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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

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