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When energy density increases, what happens with intake?
increases
When body weight increases...
intake increases
When forage quality increases...
decreased fiber concentration, increased feed intake
When cold stress increases...
intake increases
When heat stress increases...
intake decreases
Which cow breed eats the most feed?
Holsteins
Antibiotics...
increases intake; enhance muscle development and feed efficiency
What are ionophores?
type of antibiotic that modify microbes in the rumen and increase microbial fermentation
Monensin/ Rumensin/ ionophores....
decreases intake, performance is the same or better
Processing what type of feed increases intake?
hay/ forage
High empty body fat...
decreases intake
What is RFI?
residual feed intake, measures variation in feed intake beyond that needed to support maintenance and growth requirements
What does a negative and positive RFI mean?
negative: eats less than expected positive: eats more than expected
Carbonaceous roughage (CR)
less protein, include straws, stalks, mature grasses,
Proteinaceous roughage (PR)
high protein, include legumes and immature grasses
Forbs
primarily broadleaf, nonwoody plants
Browse
woody plants (consumed by ruminants)
Silages
includes ensiled forages, carbonaceous: corn and grass silage proteinaceous: alfalfa silages, clover
Carbonaceous concentrates (CC)
< 35% NDF. high in energy content, <20% CP. Class includes: cereal grains (ex. corn, oats), sorghum (ex. milo), grain byproducts (bran, middlings), misc. feeds (ex. animal fat. bakery byproducts)
Proteinaceous concentrates (PC)
>35% NDF, fair to high energy, >20% CP. Oil seed protein feeds (ex. SBM, CSM, peanut meal), grain byproduct protein feeds (ex. brewer's dried grains, urea) , animal protein feeds (ex. blood meal,)
Mineral supplements
bone meal, calcium carbonate, limestone
Vitamin supplements
fish oil, wheat germ, vitamin A acetate, vitamin D3 acetate
General characteristics of forages
high fiber content, high calcium content, high nutrient content
General characteristics of grains
high energy content, high phosphorous content
What kind of forage is more digestible?
cool season plants are more digestible than warm
What are cool season grasses + perennials + CR
timothy, tall fescue, wheatgrass, Kentucky bluegrass, smooth bromegrass, orchardgrass, ryegrass, reed canarygrass
What are warm season grasses + perennials + CR
bahiagrass, bermudagrass, johnsongrass, big bluestem, indiangrass, switchgrass, side-oats gramma, buffalograss, lovegrass, elephantgrass, kleingrass, limpograss
What are cool season grasses + annuals+ CR
ryegrass, oats, barley, wheat, triticals
What are warm season grasses + annuals+ CR
forage sorghum, sudangrass, grain sorghum, crabgrass, pearl millet
What are some miscellaneous CR?
straws (crop residue after grain harvest; ex. oat/ wheat/ barley straw) and hulls (byproduct of oil extraction, ex. cottonseed/ oat/ peanut hulls)
What are cool season legumes+ perennials + PR
alfalfa, red clover, white clover, birdsfoot trefoil, alsike clover
What are cool season legumes+ annuals+ PR
arrowleaf clover, crimson clover, winter pea, vetch, subterranean clover
What are some examples of warm season legumes+ perennials+ PR
peanut, kudzu
What are some examples of warm season legumes+ annuals+ PR
cowpea, lespedeza, alyceclover
What happens if wet forage is not properly stored?
aerobic microbes grow, creating yeast, mold, and fungi
As moisture level at harvest increases...
field and harvest losses decrease, storage loss increases
What are the 2 types of animal groups separated by priority grazing?
high requirement animals: young or pregnant, <4 body condition score. lower requirement animals: older, >4 bcs
What % moisture should forage have?
a level low enough to inhibit plant and microbial enzymes (to 15%)
What are the 3 types of hay losses in the field?
metabolic (loss of sugar and starch due to initial respiration losses), weather (rainfall between cutting and baling will prolong plant respiration and leach soluble nutrients/ increase leaf shattering), mechanical (leaf shattering loss in the field)
How do you reduce hay losses in the field?
use mower conditioner to decrease drying time (breaks stem to dry faster than leaves), add preservatives to allow aerobic storage of hay at higher moisture content (ex. propionic acid), add drying agents at time of cutting (ex. potassium carbonate)
How do you reduce hay losses in storage?
store hay in barn or under a roof, use baler with plastic wrap attachment, cover bales with plastic tarp
What is silage?
product of controlled anerobic fermentation of green forage crops that have been compressed and stored in oxygen limiting containers called silos
What are the advantages of silage compared to hay?
preserves a higher proportion of plant nutrients, high quality feed with little waste, harvesting not as dependent on good weather, flexibility of harvesting crops
What are the disadvantages of silage compared to hay?
inflexibility in marketing (storing, handling, and hauling is expensive), reduces amount of organic matter returned to soil
What is the best and worst type of silo?
best- air tight upright, expensive worst- horizontal dirt trench, cheap
What are the acids produced during the ensilling process?
acetic (first one produced during anaerobic phase), lactic (most abundant), butyric (higher levels in bad silage), propionic and formic (little produced)
What are general considerations with silages?
optimal pH is 3.5-4.5, 25-35% dry matter is ideal for making good silage, well made silage will last 10-15 years, stage of maturity when harvesting is critical
Corn silage
most popular silage in the US, moderate to high energy, low in protein
What is the ranking of nutritional quality of forages by plant species?
(highest to lowest) legumes, cool season grasses, warm season grasses, annual grasses, perennial grasses
What is the relationship between plant maturity and forage quality and quantity?
maturity increases= quality decreases= quantity increases
What is the ranking from greatest to least negative effects on forage quality?
warm season grasses, cool season grasses, legumes
What are common traits of cereal grains?
high energy, low fiber content, moderate protein content but low quality, good source of phosphorous for ruminants, low calcium, should be processed before feeding (ground, cracked, steam flaked), low in vitamin A and D
How are cereals compared to forage?
cereal: high phosphorus, low calcium forage: high calcium, low phosphorous
What are common traits of oats?
considered a safe feed for horses due to high fiber content, 35% hulls by weight, suited for ruminants, limitted amount for swine diets because of high fiber, more fiber-> less energy-> less lactic acid
What are common traits of wheat?
higher feeding value than corn, energy equivalent to corn, best protein quality of all common cereals (but still poor in general), not widely used due to high cost, used primarily for human consumption
What is grain processing?
purpose: to increase digestibility of nutrients and improve feed efficiency; done by increasing surface area (and reducing particle size), heat and pressure gelatinizes starch granules and disrupts the protein matrix inside the cells of the endosperm
What are other names for grass tetany?
wheat pasture poisoning or hypomagnesemia
What are the symptoms of grass tetany?
staggering, twitching, falling down and unable to get up
What is grass tetany caused by?
low MG consumed/asborbed from forage causing low muscle MGglevels
What happens if grass tetany isn't treated?
the animal can die from muscle convulsions within a few hours of observed symptoms
What are factors that may inhibit Mg absorption?
low Ca and Mg levels in forage, high K levels in forage, high protein in forage, grazing fall and winter grain pastures which are undergoing periods of rapid growth
What animals are most at risk for grass tetany?
pregnant beef cows (last trimester), lactating beef cows (first 2 months of lactation), younger cows
What are some ways to prevent grass tetany?
apply limestone to acid/ sandy soil, graze older dry cows or stocker calves on suspect pastures, feed Mg oxide (not palatable and expensive; can mix in liquid feed, range cubes, or mineral blocks)
How is grass tetany treated?
inject Ca-Mg gluconate solution into the jugular vein to elevate blood Mg concentration
What are the symptoms of pulmonary emphysemia?
lungs expand but won't contract (gasping) and may rupture
What happens if pulmonary emphysemia isn't treated?
the cow dies from lack of oxygen, die quickly when they get excited
What is pulmonary emphysemia caused by?
rumen microbes convert tryptophan to 3-methylindole, grazing immature lush pastures up to 5-14 days of age or regrowth after cutting... takes time for reaction to set up (1-2 weeks after putting cows on pasture)
What animals are most at risk for pulmonary emphysemia?
cows (calves do not get it)
How is pulmonary emphysemia treated?
inject atrophine and antihistamine to improve lung function (antibiotics will help secondary infection)
What are some ways to prevent pulmonary emphysemia?
gradually remove cows from pasture (too fast and the cows will get excited), let pasture mature for 2 weeks before grazing again, put rumensin in the diet
What is another name for dallisgrass poisoning?
bermudagrass tremors
What are the symptoms of dallisgrass poisoning?
cow is hyperexcited, stumbles and falls when chased, lack of coordination and unusual stance... does not usually die
What is dallisgrass poisoning caused by?
ergot fungus on the seed head of mature dallisgrass, bermuda grass tremors caused by a fungus associated with tremorgenic mycotoxin (from tall grass)
How is dallisgrass poisoning treated?
supportive care with feed and water, gradually remove animal from pasture, use antibiotics for recovery
What are some ways to prevent dallisgrass poisoning?
shred mature dallisgrass to get seed heads off, keep bermudagrass grazed down and short, if severe; burn the field
What is nitrate toxicity caused by?
elevated nitrate levels in forage from drought, frost damage, herbicide treatment, or high nitrate in the soil... nitrate oxidizes hemoglobin to methemaglobin which cannot carry oxygen... poisoning can cross placental barrier
What are the symptoms of nitrate toxicity?
colic pain, diarrhea, tremors, staggering, cyanosis, abortion, chocolate brown blood... if untreated can cause death
What kind of animal does nitrate toxicity affect and why?
ruminants because nitrate can be converted/reduced to nitrite in the rumen (more toxic than nitrate)
How is nitrate toxicity treated?
methylene blue IV (administer very slowly)
What are some ways to prevent nitrate toxicity?
have nitrate levels in forage analyzed (0.0-1% safe to feed), feed fresh forage (nitrates are released quicker in dry forage), include starch in feed so that less nitrites are absorbed (ex. corn)
What is prussic acid poisoning caused by?
stressful events that cause plant cells to rupture (drought or frost), young new sorghum or sorghum in fresh regrowth stage
What kind of animal does prussic acid poisoning affect and why?
ruminants are more susceptible because the ruminal microbes have enzymes that release prussic acid
What are the symptoms of prussic acid poisoning?
excitement, hyperpnea, cyanosis, unconsciousness, suffocation, cherry red blood... animal can die within 2 minutes of grazing
What are some ways to prevent prussic acid poisoning?
do not graze new growth sorghum, if you do, turn cattle out into the pasture with a full rumen so they will not eat too much (small amounts consumed is okay)
How is prussic acid poisoning treated?
sodium nitrite followed by sodium thiosulfate
What is kleingrass poisoning caused by?
plant saponinsthat can't be removed by the liver fast enough, causing the liver to deteriorate
What kind of animal does kleingrass poisoning affect?
sheep, goats, and horses
What are the symptoms of kleingrass poisoning?
sunburn and the head will swell
What are some ways to prevent kleingrass poisoning?
remove sheep from pastures as soon as you see swelling of the head, put the sheep in the shade to prevent excessive photosynthesis... no known treatment
What are the symptoms of fescue grass toxicity?
poor performance (weight loss, no growth), heat intolerance, red bag syndrome in horses
What is fescue grass toxicity caused by?
alkaloids produced by an endophyte in fescue will cause dry rot or dry gangrene condition in the tips of ears, tail, and hoofs
What is another name for fescue grass toxicity?
summer slump
What are some ways to prevent fescue grass toxicity?
remove animal from pasture once signs are observed, graze fescue for 2 weeks and then another pasture for 2 weeks to give animals a chance to rid the body of alkaloids, no cure for gangrene damage already done
What factor is important when managing herd nutrition?
supplementing the diet because it's hard to determine intake
What is the typical size of a herd?
<100 head
Why is beef more profitable than pork if it costs more to produce?
more demand for beef, beef cow an utilize feed more efficiently beause it's a ruminant and can be fed low quality protein feeds
What is energy needed in a cow for?
maintenance, pregnancy, lactation, and growth (1st and 2nd calf cows)
How much energy is used by the cow for maintenance?
half
What are the factors affecting NE requirements?
body weight (equation: .077 x BW^.75), physiological status, activity, environment, breed or genetics
What is the ranking for cow breed maintenance?
dairy > bos taurus > bos indicus
What factors affect maintenance during pregnancy?
stage of gestation, number of fetuses, birth weight of calf
What factors affect maintenance during lactation?
stage of lactation, amount of milk produced
What happens if there is a lack of copper in the diet?
hair falls out
What are important macrominerals to supplement?
calcium, phosphorous, magnesium, sodium
What macromineral has the problem of being too high?
sulfur
What are important microminerals to supplement?
copper, zinc, selenium
What are manganese, cobalt, and iodine needed for?
manganese: reproduction cobalt: vitamin d synthesisiodine: thyroid function
What is the importance of micromineral nutrition on reproductive performance?
enhanced bull and cow fertility, enhanced immunity,
What is the importance of micromineral nutrition on producing healthy calves?
enhanced cold tolerance, colostrol antibody transfer, enhanced immunity
How do you supplement minerals?
free choice: salt meal, salt block, salt liquid feed
What are vitamin requirements for beef cows?
vitamin A,D,E (critical when green forages not available). does not need to supplement water soluble vitamins.
When are the critical stages in production?
calf is born and start of last trimester
What BCS is best for a cow at the time of calving?
5
What may happen if a cow with a BCS of less than 4 calves?
the calf may be weaker and slower to suckle,more susceptible to cold stress and pathogens
Why can't cows eat low quality forage?
because the fiber is increased, indigestibility is increased, protein and ammonia is decreased, which decreases intake and rate of passage
What ratio do rumen microbes require?
4:1
What is the relationship between DMI and TDN:CP?
inversely related
What is the threshold TDN: CP ratio?
6:1, if the ratio is greater than 6, it will have problems being digested
What is the substitution effect?
if there's too much supplement being offered, the animal will eat more of it than feed which increases the feed costs. a low level of supplement increases forage intake and overall nutrient intake.
What are corn and cereal grains good for?
supplementing low TDN:CP forages
What is cotton seed meal good for?
supplementing high TDN: CP ratio
What percent should you not supplement over?
5% of the animal's body weight
What is the replacement rate of heifers?
20%
What are the impacts of underdeveloping heifers?
delayed sexual maturity, reduced proportion of heifers bred early in the season, lower pregnancy rates, increased calving difficulties
What are the impacts of overdeveloping heifers?
increased production costs, reduced conception rate, impaired mammary gland development (too much fat in udder is permanent), decreased milk production and weaning rates
What are the impacts of supplementing ionophores?
growth rates and feed efficiency improve, heifers reach puberty earlier
What is creep feeding for?
to increase the milk production of the cow by weaning the calf early
When is creep feeding beneficial?
fall calving herd, dry lot cow operation, first calf heifers, when milk production is low, when calves are going straight to feedlot
What is the ensilling process?
aerobic stage: 02 consumed, C02 and water produced, energy released and heat produced, aerobic yeast and mold growth, pH decrease, last for several days anaerobic stage: (lasts 1-2 weeks) anaerobic bacteria grow, aerobic yeast and mold die, protein broken down to AA, NH3, and amides, car…
What are the critical and non critical stages of production for a cow herd?
- 1st: calving to breeding= early lactation, prepare cow for rebreeding, highest protein requirements (C) 3 months - 2nd: breeding to weaning= slow fetal growth, late lactation (NC) 4 months- 3rd: weaning to late gestation= slow fetal growth, lowest protein requirements (NC) 2 months - …
What method of harvesting alfalfa has the lowest percent of field loss?
green chop or direct cut silage
What micromineral is most likely to be deficient in cattle grazing grass in Texas?
copper, zinc
What is continuous grazing?
the animal has continued access to an area of land over a set time period
What is rotational grazing?
frequent periods of grazing and rest between two or more pastures; allows pasture plant rest and growth and a more stable supply of nutrients for the animal
What is first-last grazing?
animals with higher requirements (younger, pregnant, lactating, thinner) have first access to high quality forage in a new pasture while animals with lower requirements (older, fatter) go second
What is strip grazing?
utilizes a temporary electric fence to force the animal to feed on both the leaves and stems of the plant in plotted out areas
What is limit grazing?
animals are allowed access to certain paddocks for a short amount of time , 2 side by side paddocks with hi and lo quality forage
What is creep grazing?
gives animal access to high quality feed through creep feeders
What is body condition score used for?
to estimate body fat reserves in cow/ monitor energy status
What kind of hair coat has the lowest critical temperature?
winter hair coat (then fall, and summer is the highest)
What is the equation for the target growth rate for optimal development of heifers from weaning to breeding?
body weight at maturity- body weight at weaning / age at maturity - age at weaning
What attribute of microbial fermentation occurs in the rumen?
pH remains constant
What attribute of microbial fermentation occurs in the silo?
low amounts of propionic acid, high amounts of acetic acid
What attribute of microbial fermentation occurs in the rumen and silo?
cho => sugars => VFAs, protein hydrolyzed to AA=> NH3=> microbial protein
What type of forage has a higher digestibility/ energy?
cool season
If a warm season grass is harvested at a later stage, what happens to nutritional value?
it decreases
What is the ranking (from highest to lowest) of digestibility for types of forages?
legumes, cool season, warm season
What are the consequences of harvesting forage as hay with a moisture content of 20-25%?
when moisture is too high, metabolism continues and can lead to combustion and a barn fire
What factor is a cow's NEm requirement multiplied by if she is lactating/ a dairy breed or Simmental?
1.2
To adjust for cold stress, how much is the NEm requirement increased by per degree F below a cow's lower critical temp?
1.0%
What is the correct sequence of reactions that occur in the rumen of cattle fed forage with high nnitrates?
nitrate (NO3) => nitrite (NO2) => ammonia (NH3)
Hay harvested later has a __________ fiber concentration the hay harvested earlier.
higher
What factors increase protein requirements in beef cows?
body weight, stage of gestation, amount of milk produced
What is the causative agent of pulmonary emphysema?
3-methylindole
Replacement heifers should weigh ___% of their body weight at the start of breeding season
80-85
What trace/ micromineral is needed in late gestation to avoid impaired passive immunity transfer?
selenium
What forage toxicity problem affects cows and horses?
dallisgrass poisoning
What factor has the greatest affect on digestibility of hay?
stage of maturity before harvest
Which macromineral's elevated levels reduces the absorption of microminerals?
sulfur
What 2 factors affect lactation in beef cows?
temperature, amount of milk produced

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