Method to Estimate Repeatability

Correct Answer: Intra-class Correlation

From the notes: Repeatability is estimated by intra-class correlation — the correlation between repeated measurements of the same trait on the same animal (e.g., first and second lactation milk yield).

Distinction

• Repeatability: Estimated by intra-class correlation (r) — repeated records of the same individual ✔
• Heritability (best method): Half-sib correlation — free from dominance and common environmental effects
• Heritability (least reliable): Full-sib correlation — confounded by dominance (VD) and common environment (VEC)
• Sire evaluation: BLUP — most recent and best method

MPPA Formula

MPPA = Population mean + nr/(1 + (n−1)r) × (mean of animal's records − population mean), where n = number of records and r = repeatability.