4b Nutrient Requirements of Horses 1 Flashcards

1
Q

What is the definition of a mature horse?

A
  • considered mature at 86% of body weight (36 months)

- dependent on breed/use (2-6)

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2
Q

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

A
  • Breed
  • Age
  • Reproduction
  • Activity level
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3
Q

Define maintenance energy requirement (MER)

A
  • 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)
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4
Q

How is MER established in mature horses?

A
  • metabolic body weight (surface area vs body weight)
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5
Q

Explain the need for metabolic body weight.

A
  • not all tissues require energy to be maintained

- MBW ensures that these tissues are not accounted for

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6
Q

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

A
  • heat of product formation
  • heat of digestion and absorption
  • heat of waste formation and excretion
  • heat of fermentation
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7
Q

Why does gut size matter in heat production?

A
  • in animals that ferment a lot of feed, cells proliferate much more and gut is bigger and heavier
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8
Q

How can body condition score affect requirements?

A
  • low muscle tissue = low energy requirement
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9
Q

What is the average DEm of horses?

A

30.3kcal/kg BW/day

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10
Q

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

A
  • low because animals were confined
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11
Q

What were the calculated average and elevated energy requirements?

A
  • average 10% increase

- elevated 20% increase

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12
Q

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

A
  • ambient temperature
  • wind velocity
  • global solar radiation
  • precipitation
  • relative humidity
    (horses must maintain constant core body temperature)
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13
Q

What effects can extreme cold cause?

A
  • increased eating
  • increased hair coat
  • decreased rectal temperature
  • decreased respiratory rate
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14
Q

What effects can extreme heat cause?

A
  • increased sweating rate
  • increased respiratory rate
  • decreased feel intake
  • increased water intake
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15
Q

What is a thermoneutral zone?

A
  • when metabolic heat production does not need to increase to maintain thermostability
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16
Q

What is the general lower and upper critical temperature?

A
  • 15C

+ 35C

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17
Q

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

A

2.5%

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18
Q

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

A

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

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19
Q

What is the total body water in adult horses?

A
  • 62-68%

- water balance achieved if water loss = water intake

20
Q

How long can water restriction be tolerated?

A
  • extended periods but more so tolerated with lack of feed as well
21
Q

What are the 4 main types of water loss?

A
  • 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
Q

Why is there more water loss with hay diets

A
  • hay higher in soluble fibre so more water in poop
23
Q

What are the 3 main types of water intake?

A
  • drinking (5-9.6L/100kg)
  • food (hay less moisture than pasture)
  • metabolic water (0.68L/100kg)
24
Q

What is the main determinant of total water intake?

A
  • 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