Animal Nutrition Flashcards
nutrient
the fundamental chemical constituents of food
nutrition
the sum of the processes concerned with the utilization of feed nutrients by animals
importance of animal nutrition
economics: feed often represents >50% of production costs on a livestock operation
prices have been very volatile in recent years
nutrition can impact product quality (marbling- intramuscular fat in beed, omega 3 fatty acids in eggs)
environment: greater production per animal has reduced the environmental footprint of animal agriculture
processes
first importance= maintenance (support of body proccesses)–> growth (increase in weight or size) –> reproduction (proliferation of species) –> animal products (used for human consumption) =last importance, high nutrient levels
feed nutrient
any substance found in food used for body function
6 classes of nutrients
5 classes of animal feed
classses of nutrients
water, carbohydrates, proteins, fats, minerals, and vitamins
water
most important nutrient for animals
need 3-4 times as much as solids
functions: nutrient transport, body temperature regulation, maintaining body fluids, lubrication
deficiencies can affect feed intake
water quality can affect intake: salt, sulfates, nitrates
acquired by: drinking, part of solid food, body metabolism
losses by: urine, feces, sweat and lungs
carbohydrates
primary role is to supply energy
major component of diet (%)
grasses, hay, grains
soluble(simple, alpha linkages–easier for body to break down) v. insoluble (complex, beta linkage)
soluble carbohydrates
simple, alpha linkages
monosaccharides= glucose
disaccharides= lactose
polysaccharides= starch
insoluble carbohydrates
complex, beta linkages
cellulose
hemicellulose
lignin -very hard to digest, structural components of plants-stems
proteins
building blocks of body
composed of amino acids
-essential: not formed in body in adequate amount, must be supplied in diet
-nonessential: formed in body, do not have to be in diet
shortage of any amino acid is limiting
proteins are 16% nitrogen, 1 in every 6.25 parts is N
analyze for N and multiply by 6.25 to arrive at protein value
ruminants can use non-protein nitrogen (NPN) if no more than 50% in diet (urea-elk, cows, etc)
fat
primary role is to supply energy
fat is 2.25 times as high in energy as CHO and protein
animals are limited in ability to use fat
other functions:
insulation
animal product quality (marbling)
energy partitioning
gross energy (GE)
\/—————————->fecal energy (FE)
\/
digestible energy (DE)
\/—————————-> urinary energy (UE). gaseous energy (GE)
\/
metabolizable energy (ME)
\/—————————->heat increment (HI)
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net energy (NE) –maintenance and production
measuring energy
gross energy (GE)
-heat of combustion
-intake energy
digestible energy or total digestible energy (TDN)
TDN= gross energy-fecal energy
metabolizable energy (ME)
ME= TDN- (urine and gas) or ME= gross energy- (feces, urine, gas)
net energy (NE)
NE= gross energy - all losses (maintenance, consumption, movement, and digestion
Nem (Net energy for maintenance) = metabolism, activity, heat, cool
Nep (Net energy for production) = growth, milk production, fattening, eggs, wool, work
Nei (net energy for lactation)
Neg (net energy for growth)
minerals
structure and balance
macrominerals
-need in large amounts (Ca, P, Na, Cl, S, Mg)
microminerals
-need in small amounts, trace minerals
-I, Zn, Mn, Co, Cu, Fe, Mo, Se, F
excess minerals are toxic
vitamins
catalysts and regulators
fat soluble
- A, D, E, K
-K is synthesized in rumen
-D is synthesized by sunlight on skin
water soluble
-B complex and C synthesized in rumen
five classes of feed
concentrate -grains
roughage/forage -grasses and hays
protein supplement
non-nutritive additives
vitamins/minerals
concentrates
high digestibility (80-90%)
high available energy
low fiber <18%
examples
corn, sorghum, barely, molasses, bakery by-products
roughages
less digestible (50-65%)
high fiber, cellulose
low available energy –> but can be utilized by ruminants
examples
hay, silage, grass, straw
why feed roughages? rumen function
protein supplements
feeds containing greater than 20% crude protein
contribute amino acids (nitrogen)
examples
soybean meal, meat and bone meal, urea, and fish meal
non-nutritive additives
works to increase gain efficiency
examples
antibiotics (minimize disease), ionophores (change rumen function–makes more efficient, makes safer to feed heavier grain diets), flavor compounds, hormone-like compounds (keep feedlot heifers out of heat (MGA))
vitamins/minerals
needed in very small amounts
-water soluble and fat soluble
-macro and micro (trace) minerals
proximate analysis
an approximation of the different nutrients in a sample
-dry sample down (moisture versus dry matter)
-dry matter (organic matter v ash (inorganic matter-mineral))
-organic matter (protein v non-nitrogenous matter)
-non nitrogenous matter (fat v carbs)
-carbs (crude fiber v nitrogen free extract)
Van Soest fiber system
system for describing chemical makeup of the fibrous components of feedstuffs
-defines properties of the plant cell walls
a. Neutral Detergent Fiber (NDF): isolates the cellulose, hemicellulose, and lignin (basically indigestible)
-negatively correlated to feed intake
b. Acid Detergent Fiber (ADF): isolates the cellulose and lignin components of the roughage
-negatively correlated to digestibility of the feed
