Two-way selection for daily gain and feed conversion in a composite rabbit population

Area of Science:

• Animal Genetics and Breeding
• Quantitative Genetics
• Livestock Production

Background:

• Efficient animal production relies on optimizing growth and feed utilization.
• Understanding the genetic basis of traits like average daily gain (ADG) and feed conversion (FC) is crucial for effective selection.
• Previous research has explored selection responses in various livestock, but specific genetic correlations in composite rabbit populations require further investigation.

Purpose of the Study:

• To investigate the genetic parameters and selection responses for postweaning average daily gain (ADG) and feed conversion (FC) in a composite rabbit population.
• To estimate heritabilities and the genetic correlation between ADG and FC.
• To evaluate the effectiveness of selection for ADG on both ADG and FC.

Main Methods:

• A two-way selection experiment was conducted over three generations in a composite rabbit population.
• Selection lines included high-feed conversion (HFC), low-feed conversion (LFC), high gain (HG), and low gain (LG).
• An animal model was used to estimate heritabilities, genetic correlations, and breeding values, accounting for common litter and fixed effects.

Main Results:

• Heritability estimates for ADG and FC were substantial (.48 and .29, respectively).
• A strong negative genetic correlation (-.82) was found between ADG and FC, indicating that selection for one trait impacts the other.
• Selection for ADG was effective, with significant positive regression for HG and negative for LG lines; selection for FC also showed effectiveness.

Conclusions:

• Selection for increased postweaning average daily gain (ADG) effectively improved feed conversion (FC) in rabbits.
• The strong negative genetic correlation suggests that simultaneous selection for both traits or selection for ADG alone can lead to improved overall feed efficiency.
• These findings provide valuable insights for genetic improvement programs aiming to enhance rabbit meat production efficiency.