4b Nutrient Requirements of Horses 1 Flashcards Preview

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Flashcards in 4b Nutrient Requirements of Horses 1 Deck (45):
1

What is the definition of a mature horse?

- considered mature at 86% of body weight (36 months)
- dependent on breed/use (2-6)

2

What are 4 factors that influence the energy requirements of horses?

- Breed
- Age
- Reproduction
- Activity level

3

Define maintenance energy requirement (MER)

- amount of dietary energy needed to prevent change in total energy contained in the body of a horse
- does not include energy needed to support additional activity (gestation, lactation, growth, performance)

4

How is MER established in mature horses?

- metabolic body weight (surface area vs body weight)

5

Explain the need for metabolic body weight.

- not all tissues require energy to be maintained
- MBW ensures that these tissues are not accounted for

6

Which 3 parts of daily heat production form together the heat increment?

- heat of product formation
- heat of digestion and absorption
- heat of waste formation and excretion
- heat of fermentation

7

Why does gut size matter in heat production?

- in animals that ferment a lot of feed, cells proliferate much more and gut is bigger and heavier

8

How can body condition score affect requirements?

- low muscle tissue = low energy requirement

9

What is the average DEm of horses?

30.3kcal/kg BW/day

10

Do you think the minimum maintenance requirement calculated is high, low or correct?

- low because animals were confined

11

What were the calculated average and elevated energy requirements?

- average 10% increase
- elevated 20% increase

12

What are the 5 climatic variables that have effects on energy?

- ambient temperature
- wind velocity
- global solar radiation
- precipitation
- relative humidity
(horses must maintain constant core body temperature)

13

What effects can extreme cold cause?

- increased eating
- increased hair coat
- decreased rectal temperature
- decreased respiratory rate

14

What effects can extreme heat cause?

- increased sweating rate
- increased respiratory rate
- decreased feel intake
- increased water intake

15

What is a thermoneutral zone?

- when metabolic heat production does not need to increase to maintain thermostability

16

What is the general lower and upper critical temperature?

- 15C
+ 35C

17

How much should DE intake increase for each degree below LCT?

2.5%

18

How can feed management help animals cope with hot or cold temperatures?

feeding a more forage based diet in winter increases fermentation which helps them maintain heat

19

What is the total body water in adult horses?

-62-68%
- water balance achieved if water loss = water intake

20

How long can water restriction be tolerated?

- extended periods but more so tolerated with lack of feed as well

21

What are the 4 main types of water loss?

- fecal losses (3-3.8L/100kg)
- urinary losses (0.5L/100kg)
- respiratory losses (0.8-2.1L)
- cutaneous losses (1.7-3.3L/100kg)

22

Why is there more water loss with hay diets

- hay higher in soluble fibre so more water in poop

23

What are the 3 main types of water intake?

- drinking (5-9.6L/100kg)
- food (hay less moisture than pasture)
- metabolic water (0.68L/100kg)

24

What is the main determinant of total water intake?

- body weight

25

What is the only amino acid requirement that has been established in horses?

lysine

26

Why can you feed ruminants non protein nitrogen but not horses?

- horse cannot absorb amino acids after small intestine

27

Protein digestibility is correlated to ______

dietary CP content

28

How do you calculate the lysine requirement?

lysine (g/d) = CP requirement x 4/3%

29

What is an ideal protein?

- 100% biological value
- ability for a specific dietary protein to supply amino acids in the relative amounts required for protein synthesis by body tissues

30

How can the ideal protein be estimated in horses?

- by using muscle tissue
- use these ratios to estimate requirements for EAA

31

What are the effects of protein deficiency?

- weight loss in adult horses
- fetal loss in pregnant mares
- decrease milk production in lactating mares
- loss of muscle in exercising horses

32

What are the effects of protein excess?

- increases urea which is excreted in urine
- increases water loss
- increases water requirements
- decrease growth in younger horses
- increases Ca and P loss in weanling horses

33

What are some examples of carb containing feeds?

- forage
- concentrates
- grain by products

34

Do all carbs contain the same amount of gross energy?

- yes, but different digestible, metabolizable and net energies

35

What fractions are currently used?

- NDF neutral detergent fibre (cellulose, hemi cellulose nd lignin)
- NFC non-fibre carbohydrates (mono, di, oligosaccharides and starch)

36

What is the new proposed system of fractions?

- hydrolyzable CHO
- rapidly fermented
- slowly fermented

37

Cecal VFA production can meet up to what percentage of MER?

- 30%

38

What are fats used for in the diet?

- improve energetic efficiency
- enhance body condition
- diminish excitability
- help increase fat oxidation
- facilitate absorption of ADEK vitamins

39

What are the 2 essential fatty acids and what are their requirements?

- linoleic acid
- alpha-linolenic acid
- no requirements

40

Do added fats have increased or decreased fat digestibility?

- increased

41

What is calcium important for and what is the requirement?

0.04g Ca/kg BW per day
- muscle contraction, cell membranes, enzymes, blood homeostasis

42

What is phosphorous important for and what is the requirement?

0.28g/kg BW per day
- important for energy reactions and synthesis of nucleic acids

43

What is the Ca:P ratio?

~1.4:1

44

What are potassium and sodium requirements, and how are they met?

25g K/day 10g Na/day
- salt block and forages

45

What are the 3 main vitamin requirements?

A D E