Figure 1

a – Proportion of all colics and impaction colics during each month of the year from January 2000 until March 2005. b – Time series analysis of the proportion of impaction colics during each month from January 2000 until March 2005. Plot shows proportion of impaction colics per month (open circles), fitted values from the regression model with 12 month cycle (red line) and raw data after smoothing with 3 month moving average (black line) which demonstrates a 12-month seasonal pattern in the occurrence of impaction colic with a peak in late autumn.