Principles of Diet Selection

Beth BurrittArea Rangeland Resources Extension Agent

Website: extension.usu.edu/behave

Or why animals eat certain foods

Behavior Depends on

Consequences

ConsequencesBehavior ConsequencesConsequences

ConsequencesBehavior

Most Behaviors are Learned

Sheep Chase Dog

Her parents refused to buy her a horse

Mother Knows Best

1 2 3 4 50

5

10

15

20

25

Day of Exposure

avoids mountain mahogany

Mom eats serviceberry and …

Nu

mb

er o

f b

ites

/lam

bLambs Eat What Mom Eats

and Avoids What She Avoids

. . .even after weaning

1 2 3 4 5 6 70

25

50

75

100

serviceberry

mountain mahogany

62 63 64 65 66 67 680

25

50

75

100

mountain mahogany

serviceberry

%

of

bit

es b

y la

mb

s

Days after weaning

Neurology Structure Physiology

Experience Changes the Body

Experience changes the body• Brain structure and function• Liver function• Nitrogen recycling• Rumen size• Rumen papilla size and number

Foraging Skills

Palatability is more than a

matter of taste

Nutrients Increase Palatability

Toxins Decrease Palatability

Flavor allows animals to discriminate between foods.

Feedback tells the body whether a particular food flavor is useful or harmful.

Flavors apart from feedback are neither palatable or unpalatable

What is the purpose of flavor?

They can’t be that smart.

1. Changes in preferences for foods are automatic.

2. They don’t have to think about them.

3. At times, they are not rational.

Variety is the spice of life

Monotony – Same Flavor

1 2 3 4 50

500

1000

1500

2000

2500

Day

maple

coconut

1 2 3 4 50

500

1000

1500

2000

2500

maple

coconut

Day

Inta

ke (

g)

Preference for Nutrients

PreferenceEnergy ProteinMeal

High Energy

High Protein

Toxins Limit Intake

1 2 3 4 5 6 7 8 90

150

300

450

600

Day

.75% LiCl

0% LiCl

1.5% LiClInta

ke o

f oat

s, g

Most toxins limit intake causing

animals to eat a variety of foods

PoisonousPlants

Plants with Toxins

the fear of anything new

Neophobia -

Animals Sample Novel Foods

1 2 3 4 5 6 7 8 90

100

200

300

400

no

ve

l f

lav

or

Inta

ke (

g)

Day

Beijing fast food

Beijing fast food

Beijing fast food

How does neophobia keep animals safe and help them learn

about new foods?

1 2 3 40

50

100

150

200

250

Inta

ke (

g)

LiCl

Day

Familiar-Novel Dichotomy

Rye – Novel Food

Corn

Alfalfa

Barley

Oats

How do livestock select their diets?

1. with companions2. familiar foods3. foods high in nutrients and

low in toxins4. a variety of foods5. familiar foods that are rare in

the environment

They prefer to eat:

Training Cows to Eat Weeds

. . . by reducing novelty and

providing variety and positive feedback.

Know your weed• Nutrients• Toxins• Nutrient/Toxin Interactions

2. Work with the right animals

• Young• Female• Healthy• Manageable in Number and Temperament

3. Build on how animals learn

• Reduce fear of new things

• Make the unfamiliar seem familiar

4. Test animals in trial pastures

• Small• Provide a variety of forages

Early Experience Matters Most

Same strawDifferent performance

Different experience

Experience Influences Performance

Body weight ** *Body condition ** *Milk production ** -Post-partum interval ** -

Year 1 Year 2 Year 3

Strategic supplementation

improves use of forage and landscapes

• Low moisture blocks (LMB) contain 2 – 4 % moisture.• LMB are available in 125 - 250 lb containers.• LMB (250 lb) only need to be replaced about once every 2 weeks when fed 1 barrel per 25 cows.

Low moisture block (LMB) effectively

increased and focused grazing in moderate terrain.

LMB attracted cows to graze difficult terrain that typically was not used.

Low-moisture block can be placed with an ATV and trailer in steep, rocky terrain

Training is critical for supplement to be an effective tool to improve grazing distribution.

Animals must also know where supplement is located.

The question isn’t: Do animals learn?

They learn everyday.

The question is:Do we as managers want to

bepart of the process?

Website: extension.usu.edu/behave