Characteristic | Cow model | Goat model | |
---|---|---|---|
Herd size | 50 | 770 | |
Birth-birth interval | 55 weeks | 52 weeks | |
Birth season | year-round | 12 weeks | |
Gestation period | 40 weeks | 21 weeks | |
Non-gestation period | 15 weeks | 31 weeks | |
Dry period | 8 weeks | - | |
Young animals | no heifers in the model | includes youngstock | |
Environment | 2 environments | 1 environment | |
Replacement rate (year-1) | 0.355 | 0.305 | |
Culling rate (week-1) | Lactation or age 1 | 0.0057 | 0.0029 |
Lactation or age 2 | 0.0052 | 0.0029 | |
Lactation or age 3 | 0.0065 | 0.0029 | |
Lactation or age 4 | 0.0067 | 0.0136 | |
Lactation or age 5&6 | 0.0161 | 0.0136 | |
Lactation or age 7&8 | NA | 0.0136 | |
Probability distribution of the lactation numbers (for cows) or age (for goats) at the start of simulation | Lactation or age 1 | 0.337 | 0.285 |
Lactation or age 2 | 0.252 | 0.245 | |
Lactation or age 3 | 0.173 | 0.211 | |
Lactation or age 4 | 0.11 | 0.136 | |
Lactation or age 5 | 0.088 | 0.067 | |
Lactation or age 6 | 0.04 | 0.033 | |
Lactation or age 7 | NA | 0.016 | |
Lactation or age 8 | NA | 0.008 | |
Infection from the environment | p = 1 – exp(−E(t)) | p = 1 – exp(−Ê(t)/N) | |
Quantity of bacteria released by shedders in low, mid and high levels respectively, expressed in dimensionless units. | 1, 1/30, or 1/3000 | 1*50, (1/30)*50, or (1/3000)*50 | |
Probability of abortion | 0.02 | 0.02*(40/21) |