Table 1.
Default input parameters of reproductive, productive, and culling modules of the model.
| Parameter | Distribution | Value |
|---|---|---|
| Pregnancy probability (per 21 d) 1 | Discrete | 0.16 |
| Probability of abortion by month of gestation (n = 2 to 8) 1,2,3 | Discrete | 3.5, 2.5, 1.5, 0.5, 0.25, 0.1, and 0.1%, respectively |
| Milk Production (kg) 3 | Incomplete gamma curve (Wood’s model) 4 | MDIM = a(DIMb)(e−(c)(DIM))—Curve fitting based on herd data input |
| Pregnancy length (days) | Constant | 280 |
| Dry-off probability at 225 days of pregnancy 5 | Discrete | 1.0 |
| Culling probability | ||
| Involuntary 3 | ||
| First parity | Polynomial | y = 2 × 10−9 × DIM3 − 3 × 10−7 × DIM2 − 1 × 10−5 × DIM + 0.0112 |
| Second–fourth parity | Polynomial | y = 9 × 10−10 × DIM3 + 7 × 10−7 × DIM2 − 0.0002 × DIM + 0.0183 |
| Fifth parity | Polynomial | y = 2 × 10−10 × DIM3 + 1 × 10−6 × DIM2 − 0.0003 × DIM + 0.0266 |
| At the end of Fifth parity | Constant | 1.0 |
| Non-pregnant with DIM > 300 | Constant | 1.0 |
| After the abortion | Constant | 1.0 |
M = Milk Yield; DIM = Days in milk; a = Scale factor for initial milk yield; b = Rate factor for the increase in milk yield to peak; c = Rate factor for the decline in milk yield after the peak.1 Adapted from De Vries et al. [25]. 2 Adapted from Santos et al. [24]. 3 Piccardi, 2014 [26]. 4 Wood, 1967 [27] 5 Kalantari and Cabrera [15].