Neospora caninum Seroprevalence in Iowa Feedlots and its Association with Morbidity, Mortality, Production Parameters and Carcass Traits

Abstract

Since first recognized in 1984 and described as a cause of bovine abortion in 1989, N. caninum has emerged as a leading cause of abortion in cattle worldwide. Traditionally, the economic impact of Neospora infection on beef productivity has been thought to be limited to the costs of abortion and increased culling. However, recent studies of Texas-based feedlot cattle described an association between the presence of N. caninum antibodies and reduced average daily gain, live body weight and hot carcass weight at slaughter. Seropositive feedlot steers, while exhibiting similar morbidity and mortality rates as seronegative steers, also demonstrated higher treatment costs if sick compared to seronegative sick calves. The purpose of this study was to test the null hypothesis that N. caninum seropositive Iowa feedlot cattle had similar morbidity rates, mortality rates, treatment costs, production parameters and carcass traits compared to seronegative cohorts. We also examined the hypothesis that the occurrence of chronic disease was equal between Neospora caninum serologically positive and negative animals.