lecture 14 - Water

is water a nutrient

yes

what is the most consumed nutrient

water

what are the main functions of water

solvent

transport medium and diluent

biochem intermediate

describe how water is solvent

many substances are soluble and ionize in water

describe how water is a transport medium and diluent

carries substances in GIT, blood, fluids, cells, and secretions

describe how water is a biochem intermediate

consumed during hydrolysis

formed during condensation

what are some major sources of water

drinking water

food

metabolic water

describe metabolic water

formed during catabolism of nutrients from diet or tissue

how much water is formed from glucose catabolism

6 H2O

why is metabolic water important

about 10% of total input for most animals

chief form of water for some animals

metabolic water is the chief form of what for what animals

desert animals

hibernating animals

whales

whats the gross amount of metabolic water per g protein

0.4 g

whats the gross amount of metabolic water per g carbs

0.56 g

whats the gross amount of metabolic water per g fat

1.07 g

describe the net amounts of water

less than gross amount

may be highest for carbs

why is net amount of metabolic water less than gross amount of metabolic water

protein leads to loss of water in urine

some water is lost during catabolism via the process of dissipating heat, especially high for fat

what are some ways of water loss

urine

feces

milk

vaporized/insensible water

describe vaporized/insensible water

from respiratory tract/skin

partly, but not completely, from sweat

how much drinking water is generally needed per kg DMI

2-5 kg drinking water

the amount of drinking water increases with

↑ env. temp

↑ dietary protein

↑ dietary salt

↑ milk output

if req amount of drinking water isnt not met what happens

↓ water loss

↓ feed intake

↓ productivity

define total dissolved solids (TDS)

total inorganic and organic substances in water in dissolved or colloidal form

what is the idea amount of TDS

<2.5 g/L

TDS range of 1-5 g/L...

can cause diarrhea in unadapted animals

TDS range of 3-5 g/L...

can cause watery feces and mortality in poultry

TDS range of 5-7 g/L...

should not be used for poultry, swine, lactating, or growing animals

TDS of 10 g/L is generally...

unfit under any conditions

should inorganic compounds and elements have defined safe limits that should not be exceeded

yes

what are some examples of microbial pathogens

E. Coli, salmonella, and other fecal coliforms

where are microbial pathogens found

in water contaminated by feces, cud, and other sources

what is the recommended limit of microbial pathogens

1000 coliforms/L

what are cyanobacteria

photosynthetic bacteria that are non infectious, but produce toxins like neurotoxins

cannot be consumed and must be avoided

where are cyanobact found

in ponds and other surface water

caused by high N and P from manure or fertilizer

the total body is what percent water

1/2 to 2/3 water

variation in amount of water in body is mostly due to

fat

fat free body is about 73.2% water

how can body fat be measaured

100- (%H2O/0.732)

what is the typical half life for water for cattle

3.5 days

how is water measured

via deuterated or tritiated water

what is water used to measure in cows

measure milk intake for suckling ruminants