Table 2.
Estimates of the fixed effects in the statistical model, i.e., of time trend, season and parent stock age, per parameter on broiler flock level. † significant effect (P < 0.05 at least); # trend (P < 0.10); where no superscript is provided no significant effect or trend was found. β1–5 Refers to the respective terms in the statistical model, see materials and methods section and footnotes under the table.
| β1.1 Time trend (Linear) | β1.2 Time trend (Quadratic) | β1.3 Time trend (Cubic)1 | β2 Season (Sinus)2 | β3 Season (Cosinus)3 | β4 Parent stock age (Linear) | β5 Parent stock age (Loglineair) | |
|---|---|---|---|---|---|---|---|
| Average daily growth | −5.68* 10−4† | 1.81* 10−6† | 3 | 0.03 | 0.20# | −0.04 | 2.25† |
| Slaughter weight | −2.23* 10−4† | 4.41* 10−7† | −1.35* 10−10† | 5.27* 10−3 | 0.01# | −7.13* 10−4 | 6.46† |
| Carcass condemnation % | 5.42* 10−6† | 3 | 3 | 1.81* 10−3† | 4.61* 10−3† | 6.21* 10−5 | −4.82* 10−4 |
| Carcass weight uniformity %4 | −1.86* 10−5,† | 3.67* 10−8 | −1.51* 10−11† | 7.07* 10−4 | 1.46* 10−3† | −1.21* 10−4 | 1.73* 10−3 |
| First week mortality % | 6.84* 10−5,# | 3 | 3 | 0.01 | 0.07† | 8.83* 10−3† | −0.233† |
| Total mortality % | 1.04* 10−4† | 3 | 3 | 0.04† | 0.05† | 5.02* 10−3 | −0.10 |
| Antibiotics usage (addd/y)5 | −4.61* 10−4† | 3 | 3 | 0.02 | −0.01 | −3.56* 10−3 | −0.02 |
The seasonal sinus wave represents the spring-autumn variation (1st of March vs. 1st of September).
The seasonal cosinus wave represents the summer–winter variation (1st of January vs. 1st of June).
Non-significant quadratic and cubic time effects have not been fitted in the final model.
Uniformity: % carcasses with a griller weight lower than 65% of the average griller weight of a broiler flock, i.e., a higher percentage meaning a less uniform flock.
addd/y: animals defined daily dosages per year (Bos et al., 2013).