Variance Component Estimation and Multitrait Genetic Evaluation for Type Traits of Dairy Goats

*American Dairy Goat Association, Spindale, NC 28160
Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350

ABSTRACT Covariance components for final score and 13 linear type traits of dairy goats were estimated by multitrait REML using canonical transformation with an animal model. Data were 10,932 type appraisals from 1988 through 1994 from herds with <=40 appraisals. Heritabilities were estimated as 0.27 for final score, 0.52 for stature, 0.29 for strength, 0.24 for dairyness, 0.38 for teat diameter, 0.21 for rear legs, 0.32 for rump angle, 0.27 for rump width, 0.25 for fore udder attachment, 0.25 for rear udder height, 0.19 for rear udder arch, 0.25 for udder depth, 0.33 for suspensory ligament, and 0.36 for teat placement. Genetic correlations of linear type traits and final score were positive except for dairyness (-0.15) and teat diameter (-0.10); the largest correlations with final score were 0.66 for fore udder attachment, 0.44 for rear udder arch, 0.36 for rump width, and 0.30 for strength. The largest positive correlation among linear traits was 0.63 for stature and rump width; the largest negative correlation was -0.51 for strength and dairyness. Multitrait evaluations were calculated with data from all herds. Correlations between PTA calculated with animal and sire models ranged from 0.44 to 0.70 for bucks that had a PTA with a reliability of >=30%.

Key Words: animal model, variance component estimation, dairy goat, type traits

1997 J. Dairy Sci. 80:594-600

© 1997, by the American Dairy Science Association. All rights reserved.