Beef 2 Flashcards
***emphasized in class**** Covers finishing phase onwards.
finishing phase diets are high or low energy? composed of what?
high energy: lots of grain, small amounts forage, by product feeds
high energy: lots of grain, small amounts forage, by product feeds
larger and more specialized
in the finishing phase, diets are formulated to do what 5 things
increase growth rate, feed efficiency, animal health, and carcass quality; decrease cost of gain or maximize profit
increase growth rate, feed efficiency, animal health, and carcass quality; decrease cost of gain or maximize profit
28-29% body fat
what are the 3 types of diets used in finishing phase
receiving ration, step-up phase, finishing diet
finial finishing diets will contain what % concentrate, CP, roughage, and urea
80-95% concentrate, 13.5% CP, 1% urea, 9-10% roughage
5 most common grains used in finishing phase
barley, what, corn, wet and dry distillers grains, and alternative byproducts
name at least 2 protein sources
distillers grains, canola meal, soybean meal, cottonseed meal, sunflower meal
what is goal feed efficiency for finishing phase
5.5 to 7 kg feed per 1 kg gain
what is goal ADG for finishing phase
1.2 - 2.0 kg/d
what material can be used to improve feed efficiency
ionophores
what happens when some cattle moved directly from weaning to finishing diets
can reduce finishing weights and reduce feed efficiency (earlier and more rapid fat deposition); small frame breeds may promote finishing weights that are too low; this works better on larger frame breeds
newly weaned calves going to finishing lots are subject to severe stress from shipping, handling, mixing and treatment entering the feedlot. what are some negative effects of this stress?
reduce appetite, poor immune response, increase morbidity and mortality
why are calves given freee-choice grass hay during first week of finishing phase
the free choice hay stimulates eating
sick calves have higher or lower DMI when started on feed
lower
if there a standard nutrition program across finishing phase feedlots
no, it depends on feedlot operator
what are important things to know about finishing phase receiving diet
this is the first edit fed to calves in feedlot. they need free choice hay in bunk to a forage: concentrate diet with between 50-70% forage. also need water close to hay
what are important things to know about finishing phase step-up diets
3-10 diets that gradually increase grain (concentrate) level over 21-28 days, begins around 30-40% concentrate and reaches 85-95% concentrate, and the protein and energy is increasing
what are 4 objectives of step up diets of the finishing phase
minimize digestive disturbances, allow rumen microbes to adjust to starch, allow rumen epithelium to increase papillae area, minimize feed intake fluctuations
what is alternative diet adaptation strategy
rather than preparing 3-10 different step up diets, instead only prepare lowest and highest concentrate diet and then mix as needed to achieve target forage:concentrate ratio
why is rumens introduced at half dose during finishing phase (step up phase)
it is not palatable
what are objectives of finishing phase feed bunk management
keep animals eating consistently, maximize performance, and minimize digestive disorders this is a really important daily task in cattle finishing.
all cattle in same finishing phase pen should have ____ to consume feed and have feed delivered ______
same opportunity, same time every day (to avoid GI upset)
what are 2 finishing phase feed options
ad libitum (this gives higher feed wastage) or slick bunk (most feedlots use this)
describe slick bunk feed management
feed not reduced, but is regulated; there is short absence of feed; associated with improved performance, reduced sorting of ingredients, less feed wastage
how often should cattle be fed? how much feed should be left prior to the next feeding?
2x a day (cattle like a consistent time, amount, and ingredients so any changes should be gradual), only crumbs left
steady intake of feed leads to what
sustained growth
what is bunk reading
determining amount of feed that needs to be put into each bunk
as food intake decreases over the course of the day (as bunk level depletes), what happens to rumen pH? what should you be careful of with rumen pH level?
decreases. shouldn’t be below 5.5 for more than a couple hours or else can get subacute acidosis (ie erratic consumption is bad)
maximizing the DMI of animals in finishing phase leads to what 3 economically-friendly things
increase animal performance, reduce dats to slaughter, decrease production costs
in what order do the growth rates of bone, muscle, and fat peak?
bones, muscle, then fat
what is the order of peak fat deposition
perirenal, intermuscular, subcutaneous, then intramuscular (ie marbling, the intramuscular fat, occurs last)
as the animal grows, what happens to DMI/day and the requirements for CP, Ca, P, and energy
DMI/day and energy requirement increases, but CP, Ca, and P requirement decreases
feeding a diet high in acetate will lead to increased growth of which fat type
subcutaneous fat
feeding a diet high in glucose (starch) will lead to increased growth of which fat type
intramuscular fat (which is good for beef)
at the same BW, larger frame animals will have ____ fat
lower
large and small frame animals can be finished with equal fatness but not at the same _____
body weight
what 5 factors lead to increased finished weight
sex, genetics, plane of nutrition, beta agonists, and implant program
what is compensatory growth and how is it applied in beef production
ability of animal to recuperate growth after underfeeding (grow faster than normal); common to feed restrict and then give supplemented feed to lower maintenance requirements, lower energy content of live weight gain, and higher DMI than in normal growing cattle
what are possible outcomes of compensatory growth
full compensation, partial compensation, or no compensation
what 4 factors affect compensatory gain
age of animal during feed restriction, severity of feed restriction (affects time in compensatory gain), duration of feed restriction (affects growth rate), feed quality post restriction
grain sources with a high rate of rumen starch digestion is associated with increased risk of what?
rumen acidosis
what is associated with greater risk of rumen acidosis, dry-rolled wheat or dry-rolled sorghum?
wheat (because the rate of rumen starch digestion is higher)
how is acid produced in the rumen from bacterial fermentation countered (removed, buffered, or otherwise neutralized)?
buffered by saliva and feed absorption, passage from rumen
what is formula for processing index, PI
PI = wt processed / wt whole x 100% (ie, the measured bulk density of processed grain / the measured bulk density of whole grain, expressed as a percentage)
what is the limitation of PI to assess grain processing
poor rolling can cause large and small particles, but the PI could be in the acceptable range (particle sizes average to what you would achieve with proper rolling)
why should processed barley and wheat contain less than 30% fines (particles below 0.85 mm sieve size)
prevent acidosis
what processing index do we aim for? what fecal starch concentration do we aim for?
70%; 5-7% (note that these are related factors, fecal starch measure gives indirect information on PI)
what is the effect of ionophores
effect gram positive bacteria by disruption toning gradient across bacterial membrane with consequent reduction in intracellular pH
compare the effect of Monensin vs Lasolocid on feed efficiency, ADG, and feed intake
both feed efficiency. Monensin maintains ADG and reduces intake. Lasolocid improves ADG and does not change feed intake
this feed additive is a beta adrenergic agonist (compounds similar to endogenous catecholamines and they bind to receptors on skeletal muscle) to increase skeletal muscle mass and increase protein synthesis; it is fed at end of feeding period
ractopamine
what are 2 effects of ractopamine (cell level)
increase skeletal muscle mass and protein synthesis (detail: increase skeletal muscle mass and/or cross-sectional area of individual muscles; increases protein synthesis and reduces protein degradation)
what are 3 benefits to production when using ractopamine
improve: live and carcass gain (7-20 lb), feed efficiency (DMI/ADG), carcass leanness, fabrication yield, steak yield (does not change feed intake significantly)
when are liver abscesses detected
at alsughter
how are liver abscesses scored
0 = no abscesses; A = 1-2 small unorganized or 2-4 well-organized, or abscess scars; A+ = 1 or more large or multiple small, active abscesses
pathogenesis of liver abscesses
feeding practices or inconsistent bunk management (eg. rapidly increasing dietary energy through high-grain feeding or low-roughage diets) –> acidosis and rumenitis —_ entry, growth, and establishment of pyogenic bacteria
what antibiotic can be given in feed to reduce liver abscesses, increase growth rate, increase feed efficiency, and increase (very slightly) dressing percentage
tylosin
are liver abscesses more prevalent in high or low grain diets? in high roughage or low roughage diets? in beef breeds or in Holsteins?
higher provalence with high grain diets (12-32% prevalence); low roughage; Holsteins
why do legumes lead to bloat
rapid degradation and fermentation of legume leads to excessive polysaccharides produced by fermenting bacteria
give 3 general ways to control bloat
management of plant (maturity, variety, mixed legume pastures), management of animal (adaptation to pasture, intelligent grazer), use of additives (most effective)
when alfalfa is mixed with 30% DM basis of _____ in mixed ration, bloat incidence is reduced by 98%
sainfoin
how do plants containing tannins help prevent bloat
complex with cytoplasmic proteins and prevent formation of stable foam
give 3 plant bloat risk factors
after fall frost, heavy morning dew, immediately after rain
give 4 ways of managing bloat risk at animal level
put cattle on pasture at a time they are less hungry, adapt to grazing alfalfa, avoid morning dew, yearlings are at higher risk
how does alfasure reduce bloat
surfactant - EPS coated air bubbles allow gas to escape from destabilized air bubble
describe grass tetany, include indicators used to measure
Mg deficiency of ruminants associated with grazing fast-growing cool-season grasses during spring; hypomagnesemia indictors are urine <20 mg Mg/L; blood plasma or serum <18 mg Mg/L is low, <15 is concerning, <10 will have dramatic signs of tetany (18-32 mg Mg/L is normal Mg level in plasma)
why might measuring normal Mg in blood not be conclusive of grass tetany absence
late stages of the condition release Mg into blood (rupture muscle fibres) so measuring Mg levels in blood may not be conclusive
give at least 5 clinical signs of grass tetany
nervousness, rapid respiration, aggressiveness, stiff high-stepping gait, bellowing, muscle tremors, convulsions, hypersensitive to stimuli like loud noises
who is grass tetany most prevalent it? what might it be triggered by?
in all classes of cattle and sheep, but most prevalence among older females in early lactation (high Mg requirement); triggered by stressor like cold weather
why does magnesium need to be supplied daily
excreted in urine and milk
give 2 agronomic practices to reduce risk of tetany
add legumes to pasture mixes; apply N and K fertilizers that are aligned with needs based on soil tests
you are concerned about your cattle developing grass tetany in your lush spring pasture. you measure the soil Mg concentration to be 2.5 g Mg/kg DM and the soil K/(Ca+Mg) ratio to be 2.0. should you be worried?
no; safe concentrations are >2.0 g Mg/kg DM and the soil K/(Ca+Mg) <2.2
what soil and herbage factors influence Mg concentration and availability
high soil K levels negatively affect Mg soil uptake by plants (major factor); low levels of available energy, Ca, and P in forages reduce absorption and retention of Mg; high levels of organic acids, fatty acids, and N in forages can reduce absorption and retention of Mg
how can nitrate poisoning be prevented at a herd management level
test feed for nitrate concentration, diet high nitrate feeds with low nitrate feeds, replace dry forage with silage, frequent feedings, gradual adaptation to questionable feed, application of N fertilizers only as needed
how is nitrate poisoning treated
methylene blue drench to turn methemoglobin back to hemoglobin (although by time it is caught animal often dead); give alternate source of forage and include concentrates in diet
give at least 4 clinical signs of nitrate poisoning
staggering, rapid pulse, frequent urination, laboured breathing, collapse, coma, death; at sub-lethal levels abortion in pregnant females
describe nitrate poisoning; include at what level of nitrate levels this would occur
nitrate (NO3-) accumulates in plain tissue because of excessive uptake of soil N when plant metabolism of N is slow or stopped; nitrate poisoning occurs when nitrate levels are 0.5-1.0% of DM intake
what climate and soil factors can promote nitrate poisoning, give at least 3
factors that slow plant growth: cool temperature, cloudy weather, drought, frost, other physiological stress; or, soils heavily fertilized with N
how does excess nitrate in the rumen cause chocolate brown coloured blood? describe pathogenesis of nitrate poisoning
normally, NO3- (nitrate) in rumen is converted to NO2- (nitrite) then NH4+ (ammonium) by bacteria. NH4+ is absorbed into blood and excreted in urine. with excess NO3-, bacteria can’t metabolize NO3- enough, so NO3- and NO2- accumulate. NO3- is not harmful to hemoglobin, but NO2- binds to hemoglobin in blood, forming methemoglobin (specifically, converts Fe II to Fe III). methemoglobin cannot release O2 to body tissues (this is bad) and is dark brown coloured
rate and degree of NO3- reduction in the rumen depends on
microflora present and amount of energy available
