Table 1 Summary statistics for egg production, body mass, and bone traits for the White leghorn a and b hens at 63 and 53 weeks of age, respectively, and Rhode Island Red hens at 68 weeks of age
From: No evidence that selection for egg production persistency causes loss of bone quality in laying hens
Trait | Number of individuals | Mean ± sem |
|---|---|---|
White Leghorn population a | ||
Cull body mass (g) | 933 | 1620 ± 5 |
Tibia breaking strain (N) | 933 | 207.9 ± 1.6 |
Total egg number | 933 | 240.8 ± 0.4 |
White Leghorn population b | ||
Cull body mass (g) | 969 | 1645 ± 4 |
Early egg number | 972 | 24.33 ± 0.20 |
Late egg number | 972 | 151.8 ± 0.2 |
Average egg mass (g) | 972 | 58.5 ± 0.1 |
Egg breaking strain 45 weeks (N) | 972 | 42.5 ± 0.2 |
Humerus breaking strain (N) | 958 | 178.1 ± 1.0 |
Humerus density (mm Al equivalent) | 955 | 1.092 ± 0.003 |
Keel density (mm Al equivalent) | 958 | 0.623 ± 0.003 |
Tibia breaking strain (N) | 969 | 215.6 ± 1.3 |
Tibia density (mm Al equivalent) | 970 | 2.056 ± 0.005 |
Rhode Island Red population | ||
Cull body mass (g) | 918 | 1907 ± 6 |
Early egg number | 925 | 29.9 ± 0.3 |
Average egg mass (g) | 972 | 63.3 ± 0.1 |
Egg breaking strain 45 weeks (N) | 972 | 54.2 ± 0.3 |
Late egg number | 925 | 245.1 ± 0.43 |
Humerus breaking strain (N) | 885 | 160.8 ± 1.7 |
Humerus density (mm Al equivalent) | 886 | 1.50 ± 0.01 |
Keel density (mm Al equivalent) | 884 | 0.829 ± 0.003 |
Tibia breaking strain (N) | 916 | 230.4 ± 1.8 |
Tibia density (mm Al equivalent) | 916 | 2.370 ± 0.009 |