Obesity In Horses

Question 1

Define obesity

Answer 1

A condition where excess body fat has accumulated to the extent that it may have a negative effect on health

Reduced life expectancy and/or increased health problems

Question 2

How can we assess a horse for ‘fatness’ ?

Answer 2

BCS or CNS

Question 3

What areas should you check when performing a BCS ?

Answer 3

Neck -3- flows smoothly into withers

Withers - 3- fat deposits

Back and Loin - 3- level back

Ribs -3 - fat over ribs

Hind Quarters

Question 4

What is CNS?

What would a grade 5 look like?

Answer 4

Cresty Neck Scoring

Crest is so large it permanently droops to one side.

Question 5

What is an issue with BCS?

Answer 5

Gives an indication of generalised adipocity

- may hide REGIONAL ADIPOCITY

Question 6

What breeds are more likely to become obese?

Answer 6

Draught type
Cob type
Native (Dartmoor, exmoor )
welsh

Question 7

What horses are most at risk of obesity?

Answer 7

Described as ‘good doers’

Animals not ridden

Summer vs winter

Question 8

How are horses evolved to use fat stored?

Answer 8

Evolved relying on grass

Gain adipocity during summer and autumn
- Increased POMC secreted by pars intermedia (pituitary)

• Stimulates appetite and adipogenesis

Winter - food scarce, rely on fat stores
-depleted prior to spring and grass growth

Question 9

What husbandry practices can broadly result in obesity?

Answer 9

Excess calories

Physical inactivity

Question 10

What conditions are associated with obesity?

Answer 10

Exercise intolerance

Abnormal reproductive performance

Mesenteric lipoma

Laminitis

Equine Metabolic Syndrome (EMS)

Hyperlipaemia

Developmental Orthopaedic Disease (DOD)

Question 11

How can obesity lead to abnormal reproductive performance ?

Answer 11

Narrows the pelvic canal and makes it more difficult for the foal to get through

Increased risk of dystocia

Question 12

What problems can mesenteric lipomas cause?

Answer 12

On stalks within abdomen and eventually stalks wrap around a piece of intestine and strangulate — COLIC

Question 13

What effect can the endocrine nature of adipose tissue have on a horse?

Answer 13

Increased fat

Increased adipokines

Adipokines antagonise insulin

Horses produce INCREASED insulin to counteract effect of adipokines

Question 14

What is DOD?

Answer 14

Developmental Orthopaedic Disease

If foals and weanlings are overweight, altered insulin levels can affect growing legs

Question 15

What is hyperlipaemia?

Answer 15

When a horse has increased energy requirement it mobilises fat tissues

Fat is mobilised as TRIGLYCERIDES (not ketones)

You get too much fat in blood which is then deposited in the liver and kidneys

Question 16

Describe a typical lamintis stance.

Answer 16

Weight shifted onto heels to relieve painful feet.

Question 17

What horses are of greatest risk of laminitis?

Answer 17

Phenotype of insulin dysregulation and obesity

Question 18

What changes in the feet can be observed in horses with laminitis?

Answer 18

Abnormal growth rings

Pedal bone rotation

Question 19

What epigenetic factors can affect development of a foal?

Answer 19

Genes can be switched on or off during late foetal and early post natal development

DEPENDENT ON MATERNAL DIET

Question 20

What gene may be altered in the foal by epigenetics?

Answer 20

LEPTIN (and adiponectin)

Responsible for

• appetite control
• neuroendocrine function
• fuel metabolism and energy partitioning

GREATER ADIPOSITY and RISK of EMS and OBESITY later in life

Question 21

How can maternal obesity affect foals?

Answer 21

Increase insulin resistance, low grade inflammation and ostochondrosis (part of DOD)

Effect observed until 18 months

Question 22

How should calorie control be approached in horses?

Answer 22

SAME DMI

Grass can provide all dry matter required but high calorie so needs to be controlled

If owner MUST feed concentrates, substitute hay with CHAFF or beet pulp

Question 23

What welfare issues are associated with reducing DMI?

Answer 23

Stereotypes
Colic
Gastric ulcers
Dental problems

Question 24

Why are gastric ulcers associated with a reduced DMI intake?

Answer 24

Saliva is required to buffer acid in the stomach.

This is produced when horses chew

Question 25

Why are dental problems associated with decreased DMI?

Answer 25

The horse is meant to be continually chewing and wearing down its molars

Question 26

How could you restrict grass intake?

Answer 26

Time spent outside
Strip grazing
Grazing muzzle

Question 27

Why can’t you just feed horses grass?

Answer 27

Deficient in some minerals

Need to add BALANCER. (Make sure its low calorie!)

Question 28

What are the benefits associated with increasing exercise in horses?

Answer 28

Promotes glucose uptake and use by skeletal muscle - INDEPENDENT of insulin

Improves insulin sensitivity

Decreases feed intake

Question 29

Other than working a horse, how else could you increase its energy expenditure?

Answer 29

Clip
Don’t rug

Have hay and water at opposite ends of the field - have to walk from one to the other

Circumferential strip grazing - have to walk around outside of field

Question 30

How can you monitor weight loss in a horse?

Answer 30

Weigh tape one time per month

This is better than BCSing because BCS takes much longer to change

Question 31

Why does BCS take longer to change?

Answer 31

Exponential scale

Have to lose a lot of weight to get value down