Evaluating the economic profit of reproductive performance through the integration of a dynamic programming model on a specific dairy farm

The overall objective of this study was to improve the reproductive efficiency of lactating dairy cows and to improve the resulting total farm profit. The hypothesis is that a dairy farm can substantially improve its economic and environmental performance through increasing pregnancy rate, i.e. increasing the number of eligible cows that become pregnant for a given breeding period. This paper presents a tool which was designed with a view to comparing the reproductive efficiency. The tool was developed using dynamic programming in R (Shiny) and shows the changes in costs, revenues and net return projected for a given change in pregnancy rate. The model calculates from the first day in milk and stops when the last calf was born after successful insemination of each cow. Sensitivity analyses demonstrated that the economic return associated with reproductive performance is greatly affected by the input parameters and therefore real farm and market values are crucial. The average economic gain per percentage point of 21-d (21-day) pregnancy rate (PR) was 14.6 EUR per cow/year. The milk price showed the largest impact on the overall net return. A 10% increase in milk price increased the net return on average by 268 EUR (10% 21-d PR), 292 EUR (20% 21-d PR) and 299 EUR per cow/year (30% 21-d PR). Our study had the same set values of milk yield during lactations for all four evaluated farms and it was found that the milk income over feed cost increased with the reproductive performance in all evaluated farms on an individual cow level. Poor fertility means that cows spend longer producing lower amounts of less efficiently produced milk.