beef cattle nutrition Flashcards
what is the most common reason producers consult food animal veterinarians
disease diagnosis or treatment disease prevention information on nutrition information on production management financial or production analysis
what weight are beef cattle considered to have a fully functioning rumen
4 cwt (400lbs) because we wean at 500-600 lbs; so rumen needs to be fully functional prior to that
what is the purpose of rumen bacteria
they are a major source of protein for the cow;
what is the benefit of secondary rumen contraction
moves gas for eructation
why is the ruminant important
their ability to convert on untillable land
how much does a baby calf weigh when born?
80lbs
preruminant calf % of rumen
25%
preruminant calf % of abomasum
60%
heifer at weaning % of rumen
80%
heifer at weaning % of abomasum
7%
what is in the rumen
bacteria smaller than fungi smaller than protozoa
rumen motility
mixing
movement to omasum
rumination
eructation
how does the rumen get established?
esophageal groove closed so bypasses rumen in young animals (can bypass in adult by using copper sulfate); if esophageal groove does not close in bab calves it can cause bloat by getting milk into rumen;
what can cause the esophageal groove to not close
vagal nerve being pinched by mediastinal lymph nodes which prevent innervation of GIT and thus groove does not close properly (pneumonia can cause enlarged mediastinal lymph nodes)
what is the size of the rumen
40-60 gallons
how much saliva is produced per day
100-190 liters per day
what does saliva contain
Na bicarbonate
how much gas is produced per day
30-50 Liters per day
bacteria classified on
their actions (bacteria>protozoa>fungi)
what is the function of primary contractions
mixing and stratification
how many primary contractions occur
2 primary contractions in 3 minutes
what are the layers of the contents of rumen
gases
todays hay
grain and yesterdays hay
what stimulates primary contractions
low tension stretch receptors in reticulum
cold
eating and chewing
what causes depression of primary contractions
systemic disease
lack of stimulators
failure of vagal pathway
increased inhibitors- pain, fever, distension, VFAs, endotoxins hypocalcemia
why does high VFA decrease primary contractions
if VFA high, dont need anymore so contractions are depressed
what is the function of secondary contractions
associated with eructation, increases with distension
if gas is pressuring, they will want to have
secondary contractions
what is primary bloat
something stuck in esophagus and animal cant eructate
what is rumination
cud chewing; regurgitation, remastication, resalivation, deglutition
rumination occurs ____ a day
8 hours a day;
rumination increases with
more fibrous roughage
if you feed at 6 pm
calves will be born in the morning
where are VFAs abosrbed
rumen
unfermented CHO are converted to sugars in the
abomasum and intestines
mehtane in rumen lost by
gasses; eructation
carbon dioxide in rumen
lost through eructation
what is taken in by tissues
VFAs and sugars
acetic acid
oxidized in throughout the body; lipid synthesis (butter fat: jersey cows used for cheese and ice cream)
proprionic acid
major substrate for gluconeogenesis; critical because small amount of glucose reaches small intestines
butyric acid
oxidized in many tissues for energy production
DIP
degradable intake protein
UIP
undegradable intake protein
microbial protien
x
metabolizable protein
urea, soybean, cotton seed meal
protein degraded in rumen becomes
ammonia
ammonia becomes
microbial protien or absorbed in blood
ammonia absorbed in blood becomes
into the liver to become urea
urea becomes
excreted in saliva or taken up into rumen or excreted in urine
microbial protein becomes
protein in abomasum and intestine
protein in abomasum and intestine becomes
undigestable or degraded into amino acids
amino acids becomes
absorbed into blood and taken to liver
amino acid in liver becomes
used for tissue metabolism or converted to urea
Urea and NPN sources in rumen become
ammonia in rumen
degradable intake protein –>
microbial protein
undegradable intake protein –>
bypass protein
metabolizable protein includes
UIP and microbial protein
what happens to the rumen in an anorexic cow
becomes alkalotic
why????
more sodium bicarbonate being produced from saliva than acid from food
how do you obtain a rumen fluid sample
rumenocentesis; from right side, low on right side; 18 gauge needle
nasogastric tube
physical characteristics of rumen
color, consistency, odor, sedimentation test
chemical test of rumen
pH and methylene blue
acidosis occurs when
ph reaches 5.5 or less;
normal rumen ph is
5.5 - 7
if eating grass instead of grain, ph is more
alkalotic
microscopic exam
qualitative: activity of protozoa
quantitative: numbers of protozoa
methylene blue reduction test
2-6 minutes is adequate bacteria are present
10+ minutes inadequate bacteria present
how many pounds of feed do they need to get 1 lb of gain
6 lbs
pasture can be
native or improved
can add
mineral supplement and water
what is rangeland
not improved
how long is the winter feeding program?
about four months
basic cattle feeding
hay or pasture plus supplement
advanced cattl efeeding
hay or pasture plus stockpiled hay; add rye grass
late fall to early winter feed
stockpiled hay
winter pastures
oats and rye
grass is back in
april 15th and cows can be put back on pasture
forage assessment
sampling of pasture and hay
nutreint analysis
want to sample from everything cows are eating including stockpiled hay from each pasture and pasture
???????
???????
what compoents on a forage analysis report signfies energy
TDN
WHAT IS ADF
Acid detergent fiber
digestibility of ADF
lignin, cellulose, silica, etc
hi adf
low digestibility
what is ndf
neutral detergent fiber
fiber component so effects
DMI
NDF increases with
maturity of the plant
increase NDF
decrease intake
???????
????????
BCS 1
skeleton
BCS 5
not thin/not fat; cant see ribs
BCS 9
obese
why should you BCS in a beef herd
to monitor nutrition program
identify causes of low fertility
calculate economic losses of thin cows
BCS 5 cows
90% pregnant
BCS 4 cows
75% production of BCS 5.5
BCS 3 cows
50% production of BCS 5.5 cows
thin cows vs good body condition cows
lower calf survival
lower weaning weights
lower pregnancy rates
first calf heifers should be
6.0 at calving
mature cows should be
5.0 at calving
what are the key times to BCS beef cows
onset of calving
onset of breeding
mid-summer
pregnancy exxams
protein status cowpattyology
piled high= a lot of fiber
diarrhea with white spots = acidosis
what is most important in beef cattle nutrition
protein
winter feeding is based on
protein needs
cows are protein deficient in the
winter tiem
what is the most costly portion of a nutrition program
protein
winter feeding program
basic forage nutrient content
estimate dry matter intake (2-2.5% body weight)
calculate amounts of nutrients supplied
compare to NRC nutrient requirments
determine deficiencies/excesses
design a supplement to correct deficiencies
determine feed intake by
actual consumption or estimates of daily DMI
actual consumption
weighing feedstuffs; observation of consumption
estimates of DMI based on
percentages of body weight
1.5-2 bales of hay is what you need to hold back for cattle for winter
x
what happens when protein is added?
12% of rumen is working perfectly; if too low, add protein and bacteria start working better
nrc nutrient requirment table
?
beef cow nutrient requirements is based on
period of reproductive cycle BCS age cow size milk production environment
two supplement levels are
late gestation
early lactation
late gestation is
increasing BCS (will decline after parturition so make sure it is high)
early lactation is
maintaining BCS
cattle groups
young, old, and thin
mature, good BCS
time of day to feed supplement
noon to early afternoon
after 6 pm
positive associative effects of protein supplementation
rumen microbes need adequate protein to function properly
digestibility of forage increases (2-6%) with protein supplemenation until dietary protein is 8%
DMI increases 20-40%
negative associative effects of energy supplementation
excess energy lowers rumen PH and impairs rumen microbes
forage digestibility and DMI decreases
occurs with energy supplementation over 0.4% of body weigh
~5 lbs of grain/breeders cubes per cow
what is the number one mistake producers make
feed corn and not fulfill protein supplement
