Key points

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Key points

1. Palatability is more than a matter of taste.
   Palatability depends on feedback.
2. The body has built-in wisdom. Feedback changes
   preferences automatically.
3. I never tried it but I dont like it. Animals try
   new foods cautiously to avoid poisoning.
4. Skin versus gut. Gut defenses protect us from
   poisoning and skin defenses protect us from
   physical harm.

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Palatability
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A New Definition of Palatability

• Palatability is the relationship between food
  flavor and feedback from nutrients and toxins,
  determined by an animals physiological
  condition, a foods chemical composition, and an
  animals experiences with the food.

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Nutrients Increase Palatability
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Sheep_eat_straw.wmv
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Nutrients Increase Palatability
Conditioning Group 1 Group
2 odd days applewater
maplewater even days maplenutrient
applenutrient Testing choice between
apple and maple
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Energy Increases Palatability
Intake of straw, g
Day
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What are calories?

• Calories are little units that measure how
  good a particular food tastes. Fudge, for
  example, has a great many calories, whereas
  celery, which is not really a food at all but a
  member of the plywood family, provided by mother
  nature so that we would have a way to get onion
  dip into our mouths at parties, has none.
• - Dave
  Barry

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Toxins Decrease Palatability
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Food_aversion.wmv
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Endophyte-Infected Tall Fescue
Control
Intake of Milo, g

Ergotamine (1.12 mg/kg BW)
Ergotamine Dose
Day
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Toxins Limit Intake

Intake of oats, g
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Intake is Cyclic

Larkspur, of diet
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Postingestive Feedback

• Nutrients
• energy
• protein
• minerals

• Toxins
• alkaloids
• terpenes
• tannins

palatability
deficit adequate excess
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Feedback_nutrients.wmv
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Feedback_toxins.wmv
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• Changes in preference are automatic
• They are not cognitive nor (at times) rational

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Flavors apart from feedback are neither palatable
or unpalatable
Feedback tells the body whether a particular food
flavor is useful or harmful.
What is the purpose of flavor?
Flavor allows animals to discriminate between
foods.
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Which is more important feedback or mom?
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bad.wmv
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Feedback vs Mother
LiCl Dose
Mom eats LiCl
Mom eats
Bites of Elm by Lambs
Mom averse LiCl
Mom averse
Day
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But grazing ruminants eat hundreds of different
plant species.

• How do they discriminate among different foods?

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Herbivores dont eat that many foods in a meal

• 100 species/ha
• 5 species 65 of diet
• 7 species gt 10 of diet

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Novel-Familiar Dichotomy
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Animals sample novel foods
Intake of Rice, g
Day
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Lambs sample familiar foods with novel flavors
Bites of Elm
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Novel Food Video
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Familiar-Novel Dichotomy
Barley
Oats
Alfalfa
Food Intake, g
Corn prior illness
LiCl
Rye - novel
Day
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Novelty is key but other factors play a role

• Generalization (Does the food taste like another
  food?)
• Prior experience (Did it make the animal sick in
  the past?)
• Amount eaten (Did it make up the bulk of the
  animals diet?)
• Timing (What was the last food eaten?)

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Can herbivores learn to use medicines?
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OxalateToxicosis
Physiological States
Tannin Toxicosis
GrainAcidosis
Medicines
Polyethylene Glycol
Dicalcium Phosphate
Bentonite
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Sheep learn to take their medicine
Control Medicines not paired with illness
Treatment- Medicines paired with illness
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Making the bad taste good
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Polyethylene glycol binds to tannins
alleviating their aversive postingestive effects
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Cattle fed polyethylene glycol
eat more sericea
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PEG Increases Intake and Preference for Sericea
Preference for Serecia vs Grass Hay ()
Intake of Serecia (kg)
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• Cattle trained to eat a variety of weeds

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. . . by reducing novelty and providing positive
feedback
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1. Know your weed

• Nutrients
• Toxins
• Nutrient/Toxin Interactions

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2. Use the right animals

• Young
• Female
• Healthy
• Manageable Number and Temperament

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3. Build on how animals learn

• Reduce the fear of new things
• Make the unfamiliar seem familiar

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4. Test animals in trial pastures

• Small
• Contains a variety of forages

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Making the Good Taste Bad
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Training to Avoid

• Vineyards
• Orchards
• Forest Plantations
• Poisonous Plants
• (not feasible in most cases)

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Training to avoid

• The understory must be familiar
• Only avert to NOVEL FOODS
• Animals must have free access to salt.
• Dose with LiCl after eating novel food.
• Make certain animals have plenty of alternatives
  to eat when grazing areas that contain the target
  plant.
• Dont mix trained animals with animals that eat
  the target plant.

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The Skin and Gut Defense Systems
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Skin and Gut Defenses

• All organisms have evolved coping mechanisms for
  detecting nutrients and protective mechanisms to
  keep from becoming nutrients.
• - John Garcia

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Not all cues are paired with all consequences
Skin - Physical Harm Place Aversion
Gut - Nausea Food aversion
Sight, Hearing, Touch, Smell
Taste, smell
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Skin and Gut Defenses

• When toxicosis occurs after eating black mice,
  hawks avoid black and white mice, but...
• Hawks avoid only black mice if a distinct
  taste is added to black mice.

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A field of barley
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Neural Convergence
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The Wisdom of the Body!
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Skin and gut defenses operate on different time

• Skin
• milliseconds to seconds

• Gut
• minutes to hours

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Why do animals overingest poisonous plants?
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Plant Issues Toxin doesnt cause nausea.
Toxin has no distinct flavor or toxin levels not
paired with changes in flavor.
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We Set Animals Up For Failure

• New places with familiar toxic plants.
• Stress
• Starving animals onto a new food.

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Key points

1. Palatability is more than a matter of taste.
   Palatability depends on feedback.
2. The body has built-in wisdom. Feedback changes
   preferences automatically.
3. I never tried it but I dont like it. Animals try
   new foods cautiously to avoid poisoning.
4. Skin versus gut. Gut defenses protect us from
   poisoning and skin defenses protect us from
   physical harm.