A model for monitoring the condition of young pigs by their drinking behaviour

A uniform water or feed consumption pattern is required for assessment of changes in pig health and well-being. Water consumption rate was measured and monitored continuously in pigs from 4 to 11 weeks of age. The study comprised three herds and 18 batches of pigs each with 400-900 animals. The management system was ''all-in all-out''. Water consumption was measured electronically and data were transferred to a computer for time series analysis. Management interferences such as change of diet and treatment of pigs were recorded daily in a log book. The results indicated that water consumption was associated with a distinct circadian rhythm. Water consumption rate peaked between 4 and 6 pm and was lowest between 3 and 5 am regardless of herd and housing system. The circadian pattern persisted throughout the growing period while total water consumption rate increased. The pigs showed a very stable diurnal drinking pattern as long as they were healthy whereas the pattern often changed when the pigs were affected by a disease. A method using a state-space model in conjunction with a Cusum control chart is presented as a tool for on-line monitoring of young pigs, based on the water consumption. By an example it is shown that an outbreak of a disease (diarrhea) can be detected by the monitoring method approximately one day before physical signs are seen on the pigs.