Estimation of the within-herd transmission rates of bovine viral diarrhoea virus in extensively grazed beef cattle herds

Table 1 Definition and value of parameters used for within-herd BVDV transmission model

Parameter definitions	Value	References
Oestrus cycle (day)	U(18, 24)	[31]
Probability of conception	0.62	[33]
Natural abortion rate	0.0001 per day	[34, 35]
Natural calf mortality rate until weaning	0.0009 per day	[36]
\(\beta_{P}\): Within-herd BVDV transmission rate (per PI animal per day)	To be estimated
\(\beta_{T}\): Within-herd BVDV transmission rate (per TI animal per day)	\(\beta_{P} \times 0.05\)	[10, 27]
Infectious period of TI animals (day)	U(10, 20)	[28,29,30]
Period of maternal BVDV antibody protection (day)	N(155, 31²)	[37, 38]
Mortality rate of PI animals	0.0019 per day	[6, 9]
Probability of abortion if infected during early pregnancy (day 0–41)	0.8	[52, 53]
Probability of abortion if infected during mid-pregnancy (day 42–150)	0.25	[52, 53]
Probability of calving PI animal if infected during mid-pregnancy	0.934	[2, 52]
Probability of calving an immuned calf if infected during mid-pregnancy	0.033	[2, 52]

Key: N(·,·), normal distribution(mean, variance); U(·,·), uniform distribution(lower limit, upper limit).

ISSN: 1297-9716