Diary cattle nutrition Flashcards
___ % is small intestine
20%
___% is cecum
3%
___ % is large intestine
9%
NDF
structural CHO: hemicellulose and cellulose (cell wall + lignin)
ADF
cellulose
nonstructural CHO include
cell contents: organic acids, sugars, starches, fructans, pectic S, B glucans
_____ come together to create VFA in rumen
fiber and starch
net energy feed values table
?
lipid digestion in ruminants
lipid to glyceral to VFAs
or lipid to SFAS
or lipid to UFAs to SFAs (biohydrogenation
SFAs and UFAs are
excreted into small intestine
vitamine A (retinol)
absolute requirement
Vitamin D (cholecalciferol)
synthesized by ultraviolet radiation of the skin, but is typically also supplemented to dairy cows
Vitamin E (tocopherol)
absolute requirement
Vitamin K (phylloquinone)
synthesized by ruminal bacteria to meet requirments
ruminal bacteria synthesize most ___ vitamins
water-soluble (so true deficiencies of these viamins are rare)
there are some benefits to supplementing ___
niacin and biotin
water-soluble vitamins include
thiamine nicotinic acid pantothenic acid choline vitamine b12 riboflavin pyridoxine biotin folic acid vitamin C
water intake increases with
milk production and temperature
to meet nutrient demands of high-producing dairy cow:
increase DMI
increase nutrient density of diet
dairy cow phase 1 (early lactation)
0-10 weeks
peak milk production occurs wihtin 3-6 wks
phase II (mid lactation)
10-24 weeks
milk yield begins to decrease, peak DMI occurs within 11-1 wks
phase III late lactation
> 24 weeks
milk yield continues to decrease; cows regain body tissue reserves
phase IV dry period
5-8 wks dry period, late pregnancy (rapid fetal growth)
phase V transition period
2-3 wks
dry period; late pregnancy; prepare for lactation
dairy cow production stages chart?
x
physiologic priority during phase 1
lactation
reproduction
growth
maintenance
physiologic priority during phase 2
reproduction
lactation
growth
maintenance
physiologic priority during phase 3
reproduction
growth
maintenance
lactation
goal of feeding dairy cows
provide high energy diets to allow cows to achieve their genetic potential to produce milk
dairy cow dilemma
feeding high-grain diets= more milk, but too much dietary starch may damage rumen papillae (parakeratosis) and depress milk fat due to inadequate intake of dieatry fiber
challenge of dairy cow feeding
feed diets with sufficient energy to support maximal milk production while maintaining adequate dietary fiber levels to avoid rumen damage and milk fat depression
impact of type of diet on rumination time, saliva production and rumen ph
more salivation and rumination causes more alkalotic rumen PH; small difference in PH will have huge difference on microbes
starch loving microbes
increase with increase in grain (get more propionic acid)
fiber loving microbes
increase with increased roughage diets; (more acetate less proprionate)
acetate is needed for
milk production
how does inadequate dietary fiber level depress milk fat synthesis?
increase grain provides for starch loving microbes increase lactic acid production (decrease ph) increase starch loving microbes more decrease fiber loving microbes decrease rumination time decrease production of saliva decrease dietary fiber digestion decrease acetic acid production decreae milk fat synthesis
how do we maintain adequate fiber levels in lactating dairy cow diets
- formulate diet to contain a minimum forage: concentrate ratio of 40-60
- formulate diet to contain minimum of 17% crude fiber or 21% acid detergent fiber (adf more accurate measure of fiber content of feed)
- feed minimum of 1-1.5% body weight as a forage
rules of thumb that do not always work
x
ROT: better to consider ____ level of the diet, not just total fiber level
effective fiber level
ROT: effective fiber is defined as
the properties of a feed that cause a cow to chew
ROT: the higher the effective fiber in a feed,
the more time a cow will spend chewing and or ruminating
effective fiber of a feed is dependent on
particle size (long stem vs pellets) amount of fiber (FC, ADF, or NDF) type of fiber (proportion of lignin)
roughage value index (RVI) is determined by
measuring the amount of time a cow spends chewing
RVI is expressed as
minutes per chewing per unit of feed DM
roughage value index in order from least to greatest
barley grian,alfalfa pellets, corn silage, long stem alfalfa hay, med. quality hay
what is a method to measure effective fiber
penn state particle size seperator
impact of particle size of ration on performance of lactating dairy cows
fine particle size caused cows to ruminate less, produce less saliva and favored microbes that produce starch
short term benefits of including adequate levels of effective fiber in the lactating cow diet
chew more and provid emore saliva based bufferes to the rumen which will increase rumen ph and provide an environment more faborable for fiber-loving microbes; increase acetic acid production which is the precursor of milk fat synthesis
long term benefits
help maintain integrity of the rumen epithelial tissue thus preventing rumen parakeratosis (rumen burnout)
other nutritional factors that will affect milk consumption
type of grain
grain processing
dietary buffers
types of grain
cows fed grains which have a faster rate of rumen starch fermentation are more likely to have depressed milk fat
wheat>barley>corn and milo
grain processing
the more a grain is proessed the faster the rate of rumen starch fermentation
(steam flaking> cracked or dry rolled > whole)
dietary buffers
adding buffers to diet will increase rumen ph and help to minimize milk fat depression
dietary fats
adding fat to the diet may decrease milk protein
rate of starch fermenation differs by grain source
wheat most rapid
barley intermediate
milo less rapid
corn less rapid
the more you process grain,
the more rapid fermentation more likely you will have acidosis
sodium bicarbonate can be added to the diet at ____ of diet dry matter
1%
situations when dietary buffers are beneficial
high cornsilage based diets high grain diets low effective fiber diets heat stress when cows are off feed (early lactation)
energy density of the diet can be increased by
replacing a portion of the grain in the diet with fat
fat added diets allow more energy intake while avoiding
excess starch or low fiber intakes
including more than 8% fat in th etotal diet will cause
DMI to decrease
fiber digestion to decrease
incidence of digestive upsets to increase
most grains and forages contain ____ fat
3%
therefore, fat can be added to diets at ___ without adverselyaffecting DMI or digeestibility
5%
high producing cows within the first ______ of lactation benefit most from fat-added diets
2-5 months
cows fed fat-added diets typically produce ___ more milk per day
4-6 lbs
cows fed fat-added diets lose less weight during
early lactation
____ cows eat less and produce less
heat stressed (>80F)
feeding fat-added diets to heat -stressed cows is beneficial because
heat increment is decreaed
feeding fat-added diets may _____ the incidence of ketosis and _____ reproductive performance
reduce
enhance
sources of fat for lactating dairy cows
plant oil seeds
unprocessed fat sources
processed fat sources
plant seed sources
cottonseed
soybean
canola
unprocessed fat sources
tallow
hydrolyzed animal-vegetable oil blends
processed fat sources
Ca salts of fatty acids
prilled fat
rumen inert fats (bypass fats)
do not disrupt rumen fermentation of fiber like unprotected fats (tallow)
rumen inert fats help maintain
BCS during negative energy balance when dry matter intake is limiting
increasing the energy density of the ration helps minimize
rebreeding problems, maximize milk production and maintain body condition
traditional feeding system
forage and concentrate based feeds are fed separately
steps to traditional feeding system
determine nutrient requirements
estimate forage DMI
estimate forage nutritional quality
challenging to formulate concentrate mix to supply nutrients beyond what the forage provides
total mixed ration feeding system
forages and concentrates mixed fed together
steps to tmr feeding system
determine nutrient requirements
estimate forage DMI (easy cause not grazing)
estimate forage nutritional quality (easier for harvested forages)
formulate TMR
advantages of using a TMR feeding system
cows not permited to eat fav forage
cows forced to eat correct balance of forage and concentrate
numerous meals throughout day; helps maintain ph
easier to feed cows in variouus groups
reduce incidence of social dominance
advantages of using traditional feeding system
harvesting and chopping forages for TMR system is expensive
costs of grazing forages as part of traditional system is cheaper
cost of feeding equipement for traditional system is less expensive
BCS 1-1.5 dairy cow
severe under condition
BCS 2-2.5
thin
BCS 3-3.5
moderate
BCS 4-4.5
fat
BCS 5
severe over condition
study BCS images
x
desired and reasonable BCS for dairy cows at calving
3.5; 3-4
cows at peak milk
2; 1.5-2
mid lactation
2.5; 2-2.5
dry off
3.5; 3-3.5
heifers at 6 months
2.5; 2-3
heifers at breeding
2.5; 2-3
heifers at calving
3.5; 3-4
Phase 1 nutritional goals to achieve during early lactation
maximize intake (for every pound of DMI, milk production will increase by 2.5 lb)
minimize body tissue loss
one lb of body tissue mobilized during early lactation will supply
energy for 7 lb of milk
protein for 3.5 lb of milk
feeding recommendations for phase 1
high quality forage
palatable feed with high energy density
adequae effective fiber levels (min 20% ADF)
consider adding fat
use all natural protein supplements (no urea, NPN)
consider high quality bypass protien sources (UIP)
the _____ of protein in UIP fed to riminants is important
quality
what are the goals of phase II
maintain high milk production
beginto regain body condition lost during early lactation
phase II feeding recommendations
use palatable feeds with high energy density
use high quality forages
ensure adequate fiber levels
use all naterual protein supplements
phase III goals
restore BCS
limit overconditioning
target BCS at dry off: 3.25 to 3.5
phase III feeding recommendations
use lower costs feeds when possible and meet needs
consider use of NPN to meet a portion of protein needs
why feed dairy cow to replace body fat during late lactation>
????
phase IV goals
optimize fetal growth
prepare cow for next lactaion
minimize length of dry period (60 days)
achieve BCS of 3.5 at calving
phase IV recommendations
separate dry cows from lactating
avoid high grain diets to prevent abomasal displacement
avoid feeding excessive Ca levels to prevent milk fever
phase v goals
acclimate the rumen microbes to the diet that will be fed during early lactation
allows cows to be rapidly switched to a high grain diet with minimal digestive upsets
phase V feeding recommendations
feed .5 to 1.0 % of BW as grain to prevent acidosis
continue to limit intake of Ca to prevent milk fever
feed high levels of vitamein a and e to prevent mastitis
high producing cows are forced to make major ____ at calving
metabolic adjustments
tremendous nutrient demand shifts occur at
calving as cows redirect nutrient utilization to support high levels of milk production
cows have remarkable ability to _____ in an attempt to maintain homeostasis
mobilize body tissues (lipid, Ca, protein)
ability to consume feed lags behind the demand for nutirients during
first 8-10 weeks of lactation
during this period, cows are susceptible to
nutritional disorders
nutritional disorders in early lactating dairy cows include
milk fever ketosis retianed placentas or metritis fat cow syndrome displaced abomasum mastitis
incidence of clinical milk fever
8-9%
more prevalent in
high producing cows, and in cows with previous milk fever history
80% of cases occur within ____ of calving
48 hours
rarely occurs in cows during
1st lactation
what are the symptoms of milk fever
hypocalcemia (
typical Ca levels in nonlactating cows is
9.4
typical Ca levels in fresh cows is
7.7
milk fever cows are more susceptible to
mastitis, ketosis, dystocia, displaced abomasum, uterine prolapse
an 1100 lb dairy cow requires ____ Ca per day
30-40g during dry period
feeding ____ during dry period increases incidence of milk fever
more than 100 g (mechanisms to absorb Ca from GIT an dmobilize Ca reserves from bone are down regulated)
preventing milk fever in dairy cows; traditional method
feed low Ca (
preventing milk fever newer method
feed negative dietary cation-anion balance (DCAB) diets during dry period
DCAB
sum of positively charged ions (cations) and negatively charged ions (anions)
a ____ DCAB before calving will activate mechanisms to absorb more Ca from gut and moblize more a from bone
negative
recommended DCAB is
-10 to -15 meq/100 g diet DM
to accomplish this,
avoid high K level forages
add sulfate salts until S is maximized at 0.4 to 0.5% in diet
add chloride salts until DCAB is lowered to -10 to -15
challenges to feeding negative DCAB diets
anion salts are more expensive
high levels of anion salts are unpalatable (decrease DMI)
incidence of ketosis cases
2-15 %
aboute ____ of cows exhibit borderline ketosis
50%
most cases occur within ___ of calving
60 days
symptoms of ketosis
elevated ketone bodies
normal levels of ketone bodies
depressed blood glucose levels
distinctive acetone-like odor of the breath and fresh milk
appetite decrease; milk production decreases
cows develop ketosis gradually
cows seldom die from it
prevention of ketosis
avoid excess BCS at calving good transitiondiet in Phase V maximize DMI during Phase I feed oral glucose precuroses feed niacin for 2 weeks precalving and first 2-3 months of lactaton
