Table 2.
Descriptive statistics for production, efficiency, and economic variables from 1000 iterations of a 100-cow herd.
| Variable | Mean | SD | Min | Max |
|---|---|---|---|---|
| Production | ||||
| Cycling in first 21 days, % | 88.11 | 3.93 | 71.41 | 96.23 |
| Postpartum interval, d | 59.2 | 3.8 | 45.7 | 70.3 |
| Pregnancy percentage, % | 92.96 | 0.95 | 88.92 | 95.68 |
| Calved in first 21 days, % | 59.40 | 2.74 | 47.75 | 65.71 |
| Median BCS at calving | 5.8 | 0.3 | 5 | 6 |
| Median BCS at weaning | 4.4 | 0.4 | 4 | 6 |
| Cull cow age, y | 6.6 | 0.4 | 5.5 | 7.8 |
| Replacement heifers required, % | 15.74 | 0.89 | 13.16 | 19.06 |
| Actual weaning weight of calves, kg | 207.8 | 4.6 | 194.6 | 224.0 |
| Supplement used, kg/cow | 421.5 | 104.2 | 146.8 | 726.4 |
| Winter feed used, kg/cow | 1850.2 | 117.2 | 1486.9 | 2236.5 |
| Total purchased feed, kg/cow | 2271.7 | 61.7 | 2085.4 | 2454.6 |
| Efficiency | ||||
| Grazing days per ha, d | 10.5 | 0.4 | 9.3 | 11.8 |
| Dry matter intake per kg weaned, kg/kg | 26.49 | 0.70 | 24.46 | 28.78 |
| Kg weaned per cow exposed, kg | 172.4 | 4.6 | 158.1 | 189.0 |
| Kg weaned per grazed ha, kg | 60.8 | 1.5 | 56.1 | 67.2 |
| Economic | ||||
| Revenue, USD/cow | 708.12 | 12.36 | 675.94 | 754.60 |
| Supplement cost, USD/cow | 77.63 | 20.04 | 25.94 | 134.14 |
| Winter feed cost, USD/cow | 307.81 | 24.55 | 236.42 | 393.46 |
| Purchased feed cost, USD/cow | 385.44 | 22.56 | 320.99 | 470.54 |
| Replacement cost, USD/cow | 110.09 | 6.45 | 91.09 | 131.77 |
| Interest expense, USD/cow | 31.80 | 1.21 | 28.00 | 36.40 |
| Total variable cost, USD/cow | 667.82 | 25.23 | 592.83 | 762.38 |
| Returns 1, USD/cow | 40.30 | 29.00 | −76.57 | 130.20 |
| Returns 1, USD/grazed ha | 14.28 | 10.25 | −27.45 | 46.16 |
| Annual ROI, % | 8.01 | 4.58 | −8.10 | 23.47 |
SD = standard deviation; Min = minimum value; Max = maximum value; BCS = body condition score, 1 = thin, 9 = obese. 1 Returns are calculated as revenue minus variable costs (i.e., returns over variable costs).