Cumulative effects of early lactation diseases on fertility and survival in a multi-state population of Holstein cows
Keywords:Endocrine, metabolism, milk synthesis, immune, calving, reproductive performance, fertility, Holstein, breed
Endocrine changes at calving and drastic metabolic adjustments to support milk synthesis result in negative energy balance and immune suppression. Consequently, a substantial proportion of cows are affected by disease around the time of calving, and most health disorders occur in the first 30 DIM. Diseases have been associated with reduced reproductive performance and increased risk of death and culling. However, large multi-state prospective studies analyzing the effect of health events by use of standardized disease definitions and times of assessment are scarce. Therefore, our objective was to test the cumulative effect of combinations of health events on fertility and survival of a large population of Holstein cows in multiple states.