Swine Selection Flashcards
What are the 2 components of swine performance?
- genetic ability of the pig
- environment
What are examples of environment components?
nutrition, health, facilities, management practices, etc.
What is the formula for phenotype?
genetics + environment
What are examples of paternal breeds?
- hampshire
- duroc
- chester white
- poland china
- spot
- berkshire
- pietran
What are examples of maternal breeds?
- yorkshire
- large white
- landrace
- large black
- hereford
- meishan
What are Hampshire good for?
muscling and therefore great for sire stride in breeding
What are Hampshire not good for?
not strong in litter size and maternal
What are Duroc good for?
rugged, meaty, fast growing, good mothers but males used in crosses
What problems do Duroc have?
problems with fatness
What are Yorkshire popular on and in?
maternal side in crossbreeding programs
What are Yorkshire good for?
large litters and good mothers
What are Yorkshire not good for?
muscling
What are Large White good for?
(same as Yorkshire) large litters and good mothers
What are Chester White good for?
(similar characteristics as Duroc) rugged, meaty
How are Chester White different than Duroc?
more fat and slower growth
What are Chester White characterized by?
durable breed and preferred coat color
What are Landrace characterized by?
long bodied and prolific
What are Berkshire good for?
(similar to Durocs) fine grain meat and fatness
What are Pietrain good for?
heavily muscles
What gene do Pietrain carry?
the stress gene associated with high muscling but susceptible to PSE problems and stress susceptibility
What does stress susceptibility lead to?
increased Mortality
What is PSE?
Pale Soft Exudative (pork quality)
What is the goal of genetics program?
do not allow inferior genetics or the mating system to limit production efficiency
How can you meet the goal of genetics program?
- identify a better source if genetics is the limiting factor in obtaining maximum production performance
- use the correct mating system that maximizes performance
- make sure herd health is not limiting performance
Are genetics usually the limiting factor in obtaining maximum production performance?
no
How can you make sure herd health is not limiting performance?
- may require herd depopulation and repopulation with healthy superior genetics
- understand costs of this choice
- if relocating, update genetics and improve health
What are the genetic resources available?
- genetic supplier
- breeds or lines
- choice of individual animals within the population (breed or line) of choice
- mating systems
- selection at the Nucleus (GGP), Multiplier (GP), and Commercial (P) levels
How is genetic supplier a genetic resource
choice of suppliers
How are breeds or lines a genetic resource?
choose the lines that excel for the traits that are important in your markets
How is your choice of animal within the population of choice a genetic resource?
- choose the animals that meet your selection criteria
- selection differential
What is selection differential?
the average of those you select compared to the entire group of potential select animals
What does selection differential impact?
the rate of genetic progress
What does PIC stand for?
Pig improvement company
How is selection at the Nucleus, Multiplier, and Commercial levels a genetic resource?
-genetic improvement is a slow tedious process so this ensures that selection is for traits that are important in your market
How are mating systems a genetic resource?
- use a mating system that matches your management preference
- maximize heterosis
- make use of breed complementarity
What are traits selected for for swine?
- number born alive
- number weaned
- sow longevity
- 21 day litter weight
- days to 115 kg (250 lb)
- feed efficiency
- backfat thickness
What is number born alive?
the salable item produced by the sow
What is 21 day litter weight?
what a producers selling weaned pigs is selling (minimum weight required to obtain full value)
What is days to market weight?
how long the pig will stay in finishing facilities and feed efficiency (daily maintenance requirement)
What is backfat and loin muscle depth or area?
determines percentage lean in the carcass which is the salable product (meat) for consumption
What questions should you ask yourself for selection?
- What traits to include in your selection program?
- Is the trait measurable?
What is important to consider when wondering if the trait is measurable?
- can the traits be measured accurately and in a repeatable fashion
- does the trait have sufficient variation (specifically genetic variation to which selection can be practiced)
If there is no variation…
there can be no improvement in the trait
What does whether traits can be measured accurately and in a repeatable fashion influence?
heritability and the rate at which traits can be improved
What features are necessary for swine selection?
- equal opportunity
- systematic measurement of all animals
- environmental adjustments
- NSIF adjustment factors
- use of records
What does equal opportunity mean?
no animals receive preferential treatment
What does systematic measurement of all animals mean?
for example: measure backfat the same way, same location, at the same weight on every animal
What are examples of environmental adjustments?
parity, season of year, on test weight, etc
What is parity?
number of times an animal has given birth
What is a formula for heritability?
δ^2G / δ^2P + δ2 E = h^2
What are NSIF adjustment factors?
uhhhhh
What is the importance of using records?
use records to assist in making selection decisions
What does STAGES stand for?
Swine Testing And Genetic Evaluation System
What model does STAGES follow?
multi-trait animal model
What registry does SWINE include?
NSR-National Swine Registry
What breeds are registered under NSR?
- duroc
- hampshire
- landrace
- yorkshire
What data does NSR include?
F1 (Landrace x Yorkshire) data to make maternal data more accurate
What is daily done for STAGES?
daily across-herd EPDs on association computer
What is published semi-annually by STAGES?
across-herd summaries
What does STAGES do with variance?
breed specific variance components and adjustments
For postweaning data, when are pigs scanned?
at or near 250 pounds (about 115 kg)
How often do breeders scan for post weaning data?
every 3-4 weeks
What pigs is post weaning data collected from? (not breed)
boards, gilts, and barrows
What are the types of post weaning data?
weight, backfat, loin muscle area
Where and when is post weaning data sent?
to NSR office same day and then results returned to breeder next day
What are program components of STAGES?
- records of ancestry (pedigree)
- performance measurement program
- EBV estimation program
- public access to the genetic rankings
- indexes to combine traits that economically influence selection decisions
Where is litter data recorded?
farrowing house
What litter data is recorded?
- pedigree information (sire and dam)
- date farrowed
- number born alive
- number after transfer (number allowed to nurse)
- 21-day litter weight
Where is litter data sent?
NSR
What types of mating systems do swine use?
- purebreeding
- crossbreeding
When is purebreeding used in swine?
at the nucleus level and some level at multiplication
What are the types of purebreeding?
- inbreeding
- linebreeding
- outcrossing
When is crossbreeding used in swine?
at the multiplication level and at the commercial level
What are the types of crossbreeding?
- terminal systems
- rotational systems
- rotaterminal systems
What is crossbreeding system for swine dependent on?
- health of herd
- management level
- cost
- other
What is the system goal of crossbreeding?
maximize heterosis or hybrid vigor
Why do you want to maximize heterosis?
- free
- has effects on those traits that involve fitness that typically influence profitability the most
What are some traits heterosis effects?
- conception rates
- number born and number born alive
- longevity
What is longevity?
how long the sow remains in the breeding herd
What are conception rates?
does a sow become bred or not
What does measuring number born and number born alive do?
limits the number of pigs that will eventually be sold
Are any pig breeds perfect/ideal for all traits?
no
What does crossbreeding allow?
the opportunity to mix breeds to create a breed mix that is more ideal than any of the parent breeds would have been
Ideally, what would a crossbreeding plan do?
mix breeds that complement each other; the strong points of one breed may offset the weaker characteristics of another, resulting in more complete, problem free pigs
What detrimental traits are selected against?
- PSS (or it might be PSE im not sure)
- Paralyzed Hind Legs
- Atresia ani
What is atresia ani?
no anus and no rectum
How is atresia ani heritable?
heritable with low penetrance
What is PSE?
pale soft and exudative, a meat quality issue
What does stand for PSS?
Porcine stress syndrome
What does PSS cause?
PSE
What does the Redement Napole gene do?
creates “acid meat,” glycogen that is stores is converted into lactic acid which reduces the pH and affects the meat quality
What pork quality measurements are taken?
loin pH, color, marbling, firmness, and drip loss
How can fat and color be measured?
both chemically and subjectively using a subjective score
What are the two types of PSS genes?
- Redement Napole (RN)
- Halothane (HAL)
What types of allele is RN?
both dominant (RN-) and recessive (rn+)
How is RN inherited?
on one locus
What does RN- do?
reduces the ultimate pH of the muscle and reduces WHC (water holding capacity) and increases purge (esp in ham and loin)
What is HAL?
a mutation on chromosome 6 of the pig at nucleotide 1843
What does HAL do?
increases lean meat content but enhances PSE and PSS
What is PSS?
animal lacks the ability to adapt to stress
What is HAL inherited from?
a single locus
What types of HAL alleles are there?
N normal and n mutant
What are the 3 possibilities of HAL?
- NN normal
- Nn carrier
- nn mutant (stress positive)
How are the 3 genotypes of HAL identidied?
DNA probe (PCR test)
What percent of HAL carriers will produce inferior muscle quality?
30-50%
Is all poor pork quality due to HAL?
no, only about 20% of poor pork quality was negative for HAL
Would eliminating HAL help pork quality issues?
yes, drastically
What kind of meat does PSS result in?
watery, chewy, and undesirable carcasses
How does PSS affect reproduction?
reproduce at lower rates and often die before they get into the breeding herd
What does being PSS heterozygous mean?
don’t show signs but carry the potential for stress
What is the worst condition for PSS?
homozygous recessive for HAL and RN
What genotype of PSS will cause problems and how?
homozygous or heterozygous for it will cause problems either in transit or at packing
How should you look at stress genes in a herd?
as if they are strictly terminal
