Genotype by feed interaction for feed efficiency and growth performance traits in pigs

Area of Science:

• Animal Science
• Genetics
• Animal Nutrition

Background:

• Reducing pork production costs is crucial, with feed representing over 75% of expenses.
• Feed efficiency (FE) traits are a priority in pig breeding programs.
• Regional diet differences (corn-soybean vs. wheat-barley coproducts) create opportunities to study genotype by environment interactions.

Purpose of the Study:

• To investigate genotype by feed interaction (GxF) for FE and growth traits in pigs.
• To compare direct and indirect selection responses under different diets.
• To assess the impact of GxF on lipid deposition and residual intake traits.

Main Methods:

• Studied 3-way crossbred growing-finishing pigs fed either corn-soybean (CS) or wheat-barley (WB) diets.
• Analyzed GxF for growth, protein deposition, feed intake, energy intake, feed conversion rate, lipid deposition, residual energy intake (REI), and residual feed intake (RFI).
• Evaluated direct and correlated selection responses under both diets.

Main Results:

• GxF did not alter genotype rankings for growth, protein deposition, feed intake, energy intake, or feed conversion rate.
• GxF significantly impacted lipid deposition, REI, and RFI rankings and genetic variance.
• Selecting pigs on a different diet than the performance diet compromised lipid deposition and residual intake traits.

Conclusions:

• Pigs can be selected for growth and feed conversion on either CS or WB diets, enabling cost reduction by switching to WB diets.
• For lipid deposition and residual intake traits, selection must occur on the same diet as performance to avoid compromising results.
• Future breeding programs should consider selecting for FE on lower-input diets, anticipating their increased prevalence.