TECHNICAL AND ECONOMIC-MODELS TO SUPPORT HEIFER MANAGEMENT DECISIONS - BASIC CONCEPTS

To maximize herd profits, dairy farmers are faced with the complex dil emma of minimizing costs that are associated with rearing heifers whil e ensuring or enhancing lifetime economic productivity. Decisions abou t heifer management interact with underlying biological aspects of gro wth, thereby influencing future profitability. A thorough understandin g of these biological interactions is lacking. Studies based on models could be useful in the evaluation of various rearing strategies. Curr ently available models for dairy cattle primarily focus on the dairy c ow. In a dairy farm production system, management decisions concerning the rearing of livestock and the replacement of dairy cows strongly i nfluence each other. In a model that describes the dairy herd as a mul tiple-component system, opportunity is greater to coordinate rearing a nd replacement policies. Expected benefits of such a model are discuss ed.