Obesity in Horses

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Obesity in Horses

• Created by Heidi Van Buren

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My objective is to show how obesity negatively
affects a horses health in many different ways.
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Why do horses get fat?
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Weight gain occurs when the energy intake exceeds
the energy expended.
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Energy requirements for horses

• The energy requirements for horses are often
  overestimated
• Go to this table to find the energy requirements
  of horses conversion table and enter in a
  weight to see the specific energy requirements
• The information for this table was found in
  Feeding Horses, by Melyni Worth on page 206

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Intake Energy (amount Eaten)
100
Fecal Energy
Digestible Energy (amount absorbed)
(75)
Gaseous Energy
Urinary Energy
Metabolizable Energy (amount usable by the
animal) (70)
Heat Loss digestion metabolism making
wastes gut fermentation
Net Energy (amount actually used by the animal)
(30-60 ) for Maintenance Production
Taken from Dr. McNamaras AS205 lecture on
reptiles
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Carbohydrates

• Ingested carbohydrates must be broken down to
  monosaccharides before they can be absorbed
• Glucose
• Galactose
• Fructose
• Glucose and galactose are dependant on the
  sodium/potassium-ATPase pump for transport

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How is fat digested?

• When lipids enter the gastrointestinal tract
  lipid globules are formed
• Bile salts emulsify the lipid droplets and
  forming smaller droplets, to micelles
• This is so that digestive enzymes have better
  access

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The storage of fat

• The muscle and adipose cells synthesize
  lipoprotein lipase
• Lipoprotein lipase hydrolyses the fat into three
  fatty acids and glycerol
• The fatty acids and glycerol enter the cell and
  reform triacyl glycerols

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What constitutes as a fat horse?
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Description of Body Condition Scores by Dr.
HennekeBCS Description

• 1 Poor Animal extremely emaciated spinous
  processes, ribs, tailhead, tuber coxae
• (hooks), and ischii (pins) projecting
  prominently bone structure of withers,
  shoulders, and
• neck easily noticeable no fatty tissue can be
  felt.
• 2 Very Thin Animal emaciated slight fat covering
  over base of spinous processes
• transverse processes of lumbar vertebrae feel
  rounded spinous process, ribs, tailhead,
• tuber coxae (hooks), and ischii (pins) prominent
  withers, shoulders and neck structure
• faintly discernible.
• 3 Thin Fat buildup about halfway on spinous
  processes transverse processes cannot be
• felt slight fat cover over ribs spinous
  processes and ribs easily discernible tailhead
• prominent, but individual vertebrae cannot be
  identified visually tuber coxae (hooks)
• appear rounded but easily discernible tuber
  ischii (pins) not distinguishable withers,
• shoulders, and neck accentuated.
• 4 Moderately Thin Slight ridge along back faint
  outline of ribs discernible tailhead
• prominence depends on conformation, fat can be
  felt around it tuber coxae not
• discernible withers, shoulder, and neck not
  obviously thin.

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• 5 Moderate Back is flat (no crease or ridge)
  ribs not visually distinguishable but easily
• felt fat around tailhead beginning to feel
  spongy withers appear rounded over spinous
• processes shoulder and neck blend smoothly into
  body.
• 6 Moderately Fleshy May have slight crease down
  back fat over ribs spongy fat around tailhead
  soft fat beginning to be deposited along the
  side of withers, behind shoulders and along the
  side of neck.
• 7 Fleshy May have crease down back individual
  ribs can be felt, but noticeable filling
• between ribs with fat around tailhead soft fat
  deposited along withers, behind shoulders,
• and along neck.
• 8 Fat Crease down back difficult to feel ribs
  fat around tailhead very soft area along
• withers filled with fat area behind shoulder
  filled with fat noticeable thickening of neck
• fat deposited along inner thighs.
• 9 Extremely fat Obvious crease down back patchy
  fat appearing over ribs bulging fat
• around tailhead, along withers, behind shoulders,
  and along neck fat along inner thighs
• may rub together flank filled with fat.

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Fat isnt always bad

• What are the benefits of feeding fat?

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Fat

• Functions of Fat in the diet
• Increases absorption of fat soluble vitamins
• A, D, E, and K
• Enhance palatability of some feeds
• Source of essential fatty acids
• Reduces dustiness
• Source of concentrated energy

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Why feed fat and not more grain?

• Fats and oils contain 2.25 times as much energy
  as carbohydrates
• Excessive grain can lead to
• Colic
• Founder
• Fats can increase muscle glycogen storage

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Diseases associated with obesity

• In young/growing horses

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Epiphysitis

• Definition an inflammation of the growth plates
• Found in foals fed for rapid growth
• Prevention feeding for 80 to 90 of maximum
  growth not 100

www.equine-reproduction.com/.../10977/18664.html
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Angular Limb Deformities

• Definition a leg that deviates from the normal
  plane
• Result of unbalanced growth at a joint
• Treatment often requires surgery

www.canterburyequine.co.nz/detailedservices.html
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Osteochondritis dissecans

• Definition progressive breakdown of cartilage
  that has fragments of cartilage loose
• Found in foals that are fed for faster growth

enews.nieuwskiosk.nl
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Diseases associated with Obesity

• In adult horses

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Insulin resistance

• Even healthy obese horses tend to be insulin
  resistant
• They present with abnormally high insulin
  responses to carbohydrates
• Base levels of insulin are increased
• For more information go to the article
  Evidence-Based Equine Nutrition using science
  direct

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Laminitis

• Laminitis is a painful condition where the lamina
  that hold the hoof wall to the sensitive inner
  structures of the hoof separates
• Varies in severity
• Can be chronic or acute
• Obesity and Insulin Resistance lead to chronic
  laminitis

www.johnthevet.com/anatomy.php
www.bushywood.com/.../laminitis.htm
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Laminitis

• Seen in horses with chronic insulin resistance
  because insulin resistance leads to
• Reduced muscle tone of vascular smooth muscle
• Poor perfusion
• Impaired capillary development and repair
• This means that the hoof isnt getting the blood
  supply it needs
• The lamina are very vascular and without the
  nutrients supplied by the blood, they will die

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Diseases associated with obesity

• In broodmares

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A Study on the difference between a high
Concentrate and a high fiber diet to lactating
mares

• High fiber diet led to a higher fat content in
  the milk, higher protein, higher in all minerals
• The high level of milk fat is very important in
  mares, as they tend to have low milk fat
• The high concentrate diet had an increase in
  lactose in the mares milk
• Follow this link to see the study Voluntary
  Intake, Milk Production and Plasma Metabolites in
  Nursing Mares Fed Two Different Diets

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Cycling problems

• Mares that are obese demonstrate
• Longer intervals between ovulations
• Continuously higher levels of progesterone
• Indicating a persistent corpus luteum
• For breeding farms this data indicates that obese
  mares will take longer to rebreed
• This will take you to the article about Obesity
  in the Mare

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References

• Jurgens, Marshall H., and Kristjan Bregendahl.
  Animal Feeding and Nutrition. 10th ed. Dubuque,
  Iowa Kenall/Hunt, 2007.
• Cunha, Tony J.. Horse Feeding and Nutrition. 2nd
  ed. San Diego Academic Press, 1991.
• Worth, Melyni. Feeding Horses. 1st. North Adams,
  MA Storey Publishing, 2003.
• Briggs, Karen. Equine Nutrition. 1st ed..
  Lexington The Blood-Horse, Inc. , 1998.
• Siegal, Mordecai. UCDavis Book of Horses. 1st
  ed.. New York HarperCollins Publisher, 1996.
• Ralston, Sarah L.. "Evidence-Based Equine
  Nutrition." Veterinary Clinics of North America
  Equine Practice 23(2007) 365-384.

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• Doreau, Michel,Boulot Sylviane, Bauchart
  Dominque, Barlet Jean-Pierre, and Martin-Rosset
  William. "Voluntary Intake, Milk Production, and
  Plasma Metabolites n Nursing Mares Fed two
  Different Diets." The Journal of Nutrition
  122(1992) 992-999.
• Vick, MM, DR Sesions, BA Murphy, EL Kennedy, SE
  Reedy, BP Fitzgerald. "Obesity is associated with
  altered metabolic and reproductive activity in
  the mare." Reproduction, Fertility, and
  Development 18(2006) 609-617.