Effects of interrelationships of production and reproduction on net returns in Florida

Economic aspects of reductions in reproductive efficiency associated with increased production of milk and fat were evaluated for Holsteins and Jerseys in Florida during warm and cool seasons. Net returns from sire selection for increased production were examined with and without incorporation of such negative effects. The economic framework is the application of risk analysis in portfolio selection to selection of dairy sires. Estimates of effects of production on reproduction were from an earlier study of 4293 Holstein and 2143 Jersey cows in first lactation on 14 Florida dairy farms in warm and cool seasons. The scenario represented the typically low reproductive efficiency of cows, especially Holsteins, during summer in Florida, although some statistics used represented US values. Least squares estimates of net returns after adjustment for reproductive losses showed major reductions in net returns for both breeds for both seasons, for example, $28 to $30/yr per lactation, representing 47 to 53% of predicted net returns for Holsteins and 27 to 31% for Jerseys. The results also suggested that increased use of young sires, which results generally in higher conception rates and lower semen costs, might be justified in tropical and subtropical areas, particularly during hot seasons.