Nonsteroidal anti-inflammatory drug therapy for neonatal calf diarrhea complex: Effects on calf performance

Todd, C. G.; Millman, S. T.; McKnight, D. R.; Duffield, T. F.; Leslie, K. E.

Three models for starter ration intake were constructed: time to starter consumption, rate of starter consumption, and total starter intake over the study period. Time to starter consumption was defined as the number of days after developing diarrhea that each calf took to consume a minimum of 100 g of calf starter ration for 2 consecutive days. Median time to starter consumption was determined based on Kaplan-Meier survival function estimates. Cox proportional hazards regression analysis was conducted to examine the association between treatment and time to starter consumption, while controlling for the effects of significant covariates. An exact method was used to handle ties between calves that began consuming calf starter ration on the same day. Rate of starter consumption was modeled using a normal distribution and identity function. Inclusion in this model was conditional on calves satisfying the time to starter consumption criteria. Finally, a GLM was constructed to evaluate total starter ration intake over the 8-wk study period.