composition of feedstuffs Flashcards
How do u assess the quality of feed
- quantity of nutrients: measure gross energy or animal
- availability of nutrients
- degradability of nutrients - how quick there available
- balance of nutrients
- capture of nutrients: how much of the nutrients are obtained by the animal.
what is energy/ where does energy supply come from in ruminants diet?
energy is the first limiting nutrient
what are the two groups of carbohydrates?
- simple sugars and starch
- Cellulose/ hemicellulose
what are simple sugars and starch
and give an example
soluble or storage carbs
E.g cereals
what acid is produced in the rumen from simple sugars and starch
lactic acid
- altered pH and microbial flora, acidosis, indigestion and low fat milk syndrome
What are cellulose/ hemicellulose
and give an example
structural carbs
- slower breakdown
example: Forage
what are major end products of digestion
Volatile Fatty Acids
- Acetic, Propionic, Butyric
- they are absorbed through the rumen wall
Are Neutral Detergent Fiber (NDF) soluble or insoluble?
insoluble
what are fats
fats are energy dense
approx how much more energy is in fats than carbs
2-3 times
what can fats cause
Digest upset
- cellulolytic
- fibre digestion
What are the benefits of fat
fats have a negative impact on methane production
what is the % fat level in
-Grass
- Perennial Rye Grass
grass: 3-5%
PRG - 8%
What is simplest system for approximation of analysis
proximate analysis
how does proximate analysis work?
all nutrients should be expressed as kilogram of DM
- Usually it just moisture is removed when finding DM but with silage volatile acids are also removed
what is the % ash content of silage
7-10%
- if higher it indicated soil contamination during harvesting
how digestible is:
Hemicellulose:
cellulose:
Lignin:
Hemicellulose: highly digestible
cellulose: moderately digestible
Lignin: completely indigestible
what happens when lignin increases?
it interlinks with cellulose and hemicellulose making them less digestible
what does lignin do?
gives strength and rigidity to plant cells particular to stem on plant
What is ADF
Aciddetergent fiber
-cellulose in lignin (least digestible)
what is NDF
cellulose and hemicellulose
what is physically effective fibre
ruminants require fibre in coarse physical form
what is Physically effective NDF (peNDF)
the fraction of fibre that stimulates chewing activity and is primarily related to the particle size
- enhances saliva flow, acetate to propionate ratio, milk fat levels and maintains the rumen pH
what has a positive impact over rumen performance
an appropriate level of NDF and the particle size in the ruminant diet
- it increases the dry matter intake and its digestibility
According to National Research Council(NRC), what should NDF content be maintained at of dietary dry matter
with what % from forage
maintained at 30% of dietary dry matter with at least 21% from forage
what is the Gross Energy value of feedstuff?
17-18.5 MJ
What is Digestible energy
energy that is not lost in the faeces
- good in monogastric
- useless in rumens: doesn’t consider methane
how much Gross Energy is lost as urine
3%
What is Net energy
what’s available for maintenance and then what’s available for animal products
what % of GE will be Net energy
40%
common forages for ruminants
Grass: PRG, Timothy
Legumes: clover. peas, vetch
Herbs: chicory, plantain, sheep’s parsley
Brassicas: rape, kale, turnips, swedes
what units are used to measure Net energy
UFL - Cows
UFE - cattle
what is nutrient availability influenced by
degradability
what may help improve nutrient supply and animal performance
including alternative species
Low protein feeds
cereals (main feed)
- feeding high levels of cereals can cause acidosis
beet pulp/citrus pulp
soya hulls
molasses (lots of energy, not much protein)
what is the fuel supply of cereal grain
endosperm
where in the protein in a wheat grain
embryo/germ
what are the major cereals
-barley
-wheat
-oats
-maize
-rice
-rye
what are cereals low in?
- low in crude protein (low in essential amino acids)
- fibre content low
- oil content low (mainly saturated) : 10-12 g/kg to 40-60 g/kg
- Ca content low(1.5 g/kg
- Vit A & D
what are cereals high in
Phosphorus
Vit E
Thiamine
by products of sugar and citrus fruits
Beet pulp
molasses
citrus pulp
medium protein feeds
corn gluten
peas
maize distillers
beans
palm kernel
cereal by- products
-from brewing, malting ,milling
-starch removed
-feeding value more reduced for monogastric than ruminants
- quality can be variable
high protein feeds
soyabean meal
cottonseed
rapeseed mean
sunflower meal
main oilseeds by products
soyabean cottonseed
rapeseed
sunflower
-grown from oil: high in oil and protein
- can contain toxins/ANF’s
Soyabean Meal
- oil solvent extracted and meal subsequently toasted
what does raw soyabeans contain
goitregens
protease inhibitor
what is soyabean meal low in
methionine
cysteine
lysine
where are soyabean meal sourced from
US or Brazil
rapeseed meal
oil extracted by prepressed solvent extraction
- good amino acid balance in protein
-consistent in quality - ANF: Isothiocyanates and goitregens
Cottonseed Meal
- Very variable
- may contain gossypol (anti-oxidant)
-Sourced from Africa, China, Argentina, Uzbekistan
Sunflower Meal
-very variable
- inversely related to fibre content
- mostly solvent extracted
-good quality protein
- Sourced: Europe, south america
most variable feeds
cottonseed meal
malt combings
sunflower meal
pollard
maize distillers
- home mixers beware: test batches
