Key points 1. 1.Palatability is more than a matter of taste. Palatability depends on feedback The body has built-in wisdom. Feedback changes preferences automatically I never tried it but I don’t like it. Animals try new foods cautiously to avoid poisoning Skin versus gut. Gut defenses protect us from poisoning and skin defenses protect us from physical harm.

PalatabilityPalatability

A New Definition of Palatability Palatability is the relationship between food flavor and feedback from nutrients and toxins, determined by an animal’s physiological condition, a food’s chemical composition, and an animal’s experiences with the food. Palatability is the relationship between food flavor and feedback from nutrients and toxins, determined by an animal’s physiological condition, a food’s chemical composition, and an animal’s experiences with the food.

Nutrients Increase Palatability

If video doesn’t play, insert file Sheep_eat_straw.wmv

Nutrients Increase Palatability Conditioning Group 1 Group 2 Conditioning Group 1 Group 2 odd days apple+water maple+water odd days apple+water maple+water even days maple+nutrient apple+nutrient even days maple+nutrient apple+nutrient Testing : choice between apple and maple Testing : choice between apple and maple Conditioning Group 1 Group 2 Conditioning Group 1 Group 2 odd days apple+water maple+water odd days apple+water maple+water even days maple+nutrient apple+nutrient even days maple+nutrient apple+nutrient Testing : choice between apple and maple Testing : choice between apple and maple

Energy Increases Palatability Energy Increases Palatability Intake of straw, g DayDay

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. 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 - Dave Barry 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. 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 - Dave Barry

Toxins Decrease Palatability

If video doesn’t play, insert file Food_aversion.wmv

Endophyte-Infected Tall Fescue DayDay Intake of Milo, g Control Ergotamine (1.12 mg/kg BW) Ergotamine Dose

Toxins Limit Intake Toxins Limit Intake Intake of oats, g

Intake is Cyclic Larkspur, % of diet

Postingestive Feedback deficit adequate excess deficit adequate excess palatability palatability Nutrients Nutrients energyenergy proteinprotein mineralsminerals Nutrients Nutrients energyenergy proteinprotein mineralsminerals Toxins Toxins alkaloidsalkaloids terpenesterpenes tanninstannins Toxins Toxins alkaloidsalkaloids terpenesterpenes tanninstannins

If video doesn’t play, insert file Feedback_nutrients.wmv

If video doesn’t play, insert file Feedback_toxins.wmv

Changes in preference are automatic Changes in preference are automatic They are not cognitive nor (at times) rational Changes in preference are automatic Changes in preference are automatic They are not cognitive nor (at times) rational

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?

Which is more important feedback or mom?

If video doesn’t play, insert file good lambs go bad.wmv

Feedback vs Mother Feedback vs Mother Bites of Elm by Lambs Day Mom eats + LiCl LiCl Dose Mom eats Mom averse Mom averse + LiCl

How do they discriminate among different foods? But grazing ruminants eat hundreds of different plant species.

Herbivores don’t eat that many foods in a meal 100 species/ha 100 species/ha 5 species = 65% of diet 5 species = 65% of diet 7 species > 10% of diet 7 species > 10% of diet 100 species/ha 100 species/ha 5 species = 65% of diet 5 species = 65% of diet 7 species > 10% of diet 7 species > 10% of diet

Novel-Familiar Dichotomy

Animals sample novel foods Intake of Rice, g DayDay

Lambs sample familiar foods with novel flavors Bites of Elm

Novel Food Video

If video doesn’t play, insert file Novel_foods.wmv

Familiar-Novel Dichotomy Familiar-Novel Dichotomy Food Intake, g DayDay Rye - novel Corn – prior illness AlfalfaAlfalfa BarleyBarley OatsOats LiCl

Novelty is key but other factors play a role: Generalization (Does the food taste like another food?) Generalization (Does the food taste like another food?) Prior experience (Did it make the animal sick in the past?) Prior experience (Did it make the animal sick in the past?) Amount eaten (Did it make up the bulk of the animal’s diet?) Amount eaten (Did it make up the bulk of the animal’s diet?) Timing (What was the last food eaten?) Timing (What was the last food eaten?)

Can herbivores learn to use medicines?

Oxalate Toxicosis Tannin Toxicosis Tannin Toxicosis Grain Acidosis Polyethylene Glycol Polyethylene Glycol Dicalcium Phosphate Dicalcium Phosphate Physiological States Medicines Bentonite

Sheep learn to take their medicine Control – Medicines not paired with illness Treatment- Medicines paired with illness

Making the bad taste good

Polyethylene glycol binds to tannins… …alleviating their aversive postingestive effects

Cattle fed polyethylene glycol… …eat more sericea

PEG Increases Intake and Preference for Sericea Intake of Serecia (kg) Preference for Serecia vs Grass Hay (%) PEG PEG no PEG no PEG

Cattle trained to eat a variety of weeds…

... by reducing novelty and providing positive feedback

1. Know your weed Nutrients Toxins Nutrient/Toxin Interactions

2. Use the right animals Young Female Healthy Manageable Number and Temperament

3. Build on how animals learn Reduce the fear of new things Make the unfamiliar seem familiar

4. Test animals in trial pastures Small Contains a variety of forages

Making the Good Taste Bad

Training to Avoid Vineyards Orchards Forest Plantations Poisonous Plants (not feasible in most cases)

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. Don’t mix trained animals with animals that eat the target plant.

The Skin and Gut Defense Systems

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

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

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

A field of barley

Neural Convergence

The Wisdom of the Body!

Skin and gut defenses operate on different time Skin Skin milliseconds to seconds Skin Skin milliseconds to seconds Gut Gut minutes to hours minutes to hours Gut Gut minutes to hours minutes to hours

Why do animals overingest poisonous plants?

Plant Issues Toxin doesn’t cause nausea. Toxin doesn’t cause nausea. Toxin has no distinct flavor or toxin levels not paired with changes in flavor. Toxin has no distinct flavor or toxin levels not paired with changes in flavor. Plant Issues Toxin doesn’t cause nausea. Toxin doesn’t cause nausea. Toxin has no distinct flavor or toxin levels not paired with changes in flavor. Toxin has no distinct flavor or toxin levels not paired with changes in flavor.

New places with familiar toxic plants. New places with familiar toxic plants. Stress Stress Starving animals onto a new food. Starving animals onto a new food. New places with familiar toxic plants. New places with familiar toxic plants. Stress Stress Starving animals onto a new food. Starving animals onto a new food. We Set Animals Up For Failure

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 don’t 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.