Fescue Toxicosis in Beef Cattle: Understanding and Managing the Problem - Joe Sellers, Iowa State University Extension; Dr. Scott Flynn, Dow AgroSciences, from the 2014 Iowa Cattle Industry Convention, December 8 - 10, 2014, Des Moines IA, USA More presentations at http://www.trufflemedia.com/agmedia/conference/2014-iowa-cattle-industry-convention

1. Fescue Toxicosis
Joe Sellers
(Thanks to Craig Roberts and Steve Barnhart
for material)

2. How is fescue a problem in
Iowa?
• It is moving further north
• It is colder here than in other fescue belt
states
• We have lost a lot of improved non-fescue
pastures (35% less pasture than 2002)
• Increasing spring growth with N makes it
worse

3. Questions I get
• Does clipping stop the problem?
• How long does it effect the cattle after they are
removed from fescue?
• Are some cattle immune to the effects?
• Do some mineral additives eliminate the
problem?
• How do I identify it?

4. Tall Fescue Endophyte Life Cycle
Active
endophyte
fungus
infects new
grass seedling
Fungus enters
the rapidly
elongating
stem tissue
Fungus Mycelium
invades the
developing seed
Grass Vegetative Stage:
Most Active Fungus Growth
in Leaf Sheaths

5. Fescue BMPs
• Keep vegetative
• Introduce legumes
• Careful with N fertilization
• Fescue toxicosis is a health disorder, not
nutritional, but --
• You must meet cow mineral requirements
• Dilute with other feeds, forages
• Renovate with spray/smother/spray

6. Fescue BMPs
• Good for calving pastures
• Hay will have 50% alkaloid level compared
to grazed
• If stockpile, do it from August 1
• Source genetics from herds with fescue
• Mineral additives – some data finds
response, but mixed results

7.  Vasoconstriction (narrowing of blood vessels)
 Fescue foot
 Poor thermoregulation
 Low feed intake
 Low rate of gain
 Dystocia (birthing problems) and poor reproduction
 Aglactia (poor milk production)
Fescue Toxicosis

8. © George Garner

10. 1400
1000
600
Duckett et al., 2001

11. Problems exist even if native
cattle and no visible signs
• Gain and reproductive losses
• Seed heads and stems are worse, but
alkaloids are in all of the plant
• Year to year and seasonal differences

12. 1999 2000
------- lb/d -------
Toxic endopyte 0.73 0.50
Endophyte-free 1.26 1.56
Novel endophyte 1.30 1.54
Steer gains on three
types of fescue

14. 0
200
400
600
800
1,000
April
May
June
July
August
September
October
Ergovaline(µgkg-1DM)
Georgia Missouri South Carolina
Rogers et al., 2011

15. Alkaloid Management!
 In endophyte (replant)
 In plant (fertilizers, seasonal, anatomical)
 In pasture (dilution, rotations)
 In diet (ammoniation, supplementation)

16. Spray Smother Spray Renovation
 Experiment with small acreage
 Plan for fall plant if possible (Sept. 1 for mid-MO)
 If replacing E+ KY31, may clip seed heads in spring
 Also if replacing E+ KY31, “spray-smother-spray”
 Add legumes later (except for BFT)
 15 lb/A drilled; 1/8” deep
 Add N for “pop-up” (30 to 40 lb/A)
Old
Stand
Summer
Annual
New
Stand
spray & plant
Spring Summer Fall
spray & plant
Yield

17. grass only
with rotation
with supplement
with legumes
E+ E-
DailyGain(lb/A)
Incremental Alleviation

18.  Tall fescue
 Smooth bromegrass
 Orchardgrass
 Red clover
 White clover
 Birdsfoot trefoil
Dilute the Field

19.  Nitrogen increases alkaloid concentration
 High nitrogen associated with toxicosis
Nitrogen Fertilizer (lb/acre)
0 60 120
------- Ergovaline (ppb) -------
Leaf 258 306 485
Stem and Sheath 494 561 1,003
Seedhead 895 1,050 1,488
Rottinghaus et al., 1991
Careful Fertilization

20. ?
Roberts et al, 2002

21. Roberts et al, 2009

22. Graze Stockpile Late Winter
© Rob Kallenbach
Kallenbach et al, 2003

23. Grazing stockpile
• Reduces Hay 2390/lbs per cow compared
to dry lot (three year average)
• Stockpile from around August 1 for beef
balance of yield and quality
• Graze cornstalks first, then stockpiled
fescue (quality, less alkaloids in fescue)

24. Stockpiled legume/fescue

25. Pasture management
is important
• www.iowabeefcenter.org
• Joe Sellers, 641-203-1270
• sellers@iastate.edu
• Welcome, Scott Flynn, Dow AgroSciences