Water as a Nutrient

why is water considered the most essential nutrient

it makes up around 60% of the adult body, 85-87% of milk, has the greatest daily requirement, and must be supplied continuously

when is water intake greatest in livestock

during and after feeding

what water quality problem led to cattle deaths in Saskatchewan in 2017

high total dissolved solids and high sulfates caused neurological issues and death, 7000 mg/L is recommended

can water be toxic?

yes, excessive water intake can be fatal

what is aquagenic urticaria

a rare condition where exposure to water causes hives, rashes, lesions and respiratory distress

what are two basic functions of water in animals

1. component in metabolism (solvent, transport, reactions, lubrication)

2. Thermoregulation (heat dissipation and buffering)

how does water act in metabolism

universal solvent, transport medium for nutrients/waste, medium for hydrolysis/oxidation, cushioning organs, forming fluids

what is metabolic water

• water formed during oxidation of nutrients

• fat produces more water because you add more oxygen during oxidation

what role does water play in thermoregulation

• high specific heat capacity (buffers heat)

• high thermal conductivity (transfer heat to surface)

• high latent heat of vaporization (efficient cooling via panting/sweating)

what are the main sources of water for livestock

• drinking/free water

• water in feedstuffs

• metabolic water

which feed contain the highest water content

• beets (87%)

• potatoes (75%)

• silage (55-65%)

how does age affect water and fat content in swine

as age increases, water % decreases while fat % increases

what are symptoms of water deprivation

Reduced feed intake, ↑ heart rate, ↑ body temp, ↑ respiration, muscle incoordination, sunken eyes, shriveled skin, and death (12% body water loss)

what factors affect livestock water requirements

Environment (temperature), feed type/amount, diet salt/protein, water temperature, physiological state (dry vs. lactating), and health status

what are some methods of measuring water intake

in-line water meters, tracking water flow to troughs, measuring for 5-10 days, and including water from ration (silage)

what are the features of good quality water

clear, colorless, low solids, free of disease organisms/pesticides, no undesirable odor or taste

name common contaminants measured in water quality tests

nitrates/nitrites, sulfates, heavy metals (lead, mercury, copper, zinc), pesticides, bacteria, blue-green algae

how is water quality improved

sand filters (remove algae/OM), reverse osmosis (remove nitrates, sulfates, Fe, reduce hardness/solids)

When cattle are switched from a barley silage-based diet to an alfalfa hay diet, what change occurs in their water intake and why?

Water intake increases because hay is much drier, requiring more water intake to meet hydration needs

A pig’s diet changes from 10% crude protein to 16% crude protein. How does this affect water intake and why?

Water intake increases because more dietary protein leads to higher urea production, requiring more water for excretion in urine

why is water considered a universal solvent

because a wide variety of compounds are soluble in water 

what happens to water intake at higher ambient temperatures, and why?

water intake increases due to thermoregulation needs. Animals lose more water through sweating and panting (evaporative heat loss) and must drink more to maintain constant body water content

T or F: Metabolic water from oxidation of glucose and fatty acids is the largest source of water for farm animals

False

Intake of which dietary constituent is positively correlated with water intake

Salt. higher salt intake increases water intake to maintain osmotic balance

which physical property of water allows heat dissipation through panting and sweating, helping animals regulate temperature

high latent heat of vaporization

metabolic reactions in aqueous environments produce heat, but which physical property of water minimizes changes in intracellular temperature

high specific heat capacity

where would you collect water samples of laboratory analysis in livestock systems

from the water trough (where animals are drinking)

T or F: animals are efficient at storing water

False

how does water intake differ between lactating dairy cows and dry cows, and why?

lactating cows have much higher water intake because milk is mainly water and lactating cows consume more dry matter.