Joe Sellers, Dr. Scott Flynn - Fescue Toxicosis in Beef Cattle: Understanding and Managing the...

Fescue Toxicosis

Joe Sellers(Thanks to Craig Roberts and Steve Barnhart

for material)

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

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?

Tall Fescue Endophyte Life Cycle

Active endophytefungus infects newgrass seedling

Fungus entersthe rapidly elongatingstem tissue

Fungus Myceliuminvades thedeveloping seed

Grass Vegetative Stage:Most Active Fungus Growth in Leaf Sheaths

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

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

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

© George Garner

1400

1000

600

Duckett et al., 2001

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

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

0

200

400

600

800

1,000

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

be

r

Oct

ob

er

Ergo

valin

e (

µg

kg-1

DM

)

Georgia Missouri South Carolina

Rogers et al., 2011

Alkaloid Management!

In endophyte (replant)

In plant (fertilizers, seasonal, anatomical)

In pasture (dilution, rotations)

In diet (ammoniation, supplementation)

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)

OldStand

SummerAnnual

NewStand

spray & plant

Spring Summer Fall

spray & plant

Yiel

d

grass only

with rotation

with supplement

with legumes

E+ E-

Dai

ly G

ain

(lb

/A)

Incremental Alleviation

Tall fescue Smooth bromegrass Orchardgrass Red clover White clover Birdsfoot trefoil

Dilute the Field

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

?

Roberts et al, 2002

Roberts et al, 2009

Graze Stockpile Late Winter

© Rob Kallenbach

Kallenbach et al, 2003

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)

Stockpiled legume/fescue

Pasture management

is important• www.iowabeefcenter.org

• Joe Sellers, 641-203-1270

• sellers@iastate.edu

• Welcome, Scott Flynn, Dow AgroSciences