Investigating losses caused by delay in calving and abortion on herd life and economic values of traits in cattle farms of Ardabil city

Abstract

Introduction: Due to the importance of more than one trait in the goals of animal breeding programs, the relative importance of each of them in changing the economic efficiency of the production system should be determined by calculating the economic coefficients of different traits. The economic value of a trait shows how much the change of the average trait in the herd by one unit affects the change of system efficiency. The decision to cull a cow is primarily based on economic considerations made by the rancher. Therefore, replacement management decisions largely determine the average productive lifespan of dairy cows. Materials & Methods: This study was conducted based on data collected through a questionnaire from dairy cattle farms in Ardabil city. The financial information and data used are based on market conditions in a production period from 2022 to 2023. In this research, the economic system of the dairy cow herd was divided into income and cost components, and an algorithm was designed to simulate the bio-economic system of the dairy cow herd using Matlab programming language. With the help of status variables, including production power in 3 levels (low production, medium production and high production) and abortion with three conditions (normal, light abortion, severe abortion) dairy cows were grouped and pregnancy delay in three grouping situations and in the planning horizon with 10 lactation periods were investigated. In order to investigate the effect of change in input values on the response of the model, a sensitivity test was used, so that the effect of a 10% change in price-related parameters on the average life of the herd was investigated. Results: The results It was also observed that the optimal decision at each production level was the same for different abortion situations. The results showed that with the increase in the price of heifers and the discount rate and decrease in the price of milk, the optimal life of the herd increases. By comparing the results of this research in the systems of production, reproduction and abortion for the studied traits with the mentioned different reports, it was observed that economic values are subject to economic conditions. So that if there is a change in the ratio of income and expenses over time, the values of the economic values will be different from the previously reported values. Conclusion: Increasing the lifespan of the herd can play a significant role in increasing the profitability of the herd through the reduction of replacement costs and the increase in the abundance of productive animals. Estimating the financial losses caused by abortion and pregnancy delay can also help in making the optimal decision to remove or keep, and improve the reproductive performance and, as a result, the profitability of the herd. The wide range of changes in the economic values of different traits over time is due to the drastic change in the prices of inputs and outputs.