Nutrition Exam 2

nutrient categories in feedstuffs:

• H2O

• energy (carbs and fats)

• protein

• vitamins

• minerals

energy in feedstuffs

Kcal

Mcal

TDN ( total digestible nutrients)

protein in feedstuffs

crude protein

in ruminants —>

• degradable intake protein = used by rumen microbes (transformed)

• bypass protein (undegradable) = remains available for SI digest and absorb

which type of protein is important to meet intake needs of dairy cow?

bypass protein!!!!

feed analysis

components measured —>

• dry matter (DM)

• ash (minerals)

• crude protein

• fiber

• non-structural carbs

only compare feedstuffs/ingredients on a ____ ____ basis!

dry matter

animals eat to meet dry matter intake (DMI)!!!

% H2O in pasture, hay, and silage

pasture = 70-80% H2O

hay = 10% H2O

silage = 50-70% H2O

plant structure and digestibility has 2 components:

1) cell walls

2) cell contents

cell contents contain:

very digestible (sugars, starch, proteins)

cell wall contains:

structural (cellulose, hemicellulose, lignin)

fiber =

general term for plant cell wall components (cellulose, hemicellulose, lignen)

• resists enzymatic digestion

• ruminants require microbial fermentation

order of fiber digestibility:

hemicellulose —> cellulose —> lignin (indigestible)

more mature plants have more:

lignin = as lignin increases, digestibility of cellulose decreases

methods of measuring fiber:

NDF (neutral detergent fiber) = predicts intake (cellulose, hemicellulose, lignin)

ADF (acid detergent fiber) = predicts digestibility (cellulose, lignin)

NDF represents:

total cell wall content

predicts voluntary feed intake

increased NDF —> increased satiability —> decreased intake

what do we like to see with NDF?

<40% NDF = excellent

40-45% NDF = good

> 65% NDF = poor intake likely

ADF represents:

cellulose + lignin

predicts digestibility and energy value

increased ADF —> decreased digestibility

what do we like to see with ADF?

30-35% ADF = good quality

> 45% ADF = poor quality

non-structural carbs (NSC) =

soluble component of plant cell contents

consists of simple sugars, starch, and organic acids

can be digested by enzymes (amylase)

v important in horses!!

plant maturity… what tf happens?

fiber increases

protein decreases

energy decreases

digestibility decreases

sooo timely harvesting affects forage quality

why does fiber increase as plants mature?

because of increased lignification of cell walls!

forage types:

grasses

legumes

forbs

* grasses and legumes are majority of livestock forages

grasses:

decreased protein (as compared to legumes)

increased fiber

ex: bermuda grass, rye, timothy, fescue

legumes:

fix nitrogen in soil

increase protein and calcium (as compared to grasses)

ex: alfalfa, clover, soybeans

improve pasture nutritional value!!

types of tall fescue (grass)

TE fescue (toxic endophyte)

EF fescue (endophyte free)

NE fescue (novel endophyte)

what is an endophyte?

acremonium coenophialum; produces ergot alkaloids

issues/toxicities of ergot alkaloids

vasoconstriction, hypersensitivity, impaired heat stress recognition

issues/toxicities of fescue

fescue foot (gangrene) in cows

summer fescue toxicosis in cows

prolonged gestation, weak foals, abortion, agalactia (low milk) in horses

issues/toxicities of perennial bermuda

dense roots that spread through rhizomes and stolons

become extremely fibrous when over-mature (pokes mouth and GI tract)

issues/toxicities of perennial ryegrass

ryegrass staggers (fungal endophyte in seeds produces peramine and lolitrem B)

facial eczema (saprophytic fungus on dead plants produces sporidesmins)

issues/toxicities of annual ryegrass

annual ryegrass toxicosis (seed gall nematode infected by seed gall bacteria which produces corynetoxin)

issues/toxicities with alfalfa

bloat (cows)

blister beetle toxicity (horses)

• contain cantharidin leading to oral ulcers and colic

issues/toxicities with sweet clover

high in coumarin (converted by mold to dicoumarol - anti-vitamin K (affects clotting))

issues/toxicities with red clover

slobbers (slaframine)

issues/toxicities with alsike clover

acute = photosensitization in horses

chronic = liver failure and neuro impairment

issues/toxicities with white clover

contains cyanogenic glycosides that produce HCN (detox can inhibit iodine binding in thyroid!)

Pasture management

Use rotational grazing to prevent overgrazing (increase carrying capacity and pasture longevity)

Maintain appropriate stocking rates

Mowing fertilizing and weed control improve pasture

Concerns with pasture

Toxic plants

Bloat (legume rich)

Nitrate toxicity (drought)

Hay (dried forage) characteristics

Long fiber

Reduced moisture (15-20%)

Fire risk!

What causes hay loss

Leaf shatter during raking

Fermentation (sugars and starches —> co2 + h2o) = decreases energy content

Bleaching = decreases vitamin A

Heat damage ( greater than 120 degrees F leads to nutrient loss)

Preservatives

Methods allowing for storage at higher moisture

• propionic acid

• Formic acid

Chemical treatment of low quality hay causes risk of

Bovine bonkers because ammonia and sugars causing nervous system impairment

How to chemically treat low quality hay

Anhydrous ammonia (increases digestiblity by dissolving lignin and nitrogen content)

Silage (haulage/baleage ) is:

Forage preserved by fermentation under anaerobic conditions

How much moisture in silage?

High moisture

How much moisture in haylage/baleage?

Intermediate moisture

Process of creating silage

Forage chopped and tightly packed

O2 removed (important for anaerobes and inhibits mold)

Microbes ferment sugars—> lactic acid (decreases pH from 6-4.2)

• if pH rises; listeriosis and botulism can occur

Storage of silage

Silo!

Upright

Horizontal (trench/pit, piles, bags)

Moisture goal for silage

50-70%

Penn state forage particle separator

Separates silage components by particle size

Indicates quality (particle size determines fermentation rate, rumination, and digestiblity)

Protein concentrates

Oilseeds

Seeds are high in oil and protein (cottonseed and soybean)

Oil extracted for human use, leftover is high in protein -meal

whole soybeans must be heat treated prior to consumption because they contain:

trypsin inhibitors = decrease protein digestibility and cause allergic rxn in young creatures

lectins = bind carbs

phytoestrogens = mimic estrogen (antagonists)

stems and leaves of oilseeds and cereal grains=

roughage

soybeans most commonly used as protein supplement in:

poultry and swine

whole cottonseed is used in the:

dairy industry

risk of gossypol toxicity

yellow compound in cottonseed

heart, lung, repro toxicity

swine affected most, then poultry, then pre-ruminants, then immature ruminants (mature ruminants are not susceptible)

what is protective from gossypol

iron salts and high protein - binds gossypol

heat processing - inactivates it

cottonseed meal is low in lysine and good for which species?

ruminants

rapeseed contains:

glucosinolates = inhibits thyroid gland = goiter

canola

rapeseed hybrid

low in glucosinolates!!

energy concentrates =

cereal grain

includes seeds from grasses (high in energy and starch!)

corn

• highest in energy

• low crude protein (lysine and tryptophan are limited)

• requires processing to be well utilized

• mycotoxins (mold) is contamination concern

  • alfatoxin produced by aspergillus spp.

sorghum

drought resistant!

contains tannins in outer layer; react with GIT enzymes = heat treat!!! to decrease tannin digestibility

wheat

increased digestibility and CP

decreased fiber

risk of acidosis in cows b/c highly fermentable!

• limit to <50% of grain intake

barley is grown where

north

what must you do to barley

grind/roll/flake b/c of hard kernel

oats are grown where

cold and wet climates

how do you feed oats

whole or rolled

increase soluble fiiber which decreases colic

concentrate byproducts

brewers and distillers grain =

rich in vitamin B

devoid of most sugar/starch b/c fermented for alcahol

suitable for ruminants

beet pulp =

residue post sugar extraction

12% CP

45% NDP

20% CF

palatable and soluble fiber

good for horses!!!!

molasses is

by product of sugar beet or sugar cane

reduce dust

distillers grains =

residues of grains fermented = liquer

brewers grains =

barley fermented = beer

meat and bone meal

cannot feed to ruminants because of risk of BSE

poultry litter

ew

bedding material, feathers, droppings, spilled feed

increase in NPN

used in ruminant feed

salmonella risk

oils and fats (tallow):

decreases dust in feeds

increases palatability

equine digestion facts:

• small stomach (require frequent feeding)

• no gallbladder (continuous bile secretion)

• hindgut fermentation (cecum and colon) - 80% of GIT capacity

• produce VFAs

• continuous tooth eruption (hypsodont)

where do horses digest hydrolizable carbs?

SI

where do horses digest fiber?

hindgut fermentation (cecum and colon)

where do horses digest protein?

SI (high quality protein) and LI (low quality protein)

what are non-structural carbs?

simple sugars, starch, fructans

what are the hydrolyzable carbs and where are they digested?

sugars and starch —> digested in SI

What are the rapidly fermentable carbs and where are they digested?

resistant starch and fructans —> hindgut digestion

what are the slowly fermentable carbs and where are they digested?

cellulose and hemicellulose —> hindgut digestion

what are the structural carbs and where are they digested?

fiber —> hindgut digestion

equine feeding strategies:

pasture —>

most natural

mixture of grass and legumes

when can horses meet daily grazing intake on pasture?

w/in 4 hours

when is just pasture feeding not sufficient?

for growing foals, lactating mares and training horses

how should hay and grain be fed?

meal feeding

it’s ideal to use what kind of grazing?

rotational grazing!!!

what should you maintain pasture grass length at?

4-8 inches

evaluating pasture adequacy - what are the 2 important steps?

monitoring BCS

Forage analysis

what all is part of a forage analysis?

pasture vs. hay

is DE sufficient

are nutrients in correct ratios

what is NSC (concern for laminitis and colic)

interpreting a forage analysis

2 solumns

1) as-sampled

2) dry matter

measures cp, fiber (ADF, NDF, lignin), energy (DE and MCal), WSC (water soluble carbs), NSC (WSC & starch) and relative feed value (RFV)

Relative feed value (RFV)

ranksforage on ADF and NDF compared to alfalfa, provides hay intake exception

hay is fed by what?

weight not volume

fed in bales, nets, on the ground

feeding method affects waste and intake

grain is fed by what?

fed by weight, not volume

feed individually if possible

store in creature tight (possums transmit sporocysts causing EPM), moisture tight, and keep containers off ground

dry matter and as-fed calculations:

DM —> concentration of nutrients (%) is higher; nutrients in diff diets must be compared on a DM basis!!!

AF —> mixing ingredients for a diet determining a final amount to feed must be done on AF basis

what constitutes good quality hay?

green

leafy (low stem)

free of mold/dust

no weeds or foreign materials

dry matter intake (DMI) what we need to:

feed consumed exclusing H2O —> determines nutrient intake

maintenance = 1.5-2% BW; growth/lactation = 3-3.5% BWof an animal's body weight; essential for assessing nutritional needs.