Equine Chronic Weight Loss

Question 1

list four examples of how herd dynamics and other environmental conditionals might interfere with a horse having adequate access to food and water.

Answer 1

1. competition for food/bullying from pasture mates
2. inadequate calories - not enough food/poor quality food
3. inability to consume food - poor dental health, neuro or physiological dysfunction
4. malabsorption

Question 2

how much does a horse eat per day in dry feed?

Answer 2

about 2% of its body weight

Question 3

what 2 conditions lead to an inability to absorb or utilize nutrients from feed in adult horses?

Answer 3

1. Malabsorption disorders: infiltrative inflammatory bowl diseases
2. major organ dysfunction

Question 4

while eating hay, horse drops partially chewed bundles on the ground. What is the term used to describe this horses eating problem?

Answer 4

quidding

Question 5

malabsorptive diseases of adult horses and weanlings

Answer 5

adults:
- bowel is infiltrated by a population of inflammatory or neoplastic cells
- infiltrative cells interfere with absorption of nutrients

weanlings:
- similar syndrome due to lawsonia intracellularis infection

Question 6

how do you diagnose malabsorption?

Answer 6

Glucose Absorption Test

Question 7

describe a glucose absorption test

Answer 7

1. withdraw feed for 12 hours
2. administrate oral glucose in water
3. measure blood glucose prior to administration then every 30 minutes for up to 3 hours

Normal: blood glucose doubles by 90-120 minutes and returns to resting values by 360 minutes (6 hrs)

Abnormal: blood glucose fails to double by 90-120 minutes

Question 8

T/F: chronic disease of any organ resulting in weight loss is common

Answer 8

F, this is not common so search for a treatable cause first

Question 9

what is a weight based on a weight tape good for?

Answer 9

great for assessing trends but not actual weight

Question 10

what are some underlying problems you should eliminate for a horse with weight loss?

Answer 10

• competition for food, feed type and/or access to water
• restore dental health
• deworm if needed

Question 11

when introducing feed changes it should be slow taking a minimum of __ to __ days to make any changes

Answer 11

7 to 10 days

Question 12

if you’re trying to increase a horses feed you should increase it by no more than how much every week?

Answer 12

2 lbs

Question 13

how should pasture be introduced to horses?

Answer 13

place on pasture in early spring before significant grass growth and then wait until after mid- june when fructans drop

• grazing muzzle may also be beneficial

Question 14

if a horse does not gain weight, what additional diagnostics should be performed?

Answer 14

• CBC, blood chemistry, urinalysis
• abdominal palpation per rectum
• abdominocentesis
• abdominal ultrasound

Question 15

what are the specific infiltrative diseases of weanling foals?

Answer 15

Lawsonia intracellularis
rhodococcus equi

Question 16

proliferative enteropathy (lawsonia intracellularis) pathogenesis

Answer 16

disorder of weanling foals (4-5mths old)

pathogenesis: invades crypt cells of ileum and caused mitotic division and hyperplasia -> gut becomes thickened -> malabsorption -> foals experience weight loss and hypoproteinemia

Question 17

Lawsonia Dx

Answer 17

Hx of adequate access to food but poor weight gain
- small for age
- poor coat
- quiet
- peripheral edema
- skin lesions

Lab:
hypoproteinemia and hypoalbuminemia

Ultrasound: thickened small intestine

Fecal PCR detection

Question 18

Lawsonia Tx

Answer 18

Macrolids (keep out of direct sun)
Tetracyclines