Diurnal piglet behavior of heat lamp usage was recorded by photographic time lapse technique at 15 min intervals for 24 h and expressed as the percentage of litter mates using the heat lamp. The 15 min behavioral data was then divided into subsets with a sampling interval of 30, 45, 60, 75, 90, or 120 min; and data series comprised of the averages of 15 min data corresponding to each of the augmented sampling intervals. Correlation analyses between the subsets and the average data series indicated that a sampling interval of up to 60 min results in reliable measurement of the dynamic heat lamp usage of the piglets.