a persistent and successful plant in this climate is that the endophyte substantially improves the plant’s ability to withstand stress. You pay for that agronomic advantage through reduced calving percentages and reduced gain as the animals consume the ergot alkaloids produced by the endophyte.

On a principally fescue base, stocker calves will at best achieve about a 1.75 average daily gain. On the same pasture, the other end of the response curve will show as negative gain.

Three ways to fix it

First, cattle can be moved from toxic fescue to warm season perennial grass pastures in the late spring or early summer. Such options are: crabgrass, bluestem, big bluestem, indiangrass, switchgrass and, in places, Bermudagrass. Annual warm season grasses would be an option, such as millets or Sudangrasses. Dilution with legumes in the fescue sward is also an option, the legumes used need to be fairly aggressive, red or white clover or lespedeza. The clovers are easily established into existing sods, compatible with tall fescue and able to increase animal gains. Research in several states has shown that addition of clover to infected tall fescue stands can increase steer gains substantially. Adding clover to a toxic tall fescue pasture has been shown to deliver an extra 0.15 pounds of average daily gain to grazing steers. Additionally interseeding clovers has consistently been shown to dilute the ergot alkaloids and enhance performance and physiology.

Second, you can replace some of the toxic fescue in your herd’s diet with concentrate feeds such as Cattle Charge or Trendsetter.

Arkansas researchers (Goetsch et al, 1987-1989) fed supplement at about 0.75 percent of bodyweight and saw average daily gain double compared to cattle on the same fescue that didn’t get the supplemental feed.

{gallery}Sum10/chart:200:200:1:0{/gallery} Third, you can invest in planting “novel” endophyte strains. These fescues contain an endophyte that does not produce the toxic ergot alkaloids. The fescues with beneficial endophytes are developed by first removing the common endophyte and then replacing it with a different endophyte strain. These novel endophytes are the same fungal species as the common endo¬phyte found in infected tall fescue, yet the novel endophytes produce little or no ergot alkaloids. Since these fungal strains do not produce ergot alkaloids, tall fescue cultivars infected with beneficial endophytes are considered nontoxic.

Fescue won’t go away

It is apparent that cattle producers have a number of reasons to like fescue. If the fescue is infected with toxin-producing endophyte, the question then is what to do to minimize the effects of the alkaloids. Field reports are consistent: fescue responds well to management. While most grasses will respond to management, the magnitude of response is greater with fescue. Fescue dry matter yield responds very well to higher levels of fertility. Yes, the ergot alkaloids and toxicity increase as growth rate of fescue increases. If you are pushing your fescue by using heavier stocking rates then you are going to have to maintain soil fertility. It is known that closely grazed fescue is less toxic. Maintaining good body condition on cows can take care of some of the calving rate issues. Providing additional feed as a pasture supplement dilutes infected fescue and improves feed intake and animal performance.

Management from a feed perspective

For rough work, estimate that for every 10 percent infection you have on a fescue pasture, you lose 0.1 pounds of average daily gain.

You need to do something about the toxin load the animals are eating prior to seeing the symptoms.

If I had to use infected fescue, my first preference would be to feed 0.5 percent to 1 percent bodyweight of a complete feed. In the spring and fall, during rapid grass growth, this provides dilution, better protein efficiency, additive effects and trace mineral-vitamin supplementation.

For stockpiled fescue, the alkaloids are lower. For cows, I’d feed a couple to 4 pounds of breeder cubes. I’d used Trendsetter on the calves. If only using a mineral addition, use a mineral balanced for cool-season grass¬es such as Fescue Equalizer with CTC and aggressive levels of vitamin A, zinc and copper. XI mineral would also be a good choice. The product that we have developed specifically for cattle on fescue is Fescue Equalizer Max. It combines several different approaches to the problem, combining seaweed, clays, essential oils, and yeast products.