Table 1.
Coefficient of variation for BW (BW CV) at various ages of hens fed with a precision feeding station toward a High and Standard BW1 curve and photostimulated (PS) at wk 18 or 21.
| –––––––––––––––––––– BW CV (%) –––––––––––––––––––––– | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| BW | PS | Week 4 | Week 7 | Week 14 | Week 18 | Week 21 | Week 27 | Week 40 | Week 54 | Pooled SEM | |
| Wk2 | 5.7x | 2.4y,z | 0.3z | 0.4z | 0.9y,z | 2.8x-z | 3.5x,y | 3.7x,y | 1.0 | ||
| BW × wk | High | 7.9a | 2.1 | 0.3 | 0.4a | 0.9 | 4.4a | 5.4a | 6.0a | 1.1 | |
| Standard | 3.4b | 2.6 | 0.4 | 0.4a | 0.8 | 1.3b | 1.6b | 1.3b | |||
| PS × wk | 18 | 7.1 | 2.1 | 0.4 | 0.5 | 0.7 | 3.0 | 3.0 | 4.0 | 1.3 | |
| 21 | 4.2 | 2.7 | 0.3 | 0.3 | 1.0 | 2.7 | 4.0 | 3.3 | |||
| BW × PS × wk | High | 18 | 11.0a | 1.8 | 0.4 | 0.5 | 1.0 | 4.6 | 5.5a | 7.5a | 1.6 |
| 21 | 4.9b | 2.5 | 0.2 | 0.3 | 0.8 | 4.1 | 5.4a,b | 4.6a,b | |||
| Standard | 18 | 3.3b | 2.3 | 0.3 | 0.5 | 0.4 | 1.3 | 0.5b | 0.5b | ||
| 21 | 3.6b | 2.8 | 0.4 | 0.4 | 1.2 | 1.2 | 2.6a,b | 2.0b | |||
a,bLSMeans within a column and treatment group lacking a common superscript differ (P ≤ 0.05).
x–zLSMeans within a row lacking a common superscript differ (P ≤ 0.05).
1Hens followed either the breeder-recommended BW curve (Standard) or an accelerated BW curve reaching the 21 wk BW at 18 wk (High).
2 P-values for the different sources of variation were as follows: wk, P = 0.012; BW, P < 0.001; PS, P = 0.686; BW × PS, P = 0.044; week × BW, P = 0.014; week × PS P = 0.895; week × BW × PS, P = 0.448.