Effect of nutritional plane on health and performance in dairy calves after experimental infection with Cryptosporidium parvum.

OBJECTIVE To evaluate the effect of nutritional plane on health and performance of dairy calves after infection with Cryptosporidium parvum. DESIGN Randomized, controlled trial. ANIMALS 20 Holstein bull calves. PROCEDURES Calves were assigned to a higher plane of nutrition (HPN; 0.30 Mcal intake energy/kg of metabolic body weight using a 28% protein-20% fat milk replacer) or conventional nutrition (CN; 0.13 Mcal intake energy/kg of metabolic body weight using a 20% protein-20% fat milk replacer). Calves were inoculated with C parvum oocysts at 3 days old. Fecal and health scores, oocyst counts, weight gain, dry matter intake, and hematologic variables were measured for 21 days. Data were analyzed with nonparametric and regression methods. Results-Body weight (day 1), serum total protein concentration (day 3), and PCV (day 3) were not different between groups. Oocyst shedding was not different between groups. The PCV was higher in the CN group (40%), compared with the HPN group (32%) at the end of the study. Fecal scores (FS) improved faster in the HPN group (median, -0.1 FS/feeding), compared with the CN group (median, -0.06 FS/feeding). The HPN calves had better average daily gain (ADG) than did CN calves (median, 433 g/d vs -48 g/d, respectively). Feed efficiency (ADG:dry matter intake ratio) was better for HPN calves than CN calves (median, 131.9 g/kg vs -31.4 g/kg). CONCLUSIONS AND CLINICAL RELEVANCE After a pathogen challenge, calves maintained hydration, had faster resolution of diarrhea, grew faster, and converted feed with greater efficiency when fed a higher plane of nutrition.