Mortality in different management systems

Abstract

The objectives of our research are to investigate associations of mortality and culling by 60 days-in-milk with herd management systems and to evaluate the impact of sire selection on mortality rate. Herd management surveys were obtained for 314 herds that had mortality rate and 60-day culling rate data available. Mortality and 60-day culling rate were associated with five herd management systems that were identified from survey data: free-stall herds with complete confinement for lactating cows; free-stall herds with some level of outdoor access for lactating cows; tie-stall herds with complete confinement for lactating cows; tie-stall herds that fed a total mixed ration (TMR) and with outdoor access for lactating cows; and tie-stall herds that did not feed a TMR and with outdoor access for lactating cows. Mortality and 60-day culling rates were highest for free-stall herds with complete confinement (8.3% mortality) and lowest for tie-stall herds that did not feed a TMR and with outdoor access for lactating cows (2.0% mortality). Genetic selection for longer productive life reduced mortality in all management systems. The results of this and other studies suggest that intensive management systems (reduced pasture access, intensive feeding programs, free-stall housing) are associated with higher rates of mortality.