Obesity in the Horse

Question 1

Define obesity. What about in Humans?

Answer 1

A medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health, leading to reduced life expectancy and/or increased health problems.

In humans, it is defined by BMI wherer 25-29.9 is overweight, 30-39.9 is obese and >40 is severely obese. It is also defined using waist circumference (>94cm in men, >80cm in women)

Question 2

2 ways to recognised fatness in horses = ?

Answer 2

BCS or CNS (crest neck scoring). BMI not useful as most owners don’t have accurate scales. BCS is measured on a 1-5 or 1-9 scale. CNS emphasises regional rather than general adiposity.

Question 3

Describe the epidemiology of equine obesity.

Answer 3

In a study of scottish riding establishments, 45% animals were fat or very fat and in a study in the south east 16% horses and 83% ponies were overweight (4/5)

Question 4

4 circumstances where obesity is more common

Answer 4

• breed (draught, cob, native and welsh)
• ‘good doers’
• pleasure and not athletic uses
• summer> winter

Question 5

What stimulates the summer gain in adiposity?

Answer 5

Increased POMC secretion by pituaitary pars intermedia which stimulates appetite and adipogenesis.

Question 6

Why does obesity develop? 2

Answer 6

husbandray practices promoting excess calorie intake and physical inactivity

Question 7

Result or excess adiposity and chronic persistence

Answer 7

Adverse effects including generating an insulin resistance and a mild pro-inflammatory state.

Question 8

Name 3 equine conditions associated with obesity and NOT IR

Answer 8

• exercise intolerance
• abnormal reproductive performance
• mesenteric lipoma (may strangulate)

Question 9

Name equine conditions associated with obesity AND IR (5)

Answer 9

• laminitis
• EMS
• hyperlipaemia
• DOD (developmental orthopaedic disease)
• PPID (=Equine Cushing’s)

Question 10

How may obesity lead to laminitis? 3

Answer 10

Changes due to obesity in insulin signalling, inflammatory cytokines and endothelial dysfunction

Question 11

What is pre-programming of genes dependent on?

Answer 11

Maternal diet

Question 12

What happens in mares who are obese?

Answer 12

maintain increased concentrations of glucose and NEFA which induces epigenetic changes and possible permanent changes in appetite control, neuroendocrine function, fuel metabolism and energy partitioning during early development. Leads to greater adiposity and risk of obesity in later life.

Question 13

What happens with sub-optimum nutrition in utero? Why? 2

Answer 13

Increases risk of obesity in early childhood due to decreased total pancreatic weight and decreased number of B cells. These structural changes may contribute to impaired glucose homeostasis.

Question 14

What should be maintained in a horse’s diet when controlling calorie intake?

Answer 14

DMI

Question 15

What are the welfare concerns associated with restricting DMI? 4

Answer 15

• stereotypies
• colic
• gastric ulcers
• dental problems

Question 16

What predisposes gastric ulcers?

Answer 16

low fibre diets

Question 17

What predisposes simple obstructive and distension colic?

Answer 17

horses that chew wood

Question 18

Can grass provide a horse with all the DMI?

Answer 18

Yes but can contain excess calories

Question 19

How can an owner restrict a horse’s intake? 2

Answer 19

Time or geography

Question 20

Will a grass only diet be mineral deficient?

Answer 20

Yes –> add balancer

Question 21

How much hay should be fed if stabled?

Answer 21

1.5% body weight

Question 22

How can you slow the consumption of hay?

Answer 22

small holed hay nets, hay bags, hanging hay net from ceiling centre. Can substitute hay with chaff or unmolassed beet pulp (1lb of beet pulp for 1.5lb hay)

Question 23

Why is exercise the best way to promote weight loss?

Answer 23

promotes glucose uptake and use by skeletal mm by insulin-independent route that persists for 24 hours; improving insulin sensitivity, reducing inflammation and decreasing feed intake.

Question 24

List some other ways of increasing energy expenditure

Answer 24

clipping, not using rugs, having hay and water at opposite ends of field, circumferential strip grazing.