1. Nutrition

Question 1

Influence of nutrition on farmed animal species productivity

Answer 1

Pig feed represents 70% of the cost of pig meat production
Important to feed diet that gives the best productivity for least possible cost
Least cost can result in less desirable diets being used
Farm animals, least cost diet formulation enormously important issue
Other species cost is not such an issue
Health is important
Anthropomorphism, what would they like?
more expensive dog food, less odorous faeces

Question 2

Water

Answer 2

Essential for life
Variable water content in body mass, newborn 90%, fat animal 50%
Functions: metabolism and temperature regulation
all biochemical reactions in body require water
medium for transport, digesta in GI tract, solutes in blood etc
sweating/panting 1g of water uses up to 580 calories of heat

Question 3

Sources of water

Answer 3

air dry concentrates, 10-15%
dry compound animal feeds 10-14%
succulent feeds, 70%+
root crops 80%+
hay/straw 10-15%
silage 65-84%
drinking water, no energy value, adds palatability
metabolic water (important in hibernating animals)
formed during metabolism by oxidation of hydrogen-containing organic nutrients
yield variable

Question 4

Factors affecting water requirement

Answer 4

Production: tissue growth, egg, milk production
Diet and dry matter intake: food/salt intake
Species and size
Athletic performance
Environment: temperature/rainfall/humidity
Health: hemorrhage, vomiting, diarrhoea

Question 5

Water as a diluent in animal feeding

Answer 5

water contains no energy
therefore same energy from wet and dry feedstuffs, much more weight of the wet food would need to be fed
often convert fed amounts of feed and feed analysis to a dry matter basis (100% DM)

Question 6

Carbohydrates

Answer 6

70% DM of plants
less than 1% of animal body
contain CHO
classified on basis of no. of carbon atoms and no. of molecules of sugar in compound
sugars are carbohydrates with less than 10 monosaccharides
polysaccharides e.g. starch, cellulose

Question 7

Starch

Answer 7

storage polysaccharide for cereals and root crops
made of amylose and amylopectin
amylose: linear structure repeating glucose units linked at C atom 1 and 4 or 1 and 6 through a linkages
amylopectin: repeating glucose units bush like structure different linkages to amylopectin
different starches diff amounts of amylose and amylepectin and different physical properties
mammalian enzymes: pancreatic and salivary amylase
almost completely digestible if exposed to enzymes

Question 8

Cellulose

Answer 8

repeating glucose units but have linkages at C atoms 1 and 4 b linkages
cellulose chains formed in an ordered manner to produce micro-fibrils, held together by inter- and intra- molecular hydrogen bonding
cannot be digested by mammalian enzymes
cellulose is the major component of plant cell walls
microflora in rumen produce cellulase to hydrolyse cellulose
some species can utilise large quantities of cellulose
often present in association with lignin

Question 9

Hemicellulose

Answer 9

alkali soluble cell wall polysaccharides
closely associated with cellulose
name misleading
contains D-glucose, D-galactose, D-mannose, D-xylose, L-arabinose, Uronic acids
joined together in various combinations
complex group of cell wall polysaccharides that cannot be digested by mammalian enzymes

Question 10

Lignin

Answer 10

Not strictly a carbohydrate
intercellular cement associated with plant cellulose and hemicellulose
confers chemical and biological resistance to cell wall carbohydrate
very resistant to enzyme digestion
as plant maturity increases, lignification increases
reduces digestibility of feed