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186 Cards in this Set

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Pectins - description
v. dig fiber, soluble in hot water, in soft plant tissue, gelling properties
galacturonic acid with monisachharides
Extracellular starch degredation
starch ---dextrins---maltose---glucose
Extracellular cellulose degredation
b(1-4) links hydrolyzed to cellobiose and then to glucose by mo cellulase enzymes
Extracellular pectin degredation
hydrolyzed by pectinases into galacturonic acid units and mono
cell contents
organic acids, sugars, starch, fructans
Middle lamella
pectin
b-glucans
cell wall
hemicellulose
cellulose
lignin
CHO classification by PA
CHO=CF + NFE
est by diff errors
CHO classification NRC
CH0= NDF+NFC
NFC = 100 - (NDF + CP+Fat+ash)
est by diff error
Digested by mammalian enzymes
organic acids
sugar
starch
potentially ferment to lactic acid
sugar
starch
fructans
support mo growth
sugar
starch
fructans
pectic substances
b-glucans
decreased fermentation at low ph
pectc substances
b-glucans
Non-starch polusachharides
b-linked
resist enzymatic dig
mannose, rhamnose, arabinose, xylose, glucose, galactose, glucoronic and galacturonic acids
released by acid hydrolases after amylase trtmnt
starch
a linked
hydrolyzed by pancreatic amylase
water for partitioning NSC
extracts sugars
hot water solubilizes some dxtrins
acetate phosphate buffer for partitioning NSC
extracts sugars
also extracts some poly
pH modifies what they extract
Low molecular weight CHO analysis
reducing sugars extracted with ethanol or water
condensation rxn --simple, fast
enzymatic rxn ---$, more smpl
chromatographic tech--" "
reducing sugar analysis
carbonyl grp reduces alkaline solutions of metallic salts
must hydrolyze all CHO into mono (unhydrolyzed undetected)
protein, ntl reducing agents, alcohol interfere
Enzymatic assay
gluscose hydrolyzed from CHO w/specific enzyme
only detects glucose
Condenstation assay
aka - phenol sulfuric assay
chromegen quantified
phenolic acid+CHO+acid= chromogen
no need to hydrolyze sample
depends on type and pH of acid and temp, and ethanol strength
cellulostic lint interferes
High molecular wt NSC analysis
starch= polarimetry, enzymatic
Soluble fiber
Enzymatic starch analysis
specific enzymes hydrolyze to glucose (determined colormetrcally)
1) gelatinization
2) enzymatic hydrolysis
3) end product quantification
Phosphate soluble fiber
AOAC method
non starch, non NDF = pectin, fructan, gum
1) solubolize CHO in phosphate
2)hydrolze w/ amylogluconidsase
3) filter off insoluble residue
4) precipitaet soluble fiber

ethanol may incolmpletely precipitate soluble fiber and may precipitate other cmpds
phosphate depolymerizes some pstcin
Neutral detergent soluble fiber
extract with ethanol
subtract NDF and starch
est by diff error
High molecular wt NSC
enzymatic starch analysis
Phophate soluble fiber
Neutral detergent soluble fiber
Low molecular wt NSC
reducing sugar analysis
condenstauion rxn
enzymatic rxn
chromatographic techniques
determining mo w/ diet
purified or urea +purified
doudenal protein assumed to be mo
determining mo with fistulatoion
quantify mo in sample
fistulation affects motility and limits replication
rep smapling difficult
correct for dietary and endogenous N
tubidity assesments
increased color depth due to mo growth
mp synthesis in vitro
in vitro ferm - mo harvested
still req fistulation
easier to replicate and sample
measuring MP with TCA
TCA = trichloro acetic acid precipitation
TCA precipitates protein and small peptides
MP=TCA CP in residue - (TCA CP in smaple + TCA CP in media)
measuring mp with markers
internal = DAPA, D alanine, DNA, lipid
external = isotope incorporated into mo matter during growth
complex marker for mo
DNA, RNA
hazardous marker for mo
sulpher, phosphorous, carbon, nitrogen
costly marker for mo
amino or fatty acid profiles
phospholipids
triated leucine
ATP
most commonly used mo marker
D-alanine
puring bases
DAPA
DAPA
aa in bact cell wall
rumen mo have constant DAPA:protein
measure DAPA in dueodenol digesta
assumes all DAPA is mo and constant ration
problems with DAPA
ratio can be affected by morphology of bact, digesta component, time after feeding

DAPA absent n some bact
some DAPA not cell bound
may overetsimate MP
D-alanine
more widely dist in bact than DAPA
part of cell wall peptidoglycans
not wdely used bc a) overestimates, b)may not be valid as a marker
Nucleic acids
RNA: N ratio of duodenal digesta indicates MP synthesis
ratio varies with grwoth rate
requires cannulation
nucleic acids present in feed and tissue
mo nucleic acids may be degraded ruminally
Purine bases/ derivatives
absent in feeds, present in mo
internal marker
assume- dietary purines degraded ruminally, purin:N constant
purine in doudenal fluid MO
but..purine bases may be degreaded in si
use excretory products instead - no need fistula
purine excratory products
allatoin in urine assumed to be mo
cheap, less invasive, less complictaed, easier to anylyze
but..some purines not completelly degraded in rumen, urine collection issues, must account for partioning of allatoin in urine vs recycling
some endogenous secretion from animal tissue
General problems with markers for est MP synthesis
- diff marker= diff result
- no standard
- accurate?
- lack knowledge about proportion of bact types in doudenal digesta
- in vivo marker require cannulation
- rep smapling difficult in vivo
Rumen pH
5 (highly fermentable diet) to 8 (lo quality forage)
< 6 - chronic acidosis
<5.5 = acute acidosis
acute acidosis
rumen stasis, water floods rumen to couter high lactae, kidney , nerve damage, high blood lactae, death
rumen characteristics
anaerobic, low redox potential, lots of saliva as buffer
ferm products
VFA, CO2, CH4, NH3
Rumen mo
bact
protozoa - eat bact
fungi - imp for fiber
mo growth determinants
for maintenance and growth
req - CHO (nrg), N, vita, min
nrg sources for mo
storage and soluble CHO
starch glycogen
rapidly released
nrg sources for mo
structual CHO
cellulose, hemicellolose
slowly released
FME
fermentable nrg
mo cant use
fats, pre ferm cmpds, VFA
silage, growers grain
CH4 and ferm eff
not eff
typical VFA proportions
60% acetate
20% proprionate
15% butyrate
5% other
high roughage and VFA
high acetate
high milk fat
high methane output
high rumen ph
high conc and vfa
high proprionate
high body fat
low ph
high glucose levels
Factors influencing VFA prod
type of dietary CHO
Forage: conc
physical form of diet
level of feeding
freq of feeding
chem additives and ionophoores
VFA absorption
80-90% abs in rumen
10-20% abomasum, omasum
drain to liver via portal vein
nrg from VFA
75% of DE rqmt
Acetate
favored by high fiber diet
abs in rumen
converetd to acetyl co-a in liver
enters TCA cycle
lipogenic
milk fat precuror
Propionate
favored by starchy diet
20% converted to lactate and enters gluconeogenic pthwy
80% abs intact, converted to PEP in liver
glucogenic
Butyrate
favored by high fiber diet
converted to b hydroxybutyrate
measure of ketosis
lipogenic
Methane
favored by high fiber diet
formed from reduction of C02 or acetate decraboxylation
high pr = low meth
pr = H2 sink
inhibited by ionophores
N for MP synthesis
from dietary RDP, endogenous N, recycled urea
NH3 (not protozoa), free aa, peptides, fatty acids
Yatp
relates amt of mp produced to ATP req
varies with bact type, substarate, and mo nrgy req
factors influening yatp
composition of diff cells
nut supply
nrg used for nut transport
maint req of cells
synchrony theory
sychronizing the supply of dietary N and nrg imporves eff of mp synth
straw + urea
N quick release
high blood urea (hyperexcitability), N loss in urine
NH3 wasted, MP synth reduced
corn + SB
nrg quick release
risk of acidosis
NH3 wasted, MP synth reduced
grass hay + SBM
ideal
NH2 reduced
MP optimized
problems with synchrony theory
- bact can make and store starch
- does not always improve eff
balane may be better than synchrony
Factors affecting eff of MP synthesis
-dietary P and nrg source
- ruminal P and nrg balance
- ruminal outflow rate
- feeding level and rate
- ph
- min and vit availability
- recycling of bact N due to bact lysis and protozoal predation
Zero grazing criteria
rep. grazing conditions
freq feeding
collect and analyze refusal
feeding level choice
zero grazing pro and con
pro - easy to replicate, ideal for conserved forage

con - selection reduced, affected by wilting/deteoration, labor, no competition effects, no sward structure effetcs
Electronic gates
calan gates
broadbent gates
pro - allows single animal to designated manger, social interaction, excercise, no confinement

con - cost, train animals, stealing, circuit failure
continous reading mangers
hoko feeders
mangers on pressure sensors, measure wt changes, intake kinetics (meal patterns), smae pro and con as calan gates
perforate sward boards
what and how quick
pro - allows precise sward description, indicates bite area and depth

cons - short term, representative?
Turves
wiehg and measure, offer tray to animal, reweigh and measure

pro - accounts for sward structure, less deteroiation of forage

cons - short term, rep?
Grazing cages
pro - account for sward structure

con - time consuming, short term, rep?, no competition
herbage mass measurment
esclusion cages
sample cuts from within cage
pro - no animal handling
con - need uniform height and surface
intensive smapling
short term
trampling, fouling, rep?, soil contamination
Short term BW measurements
wiegh, graze, weigh
account for fecal and urine losses
pro - longer than sward boards and turves
animals graze real pasture
con - watre intake and insensible loss quantification
environmnet affects results
non forage intake needs to be accounted for
measure grazing time/behavior
watch and record # bites
pro - wild and domestic
con - observer may affect behavior, short duratio, subjective, assumes bite mass constant
vibracorders
like truck tachographs
measures time head lowered
cons - equip may affect ntake
head low may not = biting
jaw recorders
differentiate rumination from eating
con - may not work on some cows
equip affect intake
total feces collection
pro - gives individual intakes
req only dm and ash determination
cons - bags may affect intake, lose some fecal matter on low DM diets, better for sheep (drier feces)
Markers for intake
dose and collect samples
internal markers
lignin, AIA, silica, fecal N, indigestable NDF, chromogens
must get rep sample of what grazed
internal marker problems
silica incompletely recovered and infl by soil contam
lignin subject to diurnal variation
iNDF incompl recovered
chromogens not good for drought stresses pastures
AIA low in forages = need lrg samples
lignin depends on what is eaten and when its eaten
external markers - chromic oxide
pro - ind intake, suitable for long term studies
con - carcinogenic, daily dose = labor and stress, lrg diurnal variation if only dosed 1x/dy, continous release devices may not be reliable
markers - alkanes
main component of plant surfae wax
inert, easy to use and anylyze
plants have high levels of odd chained alkanes and low levels of even chained alkanes
profile of each plant unique
odd - internal
even - external
dose with both and measue
alkane pro and con
pro - indv intakes for various spp.
slow release bolus only give 1x
con - lab analysis, relies on accurate alkane extraction, and rep smpling
fecal index methods
based on inverse relationship bw fecal N and digy
diff eq needed for diff species
In vitro pasture quality analysis
tilley and terry
pepsin cellulase
NIR
rumen simulation
In vivo pasture qual analysis
dacron bags
whole tract digy
n-alkanes (C36)
diet selection includes
plant community, idividual plant, part of plant
factors affecting diet selection
- animal: species and size, gut type, mouth morphology, physiological state, parasite burden
Forgage: leaf:stem, weeds, sward structure
Environment: social and physical
snip samples
est diet comp
pro - quick and cheap
con - difficult to mimic grazing
Cages
est diet comp
compare forage under exclusion cage w/ grazed pasture
pro - accurate
con - cages dont suit all veg type
# of cages req for patchy sward
N-alkane methods
est diet comp
plant finger print
anylyze feces/ esophageal samples and hand plucked samples
pro - useful if #alkanes>diet componnets
con - complex math, must know alkane profile, alkane content varies with plant parts and soil type
Fecal analysis for est diet comp
examine fecal samples under microscope for plant tissue fragments
pro- minimal dist of animals
animals can be free ranging
con - not accurate, under est dig and over est undig
GIT tract analysis for est diet comp
kill animal collect samples from rumen and gut
pro - if animal will die anyway
con - only est what last eated, cant repeat, partial dig may affect results, depends on indv animal metabolism
Surgical modification for est diet comp
collect samples from fistula
pro - repeatable and accurate
con - ethical, short sample time, assumes behavior of fistulates is same as normal animal
Nut value of tropical grasses
low CP, low sugar and starch, high NDF, high lignin
method of imporving forage quality
1) improve forage: breeding, proceesing, chemical trt, enzymes, innoculants
2) provide missing nut: increase amt offered, supplememt conc, byproducts, intercropping
Criteria for assesing trtmnts
economics
effectivness
saftey
availabilty/ feasabilty
infrastructure
breeding for imp qual
effective but slow
extensive reseeding req
processing for imp qual
effective for mature poor qual forage
chop, grind, pellet
less sorting, increased intake, easy handling, increased surface area
fine ground and gut fill
less sorting, less gut fill, higher passage rate, higher intake, lower digy
unprocessed and gut fill
high gut fill, low passage rate, low intake, more sorting, low performance
dangers of excess processing
reduced effective fiber content
rdeuced fiber dig
decreased salivation
acidosis risk
low acetate = low milk fat
increased maillard products
steam trtmnt
bioconversion of lignin to cellulose
disrupts cell wall
solubolizes cmpnts
excess= dry matter loss
too$ for animal feeding
chem trt
oxidizing agents
solubilize lignin
too expensive
chem trt
hydrolytic agents
more effective on monocots
incl ammonia, urea, urine, CaOH, NaOH, KOH
NaOH trt
widely used
disprupts linkages, partially solubolizes hemicellulose and lignin
soak - pollution
spray - less effective
pockets of high NaOH = caustic soda
Ammoniation
most wiely used in US
less effective than NaOH
increases TDN and CP
hazardous
pro - decreased mold, increase digy an p
con - $, avialbility, corrosive, dangerous, bovine bonkers if not mixed, need CP:S = 10:1 S for S aa
from natl gas = $$
Urea
converted to ammonia by plant urease
safer but more variable than ammonia
must use feed grade
need moist forage
no handling or applicatio problems
Urine
increase digy
collection problems
health
mold
Fungal trt
fungi solubolize lignin
big increase in digy
also lose substrate (incl CHO)
enzyme trt
hydrolyze polysaccharides
increase intake
increase rate but not extent of dig
most effetcive when applied to high quality forages fed to stressed cattle
mixing forages
increases intake and imprives performance
supp
biprod and forage supp may be cheaper and more effective than con
trans$ for conc
antinutrient definition
subs which either by themselves or through metabolic products interfere with the food utilisation and affect the health and production of animals
characteristics of antinutrients
products of 2ndary metabolism
in all plants to some degree
common in tropical forages
defensive role
may be immunosuppresive
glycosides
bitter
CHO and non CHO moiety
toxicity results from aglycone release during enzymatic dig
linssed, cassava, sorghum, clover, soya
phytoestrogens
glycoside subgroup
female sterility
estrogenic activity
male sterility
sapponins
glycoside subgroup
foaming
bloat, haemolysis, GIT erosion, inhibit enzyme action
alkaloids
basic, bitter, toxic, potent
cocaine, nicotine, caffeine
lupins, potatoes
kidney, pulmonary, liver damage
diarrhea
Protease inhibitors
inhibit GIT proteolytic enzymes
pea, bean, soya, potatoe
competitive inhibition
N retention
reduced groeth rate
Lectin
high molecular weight glycoproetin
beans
mucosla erosian in SI
Mimosiene
non proetin aa
leucaena leucocephala
goiter, alopecia, anorexia, gastroenteritis, hepatotoxicity
inactivated by s.jonesii
oxalate
metal ion scavanger
cause ca def
urinary calculi and oxalate crystals
rumen stasis, hypocalcemia, renal failure
phytases
metal ion scavenger
Zn, P, Mg deficiency
Glucosinolates
kale, rape, linseed
thyrotoxic, milk taint, goiter
mycotoxins
moldy feed
hemorrhagic bowel syndrome
tannins
form complexes with proteins, cho, minerals
grapes, wine, tea, fruit juice, cider, trees
high in tropical browses
hydrolyzable tannins
anthocyanidins
water soluble
can be toxic
condensed tannins
proanthocyandins (PAs)
less toxic
widespread
form strong H bonds with nutrients
effect of PA depends on
concentration and properties
animal spp
protein conc
ph
tannin binding agents
negative PA effect on forage qual
reduce VFI
reduce digy
erode gut lining
toxic
positive effects of PA on forage qual
increased eff of protein utilisation
reduce parasite burden
reduce proteolyisi during ensiling
prevent bloat
increase qual of animal products
defaunte rumen
reduce N emmision
General prob of feed analysis
- unrep sampling
- sample deterioration in transit/ storage
- outdates, innacuare mthods
- intra vs inter lab variation
- lack of validation before adoption
- misuse of equations
- disemnetaion of biologically unmeaningful results
consequences of wrong results
- wasted time, $, effort
- reduced profits
- compromised animal productivity and welfare
- litigation
Reason for discrepency
Analytical: sampling, storage, procedure, reagents, calculations, equip, terms and units
Human: attention, skill, expertise
Random
Good labs should
monitor precision, accuracy, repeatability
validate with in vivo
enforce quality control
calibrate and standarize with regularity
ensure health and safety in workplace
Association of Official Analytical Chemists
AOAC
monitor precision, repeatability, reproducability
NDF - not approved
National forage testing association
certifies proefciency
voluntary
only DM, CP, ADF, amylase NDF
constraints to standardization
"my way is best" mentality
need to change procedure or equip
who will monitor
what penalties for offenders
and how will they be enforced
precision
same result again and again
depends on sampling and analytical error
accuracy
truth
degree of conformity with standard
depends on appropriatness of method for acheiving result
use check or standard sample
predictor
independent
predicted
dependent
consideration for predicting nut value
lrg population
valid relationship
critera for choosing a predictor
biologically meaningful
rapid and easily determined
inexpensive to anylyze
repeatbale
precise and accurate
ethical
correlation coefficient
measures only linear association
does not reflect causation
coefficient of determination
r2
does not imply cause
residual standard deviation
important for measuring error
factors that affect prediction relationship
spp
site
plane of nut
latitude
season
maturity/regrowth
fertilization
ferm
processing
empirical
may be accurate but not bio meaningful
summative
empirical est with bio meaning
mechnanistic models
explain underlying mechanisms
complex
computer computations
costly
benefits of decreased forage:conc
increased ruminal nrg release for mp and fiber degredation
decreased limiting effect of proprionate def on fiberous diet intake
increase conc beyond 60% DM??
no - dpress intake, acidosis
associative effect
interaction bw nut in ration which cause a higher or lower performance than expected for individual ingrediants
may be positive, negative, or absent
positive assoc effetcs
increased fiber utilisation after N supp on N def forages
increased fiber utilisation after supplementeing roughages with sugar
increased intake
increased mp due to synchrony/balance
ex) high NSC and RDP forgages
may redce need for supp
negative assoc effetcs
more than 60% conc decrease fiber utilization
fat supp> 5-6% reduces intake and coats particles = prevent ferm
presence of antinutritive factors
factors determining assoc effect
palatibilty of ingrediants
nut content of ingrediants
nutrient fractions
physical form of feed
mo activity
nrg:P
sub rate of conc for forages
level of feeding
passage rate
Silages
- anaerobic storgae of high moisture forage
- 20-40% DM
imp for dairy cows
types of silage
cereal: frem CHO and fiber, palatible
Temp grass: high NPN and sugar, low NDF
trop grass: poor ferm, high NDF, low sugar
Legume: difficult b/c buffering capacity, high CP
Haylage: high DM grass, in bales, may benefit from additive
chem changes during ferm
sugars ferm into VFA
low pH
protein degraded into ammonia and NPN
Homolactic ferm
v. desiarable
sugars into lactic acid
lactobacillushigh sugar grasses
heterolactic ferm
undesiarble
brevis, buchnerii
sugar to acetic, alcohol. butyric
high ph allows secondary ferm
secondary fermentation
degredation of lactate by clostridium to ac and bu
high moisture and high pH
Aerobic spoilage
sig loss of nut
casued by aerobic sugar and lactate utilizing yeasts and molds
heat production denatures protien
preventing aerobic spoilage
proper packing
manage silo face
additives
silage additives
direct acidifers: acids to lower ph - sulpheric
ferm inhibitors: lower ph, inhibit microflora, formaldehyde
ferm stimulents: substrate for ferm (molasses), enzymes to speed up, mo innoculants
specific antiobio
problems with additives
snake oil
lack of scientific eveidence
nut targets for grass silage
30% DM
avoid prolonged wilting or execess moisture
3.8-4.2 pH
ammonia N <50g/kg
>10.8ME
>700 DOMD
bucherii
higher acetic acid
sweet smell
not good
high ethanol conc
heteroferentative pthwy
proliferation of yeasts
sig DM losses likely
vinager smell
acetic acid
heterofermentative pthwy
antifungal = aerobically stable
may reduce intake
tobacco/molsasses/burnt smell
protein dmage
maillard rxn
N wastage
foul fishy smell
butyric acid
clostridial 2ndary ferm
excess moisture
poor nut value
moldy musty smell
aerobic spoilage
possible mycotoxins
inhaliation risk
no smell
lactic acid
desiarable
BOD
amt of )2 req by aerobic mo to decompose organic matter
measures water pollution
silage effluent major contributer