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Final - Cow Nutrition
cow nutrition
41
Agriculture
Undergraduate 4
04/15/2016

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Cards

Term
What are the classes of beef operations? (5)
Definition
Cow-Calf
Backgrounding/Stocker
Feedlot
Mature Cows
Replacement Heifers
Term
What do backgrounding/stocker producers do?
Definition
grow calf for 3-6 months post-weaning on pasture or dry lot
Term
What differentiates low-cost cow-calf producers from high ones?
Definition
feed management
Term
What factors characterize profitable cow-calf producers?
Definition
Control feed costs
-maximize pasture use, minimize need for supplements & feed

Superior genetics
-size, efficiency, milk production
-genetics that complement market desires & available resources

Diverse marketing strategies

Management based on facts & science not tradition and hype
Term
What are the typical objectives of beef cow producers?
Definition
-produce a 90%+ healthy calf crop at reasonable cost
-rebred by 80-85d postpartum to produce 1 calf a year
Term
What are some consequences of cow malnutrition?
Definition
-puberty
-postpartum estrus
-gametogenesis
-conception rates
-embryonic mortality
-prenatal development
-sexual behaviour
Term
What factors affect net calf crop?
Definition
Breeding Season
-restrict mating season so that calves arrive in narrow window, and feed is available for cows

Management of facilities to make work efficient

Records: cow temperament, maternal ability, milk production, calf size etc. to match to suitable bull

Herd health: disease control

Days open: nutrition, early weaning can affect

Calf survival: feeding affects perinatal losses, dystocia

Gestation: Nutrition, condition scoring

Bull fertility: nutrition matters
Term
What are the biological priorities for nutrients by beef cows (e.g if nutrition is lacking, what aspects will be 'hit' first)
Definition
1. Maintenance
2. Growth
3. Milk Production
4. Reproduction

repro will take first hit
Term
How old is a heifer at first conception? First calving? How long is gestation?
Definition
15 months

2 years

280d
Term
What age are calves weaned?
Definition
205d (7 mo)
Term
What is the target for first postpartum estrus?
Definition
want to conceive by 80d post partum
Term
Why is early onset of puberty important
Definition
will have had more estrus cycles before breeding, better conception rates

will produce more calves (as a herd)
Term
Are cows at mature body weight when they first breed? When they first calve?
Definition
no, 70% at first breeding, 80% at first calving
Term
What happens if a cow is too thin? Too fat?
Definition
-limited milk production, reduced conception rates

-too fat = excess lipid in mammary gland = less milk produced
Term
When is peak lactation?
Definition
60-80 days
Term
What is the most crucial time of year for beef production & reproduction? Why?
Definition
post-calving period (up to 80-85 days)

-peak lactation
-need to re-breed
Term
Do you need grains during post-calving period?
Definition
not necessarily, can have good forage to meet reqs. If trying to put weight on then maybe
Term
What drives nutrient demands when cows are pregnant and lactation?

What is the typical diet fed?
Definition
lactation

-good quality pastures if available
-otherwise good quality hay & silage
-no grain, minimal prot supps required as long as forages are good
Term
Mid-gestation is the best time for....
Definition
put weight and condition on thin cows
Term
How can cow/calf operations decrease winter feeding costs?
Definition
straw/corn stalks to use good qual hay for calves, sale etc

limit-feed concentrate based diets or high quality forage

maximize use of pastures/grazing (stock-pile grazing good idea)

minimize supplementation (cost of labour and the supplement)

control feed wastage

strategic use of expensive nutrients only when needed
Term
What is limit-feeding?
Definition
ASK SAM HELP
Term
What should be considered when planning winter feeding programs?
Definition
-estimate hay requirements
-assess quality of feed available
-cost of purchased feed vs what you can produce
-body condition of cows, separate into groups if practical
-temperature effects
Term
What are things to consider if grazing cows on corn residue?
Definition
-quality decrease as the residue weathers
-nutrient requirements as you approach calving
-snow cover, wet weather (limits intake)
-adaptation to grain (maybe) hard to predict what grain intake will be on corn residue
Term
What is swath grazing?
Definition
allow cattle to graze on swaths in winter that were swathed in the fall. environment affects quality big time
Term
What is flushing?
Definition
providing high quality feed prior to breeding season to maximize reproductive performance
Term
What are the 'staples' of cow nutrition? (4)
Definition
pasture
conserved forages
crop residues
byproducts

NO GRAIN

-match forage quality to animal demands
Term
What are the advantages of spring calving?
Definition
-means that nutrient requirements in winter are minimal (when harvested forages are fed)
-will be on highest qual pasture at time of highest requirements
Term
What are the advantages of summer & fall calving? con?
Definition
-can calve on pasture easily (cheaper, and healthier)
-will be market weight at a time when supply is lower (spring-calving is more common, most would have sold already)
-can put on high-qual pastures shortly after weaning

CON
-need to feed higher quality feeds through fall and winter to meet demands of lactation
Term
What requirement should be satisfied first when feeding cows, protein or energy?
Definition
energy

-if lacking, will use protein for energy which is expensive to supplement
Term
Why do you want to avoid over-feeding protein?
Definition
expensive ingredient

storing excess AAs as glucose is inefficient
Term
How can energy reserves in cows be assessed?
Definition
Use a scale to measure BW change (not always practical)

Visual assessment of BCS (not always accurate)
Term
What effect does poor BCS have on postpartum anestrus?
Definition
extends it
Term
Which is the best strategy, to meet requirements & maintain good BCS throughout the year, or to have cyclic losses and gains?
Definition
economically, cyclic losses and gains if you know how to make use of compensatory gain and providing good nutrition at critical times
Term
most important factor influencing reproductive performance
Definition
BCS at calving
Term
How might you separate cows into groups?
Definition
based on BCS
1-4 need higher qual feed
5-7 average feed
8-9 lower qual feed

Based on stage
-replacement heifers
-first calf heifers & older thin heifers
-mature cows in good condition
Term
How does bite size relate to cow nutrition?
Definition
first calf heifers (24 months old) will have immature teeth, wont have the same ability to take in feed that mature cows do. older cows may have lost teeth, same issue
Term
Why are fatty acids important for fertility?
Definition
precursors for steroid hormones
energy source
Term
Why is UIP important for fertility?
Definition
gluconeogenesis
hormones
Term
What are the effects of undernutrition in growing bulls?
Definition
-reduced growth
-delayed puberty
-lower testicular weight
-potentially permanently reduced sperm production
-reduced sperm viability
Term
What are the effects of overnutrition in growing bulls?
Definition
reduced long term performance
-fat deposition in sex glands
-joint issues
Term
Effects of undernutrition for the mature bull
Definition
reduced libido
impaired endocrine testicular function
impaired spermatogenesis & semen quality
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