Table 7.
Coefficient of variance of body temperature and egg quality parameters over a 4-wk, daily, cyclic heat stress treatment (data collected from 398 individual laying hens).1
| Time period | Body temperature | Haugh unit | Yolk weight | Albumen weight | Shell weight | Shell thickness |
|---|---|---|---|---|---|---|
| Pre-HS2 | 0.59 | 5.9 | 16.4 | 10.2 | 7.9 | 10.3 |
| Acute2 | 0.83 | 6.5 | 16.3 | 12.8 | 11.2 | 14.6 |
| Wk22 | 0.73 | 6.8 | 15.5 | 9.9 | 7.4 | 10.4 |
| Wk42 | 0.67 | 6.9 | 9.5 | 13.1 | 8.3 | 8.1 |
1
Calculated by dividing the standard deviation of data at each time point by corresponding averages and multiplying by 100.
2
Pre-HS: data collected for the 2-wk period before heat stress; acute: data collected within 4 to 6 h of first heat stress exposure; wk2: data collected from the first 2 wk of heat stress; wk4: data collected from weeks 2 through 4 of heat stress.