Designing a breeding program

Question 1

Essential factors to consider when designing a breeding program

Answer 1

Size of production base
○ Sales = turnover = income = funding of breeding programme
○ Small volumes can be produced directly from nucleus flock(s)
○ Larger volumes require a production pipeline with multiplication levels

Level of sophistication
○ Natural selection
○ Variation

Security (dont want it to be stolen)

Cost

Question 2

What are rates of progress driven by in breeding program of poultry

Answer 2

Heritability

Selection intensity

Question 3

Heritability of different characteristics

Answer 3

Low heritability
- Egg number
- Fertility
- Hatchability
- Shell quality
- Robustness

Moderate heritability
- Growth rate
- Feed conversion
- Efficiency
- Skeletal quality

High heritability
- Breast meat
- Yield
- Abdominal fatness
- Conformation

Question 4

Predicting progress of poultry breeding programs

Answer 4

Genetic performance responds to selection pressure

Predicting performance depends on both genotype AND environment

Phenotype = genetic performance x environment

Question 5

Breeding value prediction and selection of poultry

Answer 5

Selection index combining family information - pedigree information

BLUP - Best Linear Unbiased Prediction
○ Most efficient use of all data
○ Information utilised from all relatives
○ Computer intensive

Question 6

What % is the maximum selection pressure on simple program (one trait)

Answer 6

2.5%

Question 7

Genetic correlations in poultry

Answer 7

Traits cannot be selected in isolation

Many have an effect on another trait
○ Sometimes in a synergistic/positive way, increasing progress in both traits
○ Sometimes in an antagonistic/negative way, limiting or reducing progress in one or both traits

Question 8

What method of security is used in the breeding lines of commercial poultry

Answer 8

All commercial lines sold are the product of crossing 2 or more lines together

It is impossible to ‘untangle’ the crossed lines to make them again. Therefore they can’t be acquired’ by others

The phenomenon of heterosis can be exploited for some traits

Question 9

Genomics of poultry

Answer 9

• MAS - Marker Assisted Selection
  ○ Microsatellite markers
  ○ Genetic maps
  ○ QTLs
  ○ SNPs
  
  • Not transgenics
  • Improved accuracy
  • Difficult traits e.g. Disease resistance