Table 5 Associations of the control variables included in the ‘trimester-based’ mixed-effects linear models for the average lactation length and average calving-to-conception interval of 127 dairy cattle herds of Treviso province, Italy, with first order autoregressive variance structure fitted to monthly measurements (January 2009 to June 2012)
Control variable | Average lactation length (days)a | Average calving-to-conception interval (days)a | ||||
|---|---|---|---|---|---|---|
Coefficient | F-value | p-value | Coefficient | F-value | p-value | |
Herd size | −4.53 | 1.51 | 0.2211 | −1.34 | 0.08 | 0.7822 |
Cows’ average age (months) | −0.12 | 0.82 | 0.3643 | −0.12 | 0.92 | 0.3381 |
Average calving-to-conception interval (days) | 0.16 | 91.00 | <.0001 | - | - | - |
Average monthly temperature | 0.94 | 168.66 | <.0001 | −0.01 | 0.02 | 0.8754 |
Proportion of pregnant primiparous cows (%) | 0.33 | 216.91 | <.0001 | −0.01 | 0.44 | 0.5086 |
Proportion of pregnant multiparous cows (%) | 0.45 | 261.98 | <.0001 | −0.07 | 8.31 | 0.0040 |
Average length of dry period (days) | −0.03 | 3.25 | 0.0717 | −0.07 | 23.67 | <.0001 |
Proportion of artificial inseminations (%) | 0.11 | 7.70 | 0.0056 | 0.42 | 114.97 | <.0001 |
Proportion of culled cows (%) | −0.42 | 52.11 | <.0001 | −0.29 | 35.20 | <.0001 |