Beef Selection Flashcards
What are the parts of beef infrastructure?
- purebred
- cow/calf
- stocker
- feedlot
- packer
- consumer
What are the goals of beef infrastructure?
all different
What is purebred infrastructurealso known as?
seedstock
What is purebred infrastructure?
backbone of beef industry, provide purebreds and from that we can make all crosses
What is cow/calf infrastructure?
produce 1 weaned calf per year
What is the number one trait of cow/calf infrastructure?
reproductive
What is stocker infrastructure?
buy calves and wean then and grow (raise) them up to the point before feedlot
What is feedlot infrastructure?
fed to increase marbling (intramuscular fat) and put on weight
What is packer infrastructure?
cattle are processed (slaughtered) and cut into different sections
What is consumer infrastructure?
people go to store and buy meat
In what ways do beef differ from dairy?
- producer goals and objectives
- different environment and level of available natural resources
- more traits of economic importance
- sources of available performance needs
- slower adaption to technology
How does the environment affect beef?
greatly affects beef performance
Do beef cattle make faster or slower progress than dairy?
slower
How do beef cattle compare to dairy in terms of vertical integration?
beef lack vertical integration
How are the majority of beef traits correlated compared to dairy?
majority of beef traits are negatively correlated
How do beef differ from dairy in terms of goals and objectived?
dairy is generally all geared towards milk production whereas beef traits are in all different directions
How do beef differ from dairy in terms of available performance records?
there is no centralized record keeping system
How are records kept of beef cattle?
- each major breed association has its own published sire summary
- each AI organization has own sire formats based on information from each breed association
What are problems with beef performance records?
- sire summaries don’t mean semen or bull is available
- BV’s calculated within breed only (cannot use sire summaries to compare breeds)
- genotype x environment interaction can dramatically alter performance
Why are beef slower to adapt to technology than dairy?
-mainly because of small herds and part time ranchers
is crossbreeding used in beef cattle?
high level of crossbreeding
What is across breed EPD adjustments most useful to?
commercial producers purchasing bulls for use in crossbreeding programs
What does across breed EPD emphasize?
- uniformity for rotational crossbreeding
- divergence for terminal crossbreeding
- divergence of birth weight EPDs for bulls to breed to first calf heifers
What does accuracy of across-breed EPS depend on?
accuracy of within-breed EPD for the bull
Are uniform calves desirable or undesirable?
desirable
What is important to remember for divergence of birth weight EPDs for bulls to breed to first calf heifers?
first calf heifers produce small calves, so if you breed with a sire that produces large calves dystocia will occur
What does it mean to make across breed EPD adjustments?
after generating EPD, they have to carry out adjustments based on the breed you are gonna be crossing
Beef breeds?
- Hereford
- Angus
- Shorthorn
- Brahman
- Brangus
- South Devon
- Salers
- Red Angus
- Beefmaster
- Limousin
Are deleterious recessive alleles selected for or against?
heavily selected against
How can deleterious recessive alleles be selected against?
genetic testing
What are some diseases caused by recessive deleterious alleles?
- Tibial Hemimelia
- Curly Calf Syndrome
What breed does Tibial Hemimelia affect?
shorthorn cattle
What is Tibial Hemimelia?
severe, lethal deformity in calves; rear legs with fused joints, large abdominal hernias, and skull deformity
What type of disease is Tibial Hemimelia?
autosomal recessive
Can an animal that has TH be sold at ASA sanctioned sales?
no, but it can be registered
What breed does Curly Calf Syndrome affect?
Angus
What bull is responsible for Curly Calf Syndrome?
GAR Precision 1680
What type of disease is Curly Calf Syndrome?
autosomal recessive
What is Curly Calf Syndrome?
curved spine, extended and contracted limbs, and tend to have a “thin” appearance
What is developmental duplication?
one of the latest genetic disorders, calves born with extra limbs
What can cause developmental duplication?
embryo environment
What is developmental duplication called?
Polymelia
What is the change of two heterozygote parents having offspring with dd?
25%
What is a complication with dd?
incomplete penetrance, an individual might be dd but not exhibit it
Does having dd have a high embryonic death rate?
yes
What else can genetic testing be used for?
identify other traits (hetero vs homo polled, homo vs hetero black, tenderness markers)
What is the tenderness marker?
calpain
What is the point of genetic testing for tenderness markers?
to be able to pick animals that will provide more tender meat
What are some good points about beef selection?
- many economic traits have high heritability and are not sex-limited
- many traits can be easily measured
- consolidation of packing industry
What are trait types that can be measured in both sexes?
carcass and growth
What are examples of growth traits?
- birth weight
- weaning weight
- yearling weight
- ADG
What are examples of carcass traits?
- fat thickness
- marbling score
- REA
What is meant by consolidation of packing industry?
- boxed beef
- desired animal carcass standardization
- future changes in industry should be more consistent
What are the keys to success from a genetic standpoint?
- recognition of value of performance records and EBV’s
- Recognition and identification of breeds that excel in certain characteristics
- Selection
- Adjusted Weaning Weights
- MPPA
What does recognition of value of performance records and EBVs include?
- learn what they mean
- learn how they are determined
What should you keep in mind for successful selection?
- avoid fads (short term outlook)
- determine herd objectives
- select breeds compatible to objectives and environment
- objective measures for selection
What is the purpose of adjusted weaning weights?
to account for variations in weight between animals weaned at one time
What are possible sources of variation within a herd?
- genetic (cow/calf)
- age of calf
- breed
- age of dam
- sex of calf
What do adjusted weaning weights eliminate?
some sources of variation
know formula for adjusted weaning weights
((actual weight - birth weight) / age in days)) x 205 + birth weight = ADJ 205 d
What does MPPA stand for?
most probable producing ability
What does MPPA account for?
cows with different number of records
What does MPPA have?
repeatability
What does MPPA estimate?
probability of repeated documented performance in the future
What does repeatability refer to?
expression of same trait at different times in the life of same individual
What is an example of a repeatable trait?
weaning weight
Is repeatability higher or lower than heritability?
always higher
Why is repeatability higher than heritability?
because it accounts for maternal influence of cow that can be documented by previous calf performance
As number of records increases, repeatability estimate…
increases since it is more known about the animal in question
In the MPPA formula, what is n?
number of records for each individual
In the MPPA formula, what is r?
repeatability estimate for one record
In MPPA formula, what is HA?
herd average
In MPPA formula, what is CA?
cow average
