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Final: Heifer Development
heifers
63
Agriculture
Undergraduate 4
04/15/2016

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Term
What is creep feeding? How do you do this when calves are with cows?
Definition
feeding calve separate ration from their dams
use feeder space that only calves can fit in
Term
What is creep feed?
Definition
palatable, easily digestible grains & protein supplements for an immature GIT
Term
What are the pros of creep feeding (3)
Definition
-teach calves to consume dry feed
-increase weight gain
-less strain on mother if pasture qual is low, and can maybe wean earlier
Term
What are the cons of creep feeding (4)
Definition
-low feed conversion
-non creep fed calves will compensate post weaning anyways
-heavier calves may actually bring lower prices (ppl think they dont have as much untapped potential)
-possible excess nutrition for replacement heifers
Term
Which age group of cows will benefit the most from early weaning?
Definition
1st calf heifers, because lactation is a greater nutritional stress for them than older cows who aren't simultaneously trying to grow
Term
What are the pros of early weaning? (3)
Definition
-improved BCS for cows if there is poor/limited forage
-increase weight gain of calves if kept & fed harvested/purchased feeds
-improve quality grade after finishing (maybe)
Term
What are the cons of early weaning? (3)
Definition
-greater initial costs (feed, labour)
-decreased cash flow if calves are sold at weaning
-increased health problems (maybe, possibly less developed immune system)
Term
What percentage of a cow herd is replaced annually?
Definition
16-18%
Term
Stages of heifer development
Definition
• Preweaning
• Weaning to Breeding
• Breeding to Calving
• Calving to Rebreeding
Term
What effects do preweaning implants have on reproduction?
Definition
impairs fertility
Term
What are the main considerations of preweaning management?
Definition
-good cow nutrition
-creep feeding or early weaning (if cow nutrition is limited)
-implants
Term
What are the main considerations of cow management between weaning time until breeding?
Definition
-fed separately from rest of herd

-nutrition should aim for higher number of etrus cycles before breeding (reach puberty at 12-14mo)

-want to be 65% of MW at start of breeding season

-breed heifers 3-4wks before cow herd

-manage for a short breeding season (45d)
Term
What are the main considerations of cow management between breeding & calving?
Definition
-calve at 85% MW
-last 50-60d before calving is critical
-feed heifers separately from mature cows
Term
What are the main considerations of cow management between calving & rebreeding?
Definition
-highest nutrient requirements
-may need to supplement if pasture/forage inadequate
Term
Poor Heifer Nutrition Results in:
Definition
• Increased age at puberty
• Lower conception rates
• Increased calving difficulty
• Increased calf morbidity and mortality
• Later born calves
• Lighter weaning weights
• Decreased % rebreeding of first calf
heifers
• Later rebreeding of first calf heifers
• Reduced lifetime productivity
Term
Why does spring calving cows lead to producing more lbs of calves when weaned?
Definition
better forage quality in spring
Term
Why do we see some cattle with very thick backfat?-
Definition
-producers sometimes feed to heavier weights to justify the cost of the cattle
-try to attain premium for more marbling (often doesn't outweigh the cost of feeding, or doesn't even result in marbling)
Term
When do cattle enter feedlots
Definition
Short
-fed over winter on forage diet, enter feedlot 11-13mo

Long
-fed over winter, grazed over summer, feedlot at 16-18mo
Term
How long do cattle stay on the feedlot?
Definition
3-6 months

-dont want to be more than 30 months old, otherwise will be considered mature and greater risk for mad cow disease
Term
What are the goals of a stocker/backgrounder?
Definition
develop animal frame and muscle NOT fat
train to consume grain

even out beef supply

provide low growth rate so can exhibit compensatory gain during finishing
Term
3 types of backgrounding programs
Definition
Over winter, will go on spring pasture then feedlot in fall

Replacement heifers, stocker calves to go to spring feedlot, or pasture then feedlot in fall

Feedlot entry in spring

(in order of increasing plane of nutrition)
Term
Things You Need to Know before Designing Backgrounding Ration (5)
Definition
• Frame size of calves
• Feed availability
• Target sale weight
• Target marketing date
• Degree of fleshiness desired
Term
Important management considerations when receiving weaned calves
Definition
-supply good qual grass hay bc dont know how to eat grain and may be subject to acidosis if introduced quickly. silage = risk of bloat

-vaccination
-deworm
-dehorm
-castrate
-antibiotics
-coccidiostat
-implanting
-ionophores
-gender
Term
Why use implants?
Definition
-improve feed conversion efficiency
-increase ADG
-decrease cost of gain
Term
What stages of production are implants used?
Definition
suckling
stocker-grower
feedlot finishing
Term
What are anabolic implants?
Definition
pellets containing cholesterol/lactose carrier, with silicone core & hormone crystal in center

dissolve during exposure to body fluids, releasing anabolic compounds
Term
What is payout rate?
Definition
length of time that implants are releasing compound
Term
What do estrogenic compounds do? (4)
Give an example of one
Definition
-increase size of pituitary & number of cells = increased GHRH sensitivity
-increase GH secretion = increased body protein synthesis
-increase number of GH receptors in liver
-increase IGF-1 production (promotes growth in almost all tissues)

EG: ESTRADIOL 17 BETA
Term
What does GH do?
Definition
somatotropin

promotes bone & muscle growth in young animals
Term
Why might progesterone be incorporated into some implants?
Definition
it prolongs concentration of estradiol in the blood
Term
What do androgenic compounds do? Give 2 examples
Definition
TBA: binds to androgen & glucocorticoid receptors to block catabolic effects of cortisol

TP: anabolic effects, prolongs estradiol release

Trenbalone acetate
Testosterone propionate
Term
Which has stronger growth-promoting effects, estrogenic or androgenic compounds
Definition
androgenic
Term
How do implants work?
Definition
-enhance protein deposition (rate of gain)
-increase live weight to attain carcass fatness (larger loin with same amount of fat)
-increase bone growth
Term
Why is increased bone growth due to implants possibly a problem?
Definition
carcass grades look at bone ossification to guess age, older cattle get downgraded
Term
How would you recommend a producer strategically use implants?
Definition
1. estimate slaughter date
2. Set goals for performance & quality grade
3. Work backwards from date to determine when the terminal implant should be used
4. Select initial implants based on terminal implant program
Term
Are suckling implants worthwhile?
Definition
depends! if you have to pay someone to put them in, probably not. if you do it yourself, yes
Term
How do grazed growing cattle respond to implants?
Definition
-well if implants are used in combination

-limited improvement if on a low qual roughage
Term
Problems with the Implant Procedure
Definition
abscesses

expelled implants

embed in cartilage

may increase dark cutters, reduce quality grade
Term
Why are abscesses a problem with implants?
Definition
will reduce ADG and F:G, increase cost per unit gain bc body spending energy to fight infection
Term
What effect do implants have on meat quality? (4)
Definition
Marbling (E not a bad as A)
Masculinity (TBA > estrogenic)
Skeletal maturity
Dark cutting
Term
What are ionophores used for?
Definition
antibiotics
Term
Give an example of an ionophore
Definition
monensin (rumensin)
lasalocid sodium (bovatee)
Term
How do ionophores work? (4)
Definition
change microbial populations & what they do in the rumen

Inhibit H2 producers = less CH4, more prop/acet
Inhibit NH3 producers = more avail protein
Inhibit lactate producers = higher pH
Decrease feed intake = less dilution = better feed digestion
Term
Why would you want to raise pH using ionophores?
Definition
higher pH = happier fibrolytic bacteria
Term
Which have a more complex cell wall, gram- or gram+ ?
Definition
gram -
Term
Benefits of Ionophores for Finishing Cattle
Definition
Improve Feed efficiency
• Effect on ADG – no change or slight
increase
• Decrease DMI – most prominent with
monensin (approx 6.5% decrease)
• Protein sparing effect – decrease rate of protein hydrolysis in rumen (can digest in SI instead)
• “Coccidiostat”
• Decreases incidence of lactic acidosis, bloat
Term
Are ionophores used for forage-based diets? Are they beneficial?
Definition
not as much as with high concentrate diets

-do improve ADG and feed efficiency in growing cattle
-might improve feed efficiency in mature cattle
Term
What is a short yearling vs a long yearling?
Definition
if born in spring

short = weaned in fall, backgrounded in winter, feedlot in spring @ 12 mo

long = weaned in fall, backgrounded in winter, pasture in spring, feedlot in fall @ 16-18mo
Term
What produces better results, finishing long yearlings or short yearlings?
Definition
long yearlings are on forage longer, provides less energy. may finish at a greater weight than short yearlings but will also be older

short yearlings get high rates of gain sooner bc go on grain sooner.

whether to produce long or short depends on how much money you can get/kg HCW, and grain costs. if ROI for finished cattle is low atm, or grain costs are high, should keep them on pasture for longer
Term
Advantages of Feeding Calf Feds
Definition
• Shorter amount of time to market
• Improved feed efficiency for finishing
period
• Less change of ownership
Term
Advantages of Feeding Yearlings
Definition
• Less time in feedlot – (more lots per year)
• Less concentrate to purchase for feedlot
phase
• Can prevent premature fattening
– Small & medium framed calves
• Calves are prepared for feedlot
– Health (would shipping fever be a problem
with yearlings ?)
– Consuming feed
– Compensatory gain
• Higher ADG during finishing period
Term
Why does it take more feed to put on a unit of fat vs a unit of protein?
Definition
fat replaces water whereas muscle (protein) draws in water
Term
Does feed conversion efficiency increase or decrease over time?
Definition
decrease, takes more feed per unit gain as animal starts getting fatter
Term
How are cattle marketed?
Definition
Cow-calf: direct or sales
Stocker/backgrounder: direct o sales
Feedlot: auction, direct to packer, specialty products
Term
What is live vs rail sales to packers?
Definition
live = based on animal BW
rail = based on hot carcass weight
Term
What factors influence meat yield & quality grade?
Definition
Conformation
Sex
Maturity
Fat (colour/texture/cover)
Meat colour/texture/marbling
Term
Why is fat important for meat grade? (2)
Definition
marbling = juiciness but NOT tenderness
fat prevents cold shortening
Term
What is yield grade?
Definition
% of carcass that is red meat
Term
What is muscle score based on?
Definition
size of the rib eye
Term
Major determinant of quality grade in
North America
Definition
marbling
Term
Does marbling affect tenderness?
Definition
no
Term
Things to consider when deciding what type of cattle to
raise as a cow/calf producer, how long to retain them, etc
Definition
Current & future market

What feeders want (hide colour, carcass traits, growth potential)

How much feed you have on hand
Term
Things to consider when deciding what type (age class and breed) of cattle to feed, how long to feed them, etc
Definition
-age at slaughter
-carcass weight
-yield grade
-quality grade
-where to market cattle
-feed efficiency
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