Nutrition and Feed Flashcards
biological value of a protein
high biological value - contains the essential AA required by in a proportion similar to that required by the consumer
low biological value - one or more essential AA are scarce
limiting AA - AA in shortest supply in relation to need
ration formation
goal: to provide the animal w/ a balanced diet containing the nutrients required to meet its physiological needs
needs include:
-maintenance requirements + additional needs for: growth pregnancy lactation work etc.
must consider: nutrient composition of feedstuffs
-digestibility
-palatability
diet
all feedstuffs being consumed including water
ration
specific feeds being given in a 24hr period
specific quantities
national research council
NRC
Publishes:
-nutrient requirement of domestic animals
-nutrient contents of ration ingredients
physiological control of feed intake
energy and gut fill
in energy density is too low then cant consume enough due to gut capacity
feedstuff components
water (moisture) protein fat carbohydrates vitamins minerals energy (calories)
proximate analysis
a general approximation of the feeds (or rations) content of major nutrient groups
a chemical analysis
moisture content determination
dry the feed sample
weight before - weight after = moisture content
kjeldahl
chemical analysis of total nitrogen in the sample
ether extraction
removes fat from the sample
weight before - weight after = fat content
measure soluble carbohydrate and protein
boil in acid
boil in alkali
then left w/ crude fiber and ash
ash
minerals
measure soluble carbohydrates
nitrogen free extract (NFE)
100% - CP - fat - crude fiber - ash = NFE
calories in feed
bomb calorimeter
carbs = 4kcal/g
protein = 4kcal/g
fat = 9kcal/g
gross energy
includes all energy in feed
not all available to the animal
bomb calorimeter test
digestible energy
how much energy does NOT end up in the feces
= energy absorbed
metabolized energy
what is left after accounting for energy lost in feces, urine, and gases
net energy
left after losses in feces, urine, gases, and heat increment
available for maintenance, growth, lactation, work, etc.
heat increment
energy lost in fermentation and in metabolic processes associated with work of digestion
digestibility trials
estimating feed value based on digestibility w/in the target animal
biological analysis
apparent digestibility
digestion trial w/ animals consuming the test ration
nutrient consumed - nutrient excreted in feces = nutrient digested and absorbed
nutrient digestibility %
(nutrient intake - nutrient in feces) x 100
nutrient intake
NRC 8 categories of feedstuffs
dry forages and roughage pasture range plats and green forages silages energy feeds protein supplements mineral supplements vitamin supplements non-nutritive additives
dry forages and roughages
> or = 18% crude fiber (up to 50%) low in NFE (cell contents) variable digestibility and energy content protein content varies (2-30%) CHEAP ruminants and hind gut fermentation -ferment --> VFA's -ruminants forage protein to high quality microbial protein
pasture
grass mixture
variable moisture level (20-80%)
other nutrients vary
moisture content can limit intake
silages
anaerobic respiration produces acids --> low pH -kill microbes and preserves feed loss of nutrients (feeding microbes) can spoil if doesnt stay anaerobic
energy feeds
cereal grains (wheat, oats, corn) < 18% crude fiber high starch low protein (<20% CP) 1st limiting AA -protein quality -grains low in lys, met often low in Ca, P, minerals, Vit A and D
protein supplements
> 20% CP high quality protein EXPENSIVE Plant - oilseed meals Animal - bone, feather, blood, fish meals NPN - esp. urea
mineral supplements
salt (often trace mineralized)
Ca and P from bone meal, oyster shell etc.
premixed mineral “packages”are often purchased
vitamin supplements
yeast extracts, fish oil, etc.
purified vitamins
-vitamin premixes
-fed in excess of requirement as insurance
non-nutritive additives
other ingredients
promote palatability, growth feed efficiency, health
ex: msg, preservatives, coloring, flavor, antibiotics
must be FDA approved if classified as drugs
lasalocid
a cocidiostat
prevents coccidiosis (an internal parasite
increases the efficiency of rumen fermentation
