Table 4 Results of multivariable random-effect Weibull model for risk factors of culling in 107,835 multiparous dairy cows in 173,773 lactations (herds n = 409)
From: Culling reasons and risk factors in Estonian dairy cows
Variable | Category | Na,b | Hazard Rate Ratio | 95% Confidence Intervals | P-value | Likelihood ratio test p-value |
|---|---|---|---|---|---|---|
Animal level variables | ||||||
Breeda | Estonian Holstein | 85,879 | 1 | |||
Estonian Red and Estonian Native | 21,956 | 0.84 | 0.81; 0.87 | < 0.001 | < 0.001 | |
Relative milk yield breeding valuea | < 90 | 23,731 | 1 | < 0.001 | ||
90–96 | 23,607 | 0.97 | 0.94; 0.997 | 0.028 | ||
97–104 | 27,319 | 0.94 | 0.91; 0.97 | < 0.001 | ||
≥105 | 27,704 | 0.88 | 0.86; 0.91 | < 0.001 | ||
Not estimated | 5474 | 0.94 | 0.88; 0.99 | < 0.001 | ||
Calving yearb | 2013 | 56,644 | 1 | < 0.001 | ||
2014 | 58,792 | 1.08 | 1.06; 1.10 | < 0.001 | ||
2015 | 58,337 | 1.05 | 1.02; 1.07 | 0.001 | ||
Abortion in previous lactationb | No | 172,949 | 1 | |||
Yes | 824 | 0.86 | 0.76; 0.98 | 0.025 | 0.025 | |
Previous calving interval (increase of ten days, in months) (centered) | 1.03 | 1.03; 1.04 | < 0.001 | < 0.001 | ||
Square term centered value of previous calving interval (increase of ten days, in months) (centered) | 0.99998 | 0.99983; 0.99994 | < 0.001 | < 0.001 | ||
Parityb | Second | 66,191 | 1 | < 0.001 | ||
Third | 46,171 | 1.38 | 1.34; 1.42 | < 0.001 | ||
Fourth | 29,511 | 1.81 | 1.76; 1.87 | < 0.001 | ||
Fifth | 16,868 | 2.22 | 2.14; 2.29 | < 0.001 | ||
Sixth | 8566 | 2.49 | 2.39; 2.60 | < 0.001 | ||
≥Seventh | 6466 | 3.13 | 2.99; 3.28 | < 0.001 | ||
Calfb | Female | 75,311 | 1 | < 0.001 | ||
Male | 82,247 | 1.05 | 1.03; 1.07 | < 0.001 | ||
Stillbirth | 9063 | 1.74 | 1.68; 1.81 | < 0.001 | ||
Twins/triplets | 6655 | 1.35 | 1.29; 1.42 | < 0.001 | ||
Abortion | 497 | 2.69 | 2.34; 3.10 | < 0.001 | ||
Assisted calving x periodc | No, < 7 days | 159,057 | 1 | < 0.001 | ||
No, > 7 days | 154,449 | 0.51 | 0.49; 0.53 | < 0.001 | ||
Yes, < 7 days | 14,670 | 2.34 | 2.16; 2.55 | < 0.001 | ||
Yes, > 7 days | 13,838 | 0.59 | 0.56; 0.62 | < 0.001 | ||
Milk somatic cell count at last test-milking in previous lactation (*1000/ml)b | < 200 | 1 | ||||
≥200 | 1.21 | 1.18; 1.23 | < 0.001 | < 0.001 | ||
Days in milk during last test-milking in previous lactation (days)b | 0.998 | 0.9978; 0.998 | < 0.001 | < 0.001 | ||
Milk yield at last test-milking in previous lactation (kg)b | 0.99 | 0.989; 0.99 | < 0.001 | < 0.001 | ||
Milking method at last test-milking of previous lactationb | Milking twice a day | 1 | < 0.001 | |||
Milking three times a day | 0.96 | 0.89; 1.04 | 0.303 | |||
Robot milking | 0.83 | 0.78; 0.89 | < 0.001 | |||
Age at first calving (months) (centered) | 1.02 | 1.02; 1.03 | < 0.001 | < 0.001 | ||
Square term centered value of age at first calving (months) | 0.9995 | 0.9991; 0.9999 | 0.024 | 0.024 | ||
Herd level variables | ||||||
Change of herd size from 2013 to 2015a | No change (±5%) | 48,548 | 1 | < 0.001 | ||
Decrease > 5 to 15% | 16,286 | 1.06 | 0.92; 1.21 | 0.444 | ||
Decrease > 15% | 12,204 | 1.33 | 1.15; 1.54 | < 0.001 | ||
Increase > 5 to 15% | 16,922 | 0.89 | 0.77; 1.02 | 0.091 | ||
Increase > 15% | 13,875 | 0.82 | 0.70; 0.95 | 0.008 | ||
Herd average calving interval (increase by 10 days) | 0.97 | 0.95; 0.98 | < 0.001 | < 0.001 | ||
Herd average number of cows (increase by 50 cows) | 1.02 | 1.01; 1.03 | 0.002 | 0.002 | ||
Herd average milk yield (increase by 500 kg) | 1.04 | 1.02; 1.06 | < 0.001 | < 0.001 | ||
Herd average number of lactations (years) (centered) | 0.49 | 0.42; 0.57 | < 0.001 | < 0.001 | ||
Square term centered value of herd average number of lactations (years) | 1.11 | 1.06; 1.17 | < 0.001 | < 0.001 | ||
Regiona,d | North-East | 43,015 | 1 | < 0.001 | ||
South-East | 23,039 | 0.82 | 0.73; 0.93 | 0.001 | ||
South-West | 25,206 | 0.82 | 0.74; 0.90 | < 0.001 | ||
North-West | 16,575 | 0.90 | 0.81; 1.01 | 0.076 | ||