TALL FESCUE IN KENTUCKY
Garry Lacefield and J. Kenneth Evans, Extension Forage Specialists
Department of Agronomy
Tall fescue (Festuca arundinacea
Schreb.), a long-lived grass with short underground stems, is presently
grown on approximately 5.5 million acres in Kentucky and on approximately
35 million acres in the south central United States. It is a versatile
plant used for livestock feed, lawns, turf and conservation purposes, and
is adapted for a wide range of soil and climatic conditions.
Chemical analyses for forage quality
indicate that tall fescue compares favorably to other transition zone grasses.
Many livestock producers, however, have found animal response from grazing
tall fescue to be erratic and often undesirable. Researchers at the University
of Kentucky College of Agriculture have made and continue to make significant
strides towards solving the forage quality problems of tall fescue.
In 1931, Dr. E.N. Fergus discovered
Kentucky 31 tall fescue, as it was later named, growing on the W.M. Suiter
farm in Menifee County in eastern Kentucky. Dr. Fergus was in Menifee County
judging at a sorghum show when a local man approached him and asked if
he was aware of a good grass that was growing in the county. Dr. Fergus
was taken to the Suiter farm where he observed several fields of this "wonder
grass." One large hillside, protected against erosion and with livestock
grazing on it, was covered with the grass. Although the weather had been
cold, the grass was still green.
Dr. Fergus obtained about a pound of
seed from Mr. Suiter which he seeded on the University of Kentucky Experiment
Station farm in 1932. The seed for the original planting on the farm presumably
had come from a seedsman in Virginia, and a patch of the grass was likely
growing on the farm when Mr. Suiter purchased it in 1887. Since it had
been growing in Menifee County for many years, Dr. Fergus had no doubts
about the plant's climatic adaptation.
Early seedings throughout the state
showed the grass to have a long life and hardy persistence. It was also
noted to be unusually deep-rooted for a cool-season grass. When recognized
as a variety of tall fescue, it was named Kentucky 31 after the year in
which it was discovered. From 1932 to 1939, seedings were made in outlying
soil experimental fields and, in 1939, seed was distributed by W.C. Johnstone
for trials by interested farmers. After testing, this grass was released
in 1942 as the "Kentucky 31" variety. In 1945, it was included in the Kentucky
seed certification program. Kentucky farmers readily accepted the new variety
and seeded vast acreage with it.
The new grass was not without its shortcomings,
which became evident with general farm use. The first shortcoming observed
was its relatively low palatability. In addition, cattle grazing on pure
stands in fields grown for seed occasionally suffered from lameness or
even sloughing off of tails, especially during fall and winter. It appeared
that a toxic substance occasionally developed in the fescue which caused
constriction of the blood vessels in the extremities of the animal. Dr.
Lowell Bush and his associates at the University of Kentucky later found
that an alkaloid (organic toxin) contained in tall fescue reduced the rate
of cellulose digestion in the rumen. Researchers at the UK Agricultural
Experiment Station attacked these problems through plant breeding efforts
under the leadership of Dr. R.C. Buckner who is recognized nationally and
internationally for his work on tall fescue. Dr. Buckner released the varieties
Kenwell in 1965 and Kenhy in 1976. Johnstone, a low endophyte/low alkaloid
variety, was released in 1982. Research in conjunction with Dr. Buckner's
work was conducted by many members of the Departments of Animal Sciences,
Agronomy and Plant Pathology.
Summer syndrome is a term used to denote
poor performance by cattle grazing tall fescue during the summer. It is
characterized by the following symptoms: 1) reduced feed intake, 2) lower
weight gain, 3) lower milk production, 4) rough hair coat, 5) rapid breathing,
6) increased body temperature, 7) increased water consumption, 8) more
time spent in the shade, 9) excessive salivation, 10) greater urine volume,
11) reduced prolactin level, 12) possible reduced reproductive performance,
and 13) nervousness. An endophytic fungus Epichloe typhina (=Acremonium
coenophialum), known for several years to be in tall fescue, was found
by Bacon and his co-workers in Georgia fescue pastures on which cattle
showed the summer syndrome. Drs. Lowell Bush, James Boling and Roger Hemken
and others in the University of Kentucky's Departments of Animal Sciences
and Agronomy have shown this fungus to be associated with the occurrence
of alkaloids in tall fescue.
In controlled experiments at the University
of Kentucky, young cattle exhibited the summer syndrome malady when fed
infected tall fescue seed and hay containing alkaloids. However, cattle
fed non-infected tall fescue seed and hay without the alkaloids remained
healthy. These feeding trials strongly suggest that fungus infection of
the grass and the associated alkaloid levels are important to the summer
University of Kentucky researchers
have shown a drastic effect on forage intake, weight gain and milk production
when a high level of this endophytic fungus is present in the animal diet.
Studies conducted by Dr. Roger Hemken and colleagues have shown a 39 percent
reduction in forage intake and a 37 percent reduction in milk production
during the summer in lactating dairy cows. In addition, cows consuming
fungus-infected fescue lost weight while animals consuming non-infected
fescue gained weight.
Similar results have been shown in
beef cattle grazing studies. University of Kentucky researchers showed
average daily gains for animals fed fescue containing high levels of the
fungus to be 0.81 pounds per day while animals fed fescue containing low
levels of the fungus gained 1.37 pounds per day. Similar responses have
been found in other states. Auburn University researchers showed beef production
per acre was increased 18.5 pounds and average daily gains were increased
by 0.83 pounds per day on fungus-free compared to fungus-infected fescue.
More recent studies by Dr. James Boling at the University of Kentucky showed
a 0.55 pound per day increase in ADG for animals grazing low endophyte
Kentucky 31 compared to infected Ky 31. The same study showed a 0.97 pound
per day increase in ADG for animals grazing Johnstone as compared to infected
Ky 31. Additional studies have shown increased daily gains and intake,
and lower body temperatures of steers consuming fungus-free seed or fungus-free
Growth of the Fungus
The endophytic fungus grows between
the plant cells, overwintering in the perennial parts of the plant. In
the spring, fungus growth closely parallels tiller growth of fescue. The
infected flower panicles produce infected seed. The primary method of transmitting
the fungus is through infected seed.
Spread of the Fungus
A statewide survey was conducted in
1981 of tall fescue samples collected from 200 fields, representing 42
of the 120 Kentucky counties. Results showed 97 percent of the fields to
be infected with the endophyte. The amount of fungal infection in individual
fields was not determined and additional studies are being conducted to
Preliminary data indicate that the
spread of the fungus in fescue fields occurs slowly. Stem samples collected
in 1981 from two adjacent fields established in 1974 indicated limited
movement of the fungus across the border from a fungus-infected field into
the field that had been free of the fungus. Future research will emphasize
the effects of mowing and grazing on the spread of the fungus in tall fescue.
Research at the University of Kentucky,
along with research from other states, has convincingly demonstrated that
the endophytic fungus is creating quality problems in tall fescue. An interdisciplinary
team of University of Kentucky researchers is presently seeking additional
answers to the remaining questions concerning fescue quality. Advancements
have been made in breeding and selection of fungus-free plants. Release
of the Johnstone variety and selection within currently available varieties
will provide seed with low fungus levels for new plantings.
A seed certification program has been
implemented by the Kentucky Seed Improvement Association which will provide
labeling and tagging of seed with low fungus content. Any variety eligible
for seed certification can be certified for fungus level. Standards allow
2 percent fungus in Foundation Seed, 3 percent in Registered and 5 percent
or less in Certified Seed. The University of Kentucky Department of Regulatory
Services is conducting tests on seed for the certification program. At
present, no laboratories are available in Kentucky for testing of plant
material for producers.
Low Fungus Varieties
All Johnstone seed to be sold will
need to be certified and contain acceptable low levels of the fungus. The
Johnstone variety is in the process of initial seed multiplication and
certified seed should be available for planting by September 1985. Limited
amounts of certified Kenhy seed are also presently available which have
been tested and labeled for fungus content.
Treating field plants for the fungus
with systemic fungicides has not been successful to date. Research studies
are continuing in Kentucky and other states to screen additional chemicals
for this purpose. Chemical seed treatment has met with limited success,
but additional research is needed. Researchers have been able to obtain
fungus-free fescue plants by heat treatments of infected seed, chemical
treatment of seed, aging seed and by harvesting seed from fungus-free plants.
Preliminary data suggest the possibility
of destroying fungus-infected fescue stands and replacing them with fungus-free
stands using herbicides and no-till techniques. University of Kentucky
researchers have begun long-term studies to determine the best methods
Sufficient data exist to show that the negative effects on animal performance
created by the fungus and alkaloids can be diluted substantially by the
presence of legumes in the animal diet. Grazing studies conducted by Dr.
Nelson Gay and associates over a 2-year period at the West Kentucky Research
and Education Center at Princeton revealed a benefit of legumes in fungus-free
fescue also. Cattle grazing fungus-free Kenhy gained 1.37 pounds per day
while cattle grazing fungus-free Kenhy that had been renovated with red
clover gained 1.64 pounds per day.
The Tall Fescue Research Program at
the University of Kentucky has resulted in major breakthroughs. We are
possibly near discoveries which can answer some of the questions relating
to fescue quality and perhaps provide solutions to some of the problems.
These recent discoveries could equal or surpass in importance the discovery
and release of Kentucky 31 tall fescue.
Appreciation is extended to the following
University of Kentucky research personnel for supplying information for
this publication: James Boling, R.C. Buckner, Paul Burrus, Lowell Bush,
Nelson Gay, Roger Hemken, James A. Jackson, Mark Johnson and Malcolm Siegel.