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Exam 2 Flashcards
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, carbs and sugars broken down to acetic and lactic acids, pH decreases until bacterial growth is stopped (4) |
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 - 4th: late gestation= rapid fetal growth (C) 3 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 |