Analysis of censored data for such as colostral immunoglobulin transfer in calves.

Passive immunity in the neonatal calf is dependent upon colostral immunoglobulin transfer into the systemic circulation. Critical in this transfer is the period of absorption, which is dependent upon age of initial feeding of the calf and amount fed. For some calves known only was that absorption extended beyond duration of the experiment, causing the data to be censored. Analysis of the length of absorption showed a two-phase regression model when censored data were used with uncensored data. Incorrect inferences may be drawn if censored data are not incorporated into the analysis.