From: Culling reasons and risk factors in Estonian dairy cows
Variable | Category | Na,b | Hazard Rate Ratio | 95% Confidence Intervals |
---|---|---|---|---|
Animal-level variables | ||||
Days in milk at first test-milking (centered) | 1.008 | 1.007; 1.009 | ||
Square term of days in milk at first test-milking (centered) | 0.9997 | 0.9995; 0.9997 | ||
Milk yield at first test-milking (centered) (kg) | 0.96 | 0.956; 0.958 | ||
Square term of milk yield at first test-milking (centered) | 1.001 | 1.0011; 1.0013 | ||
Milk fat/protein ratio at first test-milkingb | < 1.5 | 181,507 | 1 | |
≥1.5 | 50,938 | 1.23 | 1.20; 1.26 | |
Milk somatic cell count at first test-milking (*1000/mL)b | < 200 | 174,387 | 1 | |
≥200 | 58,058 | 1.31 | 1.28; 1.34 | |
Milking method at first test-milkingb | Milking twice a day | 163,033 | 1 | |
Milking three times a day | 41,773 | 0.79 | 0.74; 0.84 | |
Robot milking | 27,639 | 0.57 | 0.53; 0.61 | |
Breeda | Estonian Holstein | 113,284 | 1 | |
Estonian Red and Estonian Native | 27,650 | 0.79 | 0.76; 0.82 | |
Parityb | First | 77,456 | 1 | |
Second | 60,689 | 2.09 | 2.03; 2.16 | |
Third | 41,267 | 2.89 | 2.79; 2.99 | |
Fourth | 25,810 | 3.65 | 3.52; 3.78 | |
Fifth | 14,398 | 4.35 | 4.18; 4.53 | |
Sixth | 7334 | 4.96 | 4.72; 5.21 | |
≥Seventh | 5491 | 6.12 | 5.80; 6.45 | |
Calving yearb | 2013 | 77,968 | 1 | |
2014 | 81,011 | 0.996 | 0.97; 1.02 | |
2015 | 73,466 | 0.95 | 0.92; 0.97 | |
Herd-level variables | ||||
Herd average number of cows (one unit change is 50 cows) | 1.01 | 1.001; 1.03 | ||
Herd average milk yield (one unit change is 500 kg) | 1.15 | 1.13; 1.17 | ||
Regiona,d | Northeast | 117 | 1 | |
Southeast | 98 | 0.87 | 0.76; 0.9993 | |
Southwest | 121 | 0.90 | 0.90; 1.003 | |
Northwest | 74 | 0.90 | 0.80; 1.02 | |
Change of herd size from 2013 to 2015c | No change (±5%) | 135 | 1 | |
Decrease > 5 to 15% | 71 | 1.03 | 0.86; 1.23 | |
Decrease > 15% | 68 | 1.48 | 1.24; 1.77 | |
Increase > 5 to 15% | 74 | 0.89 | 0.74; 1.06 | |
Increase > 15% | 62 | 0.86 | 0.71; 1.03 |