Table 1.

Definitions and values of model parameters

Parameters	Values	Definitions	Sources
ρ sex	0.5	Sex ratio
a, b	8.7, 6	Parameters of the gamma distribution used to calculate the next start of pregnancy
δ	0.035	Probability of twin birth
τ He	0.02	Probability of infertility for heifers
τ Co	0.08	Probability of infertility for cows
breeding_start	15th of March	Date of start of the breeding period
breeding_dur	[16 18 20]	Duration of the breeding period (in weeks)
weaning	1st October	Date of weaning
pasture_start	1st April	Date of start of the pasture period
pasture_dur	[29 32 35]	Duration of the pasture period (in weeks)
renewal_rate	[0.286 0.317 0.349]	Ratio heifers/cows
sell_period	[autumn winter spring]	Sell period of grassers1
size	[42 83 125]	Number of bred females2
μ Ca,bi	0.0225	Probability of mortality at birth of calves
μ Ca	0.000333	Mortality rate of calves (d-1)
intro_week	[(20 25 30) 27 40]	Week of introduction of PI animal(s)3.
ε	[0.95 1 1.05]	Level of numerical productivity expected by the farmer
μ P,bi	[0.06 0.0667 0.0733]	Probability of mortality at birth of PI calves
μ P	[0.0017 0.0019 0.0021]	Mortity of PI animals per day	[20]
ϕ MS	[0.006 0.00667 0.00733]	Trantion rate from state M to state S (d-1)	[21]
ϕ TR	[0.18 0.2 0.22]	Transition rate from state T to state R (d-1)	[22]
β T	[0.027 0.03 0.033]	Daily transmission rate for T animals	[9,23]
β P	[0.45 0.5 0.55]	Daily transmission rate for PI animals	[9,24]
${\beta }_b^P$	[0.09 0.1 0.11]	Daily between-group transmission rate for PI animals	[9,25,26]
α Ra	[0.72 0.8 0.88]	Abortion rate due to infection in early pregnancy	[22,27]
α Rb	[0.18 0.2 0.22]	Abortion rate due to infection in mid-pregnancy	[28,29]
η X		Probability of giving birth to a calf in state X if infection in mid-pregnancy and no abortion	[24,28-30]
η P	[0.875 0.9375 1]
η M	[0.0625 0.03125 0]
η R	[0.0625 0.03125 0]
K ext	0	Risk of virus introduction on pasture

Nominal values are in bold. Other values are the ones tested in the model sensitivity analysis.

¹In the reference scenario, grassers were sold at the three periods: 45% in autumn, 45% in winter, and 10% in spring.

²Bred females are heifers and cows, with: 42 = 10 heifers + 32 cows, 83 = 20 heifers + 63 cows, 125 = 30 heifers + 95 cows.

³In the first case, 3 PI animals were introduced successively in weeks 20, 25, and 30. In the two other cases, a single PI animal was introduced.