(T2) Lecture 9a - Lifecycle nutrition of horses

Question 1

What is the estrous cycle influenced by?

Answer 1

• photoperiod
• nutrition
• physiological condition
• environmental temperature

Question 2

What is reason for seasonal polyestrous?

Answer 2

• most forage available in spring and summer
• seasonal effect of food being available in excess and short supply; also tied to photoperiod
• want foal to be born when more food is available

Question 3

How to nutritionally manage good estrous?

Answer 3

body condition score

Question 4

Body Condition Scoring

Answer 4

Poor: 1-3

Moderate: 4-6

Fat: 7-9

Question 5

What is an example of how to score a horse’s body condition?

Answer 5

Based on 6 body sites

Cresty Neck Score: you can use the neck for scoring body condition in a horse

Question 6

What is very important during gestation?

Answer 6

Body Condition Score

Question 7

Optimum BCS during estrous cycle =

Answer 7

• increase fertility
• increase milk yield
• increase health
• shorter follicular phase in estrous = increase cycles
• shorter winter anestrous

Question 8

How does a low BCS affect the estrous cycle?

Answer 8

longer anestrous
- decreased hormone levels

Question 9

Homeorhesis vs Homeostasis

Answer 9

Homeorhesis: controlled change

Homeostasis: controlled lack of change

Question 10

What is the ideal gain during gestation?

Answer 10

Gain 12-15% above normal BW

Question 11

5 energy requirements to consider during pregnancy

Answer 11

1. maintenance of dam
2. deposition of fetal and placental tissue
3. hypertrophy of the uterus
4. mammary development
5. maintenance of 2, 3, 4

Question 12

Why do pregnant mares have added maintenance requirements?

Answer 12

Because the additional tissues grown are very metabolically active

Question 13

What are the DE requirements for pregnancy if the mare is at a normal BCS?

Answer 13

Met by DEm for first 5 months, then increases gradually each month
- later into gestation, there is a gradual increase in energy requirement needed to support the mare and fetus

Question 14

If additional energy is not supplied to pregnant mares with ideal BCS, what can happen?

Answer 14

1. delayed estrous
2. reduced conception
3. embryonic death

Question 15

What happens to protein requirements between pregnancy at 5 months to parturition?

Answer 15

Addition for fetal gain and non-fetal tissue needs

Question 16

How are mineral and vitamin requirements affected by pregnancy?

Answer 16

Increased requirements during late gestation
- for vitamin A and E its a “safety factor”

Question 17

What happens with feed during parturition?

Answer 17

1. reduce feed intake 24 hrs before birth
   - good quality hay, low-energy cereal
2. after parturition, energy and protein needs must be met
   - first bran mash, secondly cereal and protein
3. restrict concentrate (aka starch and sugars) feeding to 10 days postpartum
   - avoid excess milk secretion and Gi disturbances in foal

Question 18

What is milk yield influenced by?

Answer 18

1. feed consumption during late gestation
2. feed quality
3. water availability
4. nutrient and energy intake
5. interaction btw mare and foal(s)

Question 19

What would be a consequence of decreased milk production?

Answer 19

malnutrition of the foal

Question 20

Protein requirements for lactation

Answer 20

• sensitive to quality
• elevated CP requirement + milk production

Question 21

Calcium requirements for lactaion

Answer 21

• Increased demand
• if you see an increase in PTH = not getting enough Ca

Question 22

What are some factors that would increase energy requirements of stallions?

Answer 22

Increased activity

Question 23

5 physical signs of aging in horses

Answer 23

1. chronically low BCS
2. loss of muscle mass
3. “sway” backed appearance
4. gray coat
5. dental disease

Question 24

2 general considerations of aged horses

Answer 24

1. Large metabolic changes
2. Dental abnormalities are common
   - alter physical form of ration to increase digestibility
   - feed haylage or chopped hay
   - soak hay or hay cubes in water
   - supplement oil to increase energy density

Question 25

Why is MER typically lower in older animals?

Answer 25

less activity

Question 26

Why is it suggested that protein requirements decline with aging?

Answer 26

Tie this to activity level and also if they lose muscle mass they have less protein turnover

Question 27

What is Cushing’s Disease? What are 3 clinical signs? What are the symptoms?

Answer 27

Pituitary pars intermedia dysfunction

Clinical signs
- increase ACTH
- increase POMC
- increase CORTISOL!!!

Symptoms
- hypertrichosis (excess hair growth)
- sweating
- muscle wasting
- risk of laminitis
- insulin resistance

Question 28

Treatment for Cushing’s Disease

Answer 28

Dopaminergic control

*with nutrition (less starch and sugar) we can help control the symptoms

Question 29

Equine Metabolic Disease

Answer 29

• obese
• hyperinsulinemia
• laminitis
• etiology (unknown, genetic)

Question 30

What would a possible treatment be for equine metabolic disease?

Answer 30

too much insulin = reduce amount of insulin by feeding less starch and sugar (cereal grains) and more forage

Question 31

What is Laminitis? What are the causes?

Answer 31

Inflammation of laminae causing distal phalanx to detach from inner hoof

Causes
- sepsis/endotoxemia
- toxins
- obesity
- trauma
- fructans

Question 32

Nutritional management of laminitis

Answer 32

*laminitis in most cases is preventable!!!
- >50% diet related
- too much pasture or grain (rapidly digestible CHO contributing to onset)

Question 33

When do mares have increased nutrient needs?

Answer 33

During last 6 months of gestation
- increased requirements continue into lactation