Table 2.
Univariable analysis of the relationship between the use of screened bottom boards and the winter colony loss rate.
| The Winter Colony Loss Rate (95% Confidence Interval, CI 95%): | Entire Study Population (n = 1035) | Beekeepers Using | Univariable Analysis a | Multivariable Analysis b | |||
|---|---|---|---|---|---|---|---|
| Screened Bottom Boards (n = 586) | Solid Bottom Boards (n = 449) | p-Value | Crude Odds Ratio (ORcrude) (CI 95%) |
p-Value | Adjusted Odds Ratio (ORadj) (CI 95%) |
||
| Overall | 12.1 (10.3–14.2) |
11.3 (9.5–13.3) |
13.0 (11.0–15.3) |
<0.001 | 0.851 (0.801–0.905) |
0.003 | 0.905 (0.847–0.967) |
| Due to: | |||||||
| Natural disaster | 0.4 (0.3–0.5) |
0.4 (0.3–0.6) |
0.4 (0.3–0.6) |
0.538 | 1.104 (0.806–1.513) |
- | |
| Management-related factors | 11.7 (9.9–13.8) |
10.8 (9.1–12.8) |
12.6 (10.6–14.9) |
<0.001 | 0.844 (0.793–0.898) |
0.005 | 0.907 (0.848–0.971) |
| Unsolvable queen problems | 3.8 (3.1–4.6) |
3.9 (3.2–4.8) |
3.6 (3.0–4.4) |
0.143 | 1.081 (0.974–1.201) |
- | |
| Dead colonies (mortality) | 7.8 (5.9–10.2) |
6.8 (5.1–9.0) |
8.9 (6.7–11.6) |
<0.001 | 0.753 (0.699–0.811) |
<0.001 | 0.802 (0.740–0.869) |
| Empty hives (CDS) | 3.7 (2.0–7.0) |
2.9 (1.5–5.6) |
4.7 (2.5–8.8) |
<0.001 | 0.611 (0.554–0.675) |
<0.001 | 0.589 (0.527–0.657) |
| No food (starvation) | 1.4 (0.7–2.7) |
1.7 (0.8–3.2) |
1.1 (0.6–2.2) |
<0.001 | 1.493 (1.251–1.781) |
<0.001 | 1.685 (1.392–2.040) |
a Controlled for the year of the study (random effect); b controlled for the year of the study and geographical region (random effects), as well as the number of colonies owned by a beekeeper, percentage of replaced queens, practice of migration of colonies, varroosis monitoring, and varroosis treatment (fixed effects).