B12: Estimation of breeding value in beef cattle Flashcards
what is the breeding value of an animal?
the breeding value of an animal is the deviation of hte genetic merit of the individual form the genetic merit of the refoernece populaiton.
BVi = GMi - GMpop
What is the aggregated BV?
it is a complex type of breeding value established for more traits simultaneously which is achieved upon the basis of a linear combination of breeding goal declared valuable traits.
What is the genomial BVE?
a strategy for applying genome-wide seleciton in dairy cattle.
approx 80% accuracy.
can be calculated at birth.
Performance traits eeof beef cattle?
the most important performance traits of beef cattle…..
1) reproduction
2) growth rate and gain
3) conformation / soundness
4) carcass merit
5) maternal ability
6) longevity
7) feed efficiency
8) body measurements
What are the factors involved in the reproduction performance trait?
- Calving interval
- Fertility
- Calving ease
- Docility
What are the factors involved in the growth rate and gain performance trait?
- Birth weight
- Gain (birth to weaning)
- Weaning weight
- Post weaning growth
- Feedlot gain
- Pasture gain
- Final feedlot weight
- Final yearling pasture weight
- Feed efficiency (feed conversion)
What are the factors involved in the milk production performance trait?
- Udder structure: Conformation, Height, Mature size.
- Weaning score
- Yearling pasture & final feedlot score
- Weaning
- Shoulder height, creep fed, non-creep fed
- Hip height, creep fed, non-creep fed
What are the factors involved in the carcass merit
performance trait?
- Grade
- Dressing percentage
- Carcass quality
- Ribeye area per hundredweight
- Fat thickness per hundredweight
- Marbling tenderness
- Retail product, %
- Retail product, kg
What is the heritability of most traits?
Most traits are moderately to highly heritable → Progress can be made through sire selection.
What is the mean heritability estimate of carcass weight?
0.4 - 0.5 = moderately heritable.
Indicates that carcass weight would respond well to selection.
What is the mean heritability estimate of longissimus muscle area?
approx. 0.4.
Indicates that longissimus muscle is moderately heritable & genetic gain might be achieved
through selection
What is the mean heritability estimate of the marbling score?
0.4 - 0.5
One of the most genetically evaluated carcass trait
What is the mean heritability estimate of the kidney, pelvic, heart fat %?
0.4
What is the mean heritability estimate of the dressing %?
0.3
* Moderately heritable
* Less reliable (significant variability btw estimates)
What is the mean heritability estimate of the adjusted back fat thickness?
0.4 - 0.5
* Suggests that genetic progress to single trait selection would be possible if records were available.
