Abstract

Dexcel's Whole Farm Model (WFM) allows the user to construct a mating policy using dates for anoestrous treatment, artificial breeding (AB) and bull mating with corresponding levels of heat detection efficiency. The model then predicts the outcome of the mating programme for each individual animal using an approach based on physiological events, represented by algorithms incorporating current best knowledge. Four commercial dairy farms were initialised in WFM by describing the farm set-up and management decisions for the 2005/06 season. A range of feeding, production and reproduction indicators was used to validate the model predictions against that observed. All four farms had an observed 3-week submission rate (SR) of about 90%. An alternative scenario with SR at80% was created for each farm by simulating reduced oestrous detection efficiency during AB. The eight scenarios were then run for 20 random simulations over three consecutive years. The trend was for SR 90% to result in more milksolids in the second and third years, improved reproductive outcomes and, despite higher AB costs, an increased (P<0.05) economic farm surplus of $80+/ha. This exercise demonstrated that the WFM is capable of simulating reproductive performance in dairy herds and holistically linking this performance to productivity and profit over successive seasons.

PC, Beukes, RM Tiddy, CR Burke, G Levy, and JAS Lancaster

Proceedings of the New Zealand Society of Animal Production, Volume 67, Wanaka, 285-292, 2007