A model to estimate the performance, revenues and costs of dairy cows under different production and price situations

A model was constructed and validated to determine the course of performance, revenues and costs of dairy cows with different levels of milk production and of number of days open. For each month in lactation the revenues from milk production, which are dependent on the fat and protein contents, were determined. The feed costs were calculated from consumption of roughage and concentrate, which were estimated from the energy requirements. Furthermore, the course of the carcass value, calf revenues and the probability of, and the financial loss associated with, involuntary disposal were considered. Seasonal variation in production and prices was included in the model. Parameters of, and prices in, the model were chosen to represent the Black and White cows in The Netherlands at the normalized price level of 1981-1982. In the future the model will be used in studies on replacement policies in dairy cattle.