B11: Breeding goal and characteristics (valuable traits) of beef and dual purpose cattle

Question 1

Breeding goal cycle: To start the process what do we want to breed?

Answer 1

Breeding goal —> valuable trait —> BVE ——————-> selection —> mating —-> production of offspring ———> Breeding goal again.

Question 2

What is the breeding value (BVi) of an animal?

Answer 2

The breeding value of an animal is the deviation of the genetic merit of the individual to the mean genetic merit of the reference population.

BVi = GMi - GMpop

Question 3

What are the most important traits of beef cattle?

Answer 3

-> repro performance
-> growth and gain performance
-> carcass merit

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

Question 4

What are the important factors of the repro performance trait of beef cattle?

Answer 4

• Conception rate:
  o Calf crop percentage (calves born)
  o Calf crop percentage (calves weaned)
• Calving interval (time elapsed between each calving)
• Birth weight related to calving difficulty
  o Calving difficulty scores:
  1) No difficulty, no assistance required e.g. angus
  2) Minor difficulty, some assistance
  3) Major difficulty, mechanical assistance
  4) C-section or other surgery (prolapse etc.) e.g. belgian blue
  5) Abnormal presentation: paralysis, iron in blood decreases.
• Maternal/nursing abilities
• Fertility testing of bulls
• Bull performance:
  o Average daily weight gain
  o Scrotal circumference (proportional to fertility)

Question 5

What are the important factors of the growth and gain performance trait of beef cattle?

Answer 5

• Birth weight
• Weaning weights (adjusted to 205 days)
• Yearling (365 days) & long yearlings (452/550)
• Post weaning rate of gain (min 140 days on test)
• Average daily weight gain
• Actual weight = Birth weight/age in days x 205 days + birth weight

Question 6

What are the important factors of the carcass merit trait of beef cattle?

Answer 6

carcass merit: the endpoint value of food animals depends on this.

Merit of beef carcass is based on:
* Dressing percent
* Carcass weight
* Carcass quality
* Fat ratio
* Ribeye area
* Marbling & tenderness