aDanish Institute of Animal Science, DK-8830, Tjele, Denmark bDepartment of Clinical Studies, Division of Large Animal Medicine, The Royal Veterinary and Agricultural University, Bülowsvej 13, DK-1870, Frederiksberg C, Denmark
A dynamic, stochastic model simulating the technical and economic consequences of bovine virus diarrhoea virus (BVDV) infections for a dairy cattle herd for use on a personal computer was developed. The production and state changes of the herd were simulated by state changes of the individual cows and heifers. All discrete events at the cow level were triggered stochastically. Each cow and heifer was characterized by state variables such as stage of lactation, parity, oestrous status, decision for culling, milk production potential, and immune status for BVDV. The model was controlled by 170 decision variables describing biologic and management variables including 21 decision variables describing the effect of BVDV infection on the production of the individual animal. Two markedly different scenarios were simulated to demonstrate the behaviour of the developed model and the potentials of the applied modelling principle. The validation problem in relation to the model was discussed. A comparison between real and simulated data using data from a published case report was shown to illustrate how user acceptance can be obtained.
This article was published in Preventive Veterinary Medicine, 23, Jan Tind Sørensena, Carsten Enevoldsena and Hans Houeb, A stochastic model for simulation of the economic consequences of bovine virus diarrhoea virus infection in a dairy herd, 215-227, Copyright Elsevier 1995.