Evaluation of factors associated with the risk of infection with Cryptosporidium parvum in dairy calves

Abstract

To identify risk factors associated with Cryptosporidium parvum infection in dairy calves. 108 case animals and 283 control animals. Case animals were calves infected with C. parvum, and controls were infected with Cryptosporidium bovis (n = 67) or calves not infected with Cryptosporidium spp. Fecal samples were tested via the flotation concentration method for Cryptosporidium spp. Samples were genotyped by sequencing of the 18s rRNA gene. Associations between host, management, geographic, and meteorologic factors and Cryptosporidium genotype were assessed. Younger calves and calves housed in a cow barn were more likely to be infected with both genotypes. Herd size and hay bedding were associated with an increased risk of infection with C. parvum, and Jersey breed was a risk factor for C. bovis infection. Compared with a flat surface, a steeper slope was significantly associated with a decreased likelihood of infection with both genotypes, and precipitation influenced the risk of C. parvum infection only. Risk factors for calf infection with C. parvum differed from those for infection with C. bovis. Results may be useful to help design measures that reduce animal exposure and decrease public health risk and economic losses associated with C. parvum infection in cattle.