Water Flashcards
What is the most vital nutrient?
water
basic functions of water
body metabolism
-solvent and transport medium, lubrication and cushioning of organs, chemical reactions
thermoregulation
solvent and transport medium
universal solvent
-blood, saliva, gastrointestinal secretions
transport medium
-delivers nutrients (blood), removes waste products (sweat,urine)
lubrication and cushioning of organs
lubrication: cerebrospinal fluid, pericardial fluid, ocular fluid, mucus, saliva
cushioning: Ocular fluid, amniotic fluid, synovial fluid
chemical reactions
condensation reaction: produces water
hydrolysis reaction: breaks down water
high specific heat capacity
1 cal/g of water to raise temp by 1 degree C
high thermal conductivity
heat transfer from the deep body tissues to the surface
heat distribution
high latent heat of vaporization
580 cal of heat to convert 1 g of water from liquid to vapor
Panting, sweating are efficient ways to lose heat
distribution of body water
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)
factors affecting body water
genotype and age
environmental conditions
feed quality and quantity
physiological state
what is osmosis?
Diffusion of water across a semipermeable membrane
what is tonicity?
Relative solute concentration of two environments separated by a semipermeable membrane
Isotonicity
Hypertonicity
Hypotonicity
fluid balance and electrolytes
Movement of body water (direction and extent) determined by solute concentration:
Plasma proteins
Sodium and chloride (extracellular)
Potassium and phosphate (intracellular)
Factors Affecting Water Requirements
Environmental conditions
Amount, type of diet consumed (e.g., salt, DM content)
Temperature of water
Physiological state (e.g., dry vs. lactating cow)
Water Balance - Input
Water contained in feedstuffs
Metabolic water
Drinking of free water
Water Balance- Output
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
Symptoms of Water Depravation
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)
Water Quality
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
