Aid to Selection Unsuitable for Sex-Limited and Carcass Traits

Correct Answer: Individual Selection

From the notes: Individual selection CANNOT be used for:

• Sex-limited traits: Sires cannot express milk yield, egg production — no individual record possible for these traits in the selected sex
• Traits with low heritability: Phenotype is a poor predictor of genotype when h² is low (large environmental component)
• Carcass/slaughter traits: Animal must be killed to measure carcass weight, fat depth, dressing % — the measured animal can no longer be selected for breeding

Solution for Each Limitation

• Sex-limited traits → Progeny testing (best)
• Low h² traits → Progeny testing / Family selection
• Carcass traits → Sib selection (slaughter sibling, select the individual)