Water

Question 1

What is the most vital nutrient?

Answer 1

water

Question 2

basic functions of water

Answer 2

body metabolism
-solvent and transport medium, lubrication and cushioning of organs, chemical reactions
thermoregulation

Question 3

solvent and transport medium

Answer 3

universal solvent
-blood, saliva, gastrointestinal secretions
transport medium
-delivers nutrients (blood), removes waste products (sweat,urine)

Question 4

lubrication and cushioning of organs

Answer 4

lubrication: cerebrospinal fluid, pericardial fluid, ocular fluid, mucus, saliva
cushioning: Ocular fluid, amniotic fluid, synovial fluid

Question 5

chemical reactions

Answer 5

condensation reaction: produces water

hydrolysis reaction: breaks down water

Question 6

high specific heat capacity

Answer 6

1 cal/g of water to raise temp by 1 degree C

Question 7

high thermal conductivity

Answer 7

heat transfer from the deep body tissues to the surface

heat distribution

Question 8

high latent heat of vaporization

Answer 8

580 cal of heat to convert 1 g of water from liquid to vapor

Panting, sweating are efficient ways to lose heat

Question 9

distribution of body water

Answer 9

Total body water content is inversely related to body fat content
Water content of fat-free body is 70-75% (mean = 73%)
% body fat = 100 – (% body water/0.732)

Question 10

factors affecting body water

Answer 10

genotype and age
environmental conditions
feed quality and quantity
physiological state

Question 11

what is osmosis?

Answer 11

Diffusion of water across a semipermeable membrane

Question 12

what is tonicity?

Answer 12

Relative solute concentration of two environments separated by a semipermeable membrane
Isotonicity
Hypertonicity
Hypotonicity

Question 13

fluid balance and electrolytes

Answer 13

Movement of body water (direction and extent) determined by solute concentration:
Plasma proteins
Sodium and chloride (extracellular)
Potassium and phosphate (intracellular)

Question 14

Factors Affecting Water Requirements

Answer 14

Environmental conditions
Amount, type of diet consumed (e.g., salt, DM content)
Temperature of water
Physiological state (e.g., dry vs. lactating cow)

Question 15

Water Balance - Input

Answer 15

Water contained in feedstuffs
Metabolic water
Drinking of free water

Question 16

Water Balance- Output

Answer 16

Urine
Obligatory amount required to excrete waste products via the kidney
About 500 mL/d in adult humans

Feces
Significant differences among species

Evaporation
Lungs during respiration
Panting
Skin
Sweat high in K in cattle, but Na in humans

Question 17

Symptoms of Water Depravation

Answer 17

Reduced production performance (e.g., DMI, MY)
Increased heart rate, body temperature, respiration
Lack of muscle coordination
Sunken eyes, shriveled skin
Death (loss of 12% body water)

Question 18

Water Quality

Answer 18

Organoleptic properties
Odor, taste, color, feel
Physico-chemical properties
pH, hardness, total dissolved solids

toxic compounds- heavy metals, pesticide residues
minerals- nitrates, sulfates
bacteria, coliforms, coccidia

Clear, colorless, odorless
No undesirable flavor
Low total solids
Low levels disease organisms or pesticides