Growth Rate Distribution and Potential Non-Linear Relationship between Body Weight and Walking Ability in Turkeys

Area of Science:

• Animal Science
• Genetics
• Poultry Science

Background:

• Walking ability (WA) is crucial for poultry welfare and productivity.
• Understanding the relationship between growth rate and WA is essential for selective breeding.
• Previous studies suggest a potential link, but the nature of this relationship requires further investigation.

Purpose of the Study:

• To investigate the non-linear relationship between growth rate and walking ability in male turkeys.
• To quantify the impact of different growth periods on walking ability.
• To estimate the heritability and genetic correlations related to growth and walking ability.

Main Methods:

• Phenotypic data on body weight and walking ability were collected from 276,059 male turkeys.
• Growth rates were calculated for three distinct age periods (0-12, 12-20, and 0-20 weeks).
• Birds were categorized into quartiles based on growth rate distribution, and walking ability scores were analyzed across these quartiles.

Main Results:

• A higher growth rate was associated with increased incidence of poor walking ability (score 1) and decreased incidence of good walking ability (scores 4-6).
• Heritability estimates for walking ability ranged from 0.18 to 0.26.
• High genetic correlations between adjacent growth rate quartiles decayed with increasing interval, indicating a complex genetic architecture.

Conclusions:

• The findings strongly suggest a non-linear relationship between growth rate and walking ability in turkeys.
• Selective breeding for rapid growth may compromise walking ability, necessitating a balanced approach.
• Other unmeasured factors likely influence the complex interplay between growth and mobility in turkeys.