A Study on wild rat behaviour and control on a pig farm

Wild rodents are known to be carriers of pathogenic organisms that affect both humans and domestic animals. In this study, two rats were followed by radio tracking for an aggregate period of 24 hours each to determine their territories, path preferences and activity levels. In addition, a video recording equipment with two cameras positioned at different locations along a pathway was used. Recordings of rat activities for 5 days were made and used to evaluate the general behaviour of wild rats around live traps and around an accessible pig pen. A bait preference study was carried out in 8 successive days of 24 hours each and pig feed was used as a control feed because of its abundance in the pig house. This was compared with four different test baits i.e. peanut butter, caviar, wax block plus walnut oil and pig feed plus walnut oil. The activity pattern in 24 hours was estimated from the bait preference study. A territory of approximately 500 m2 was recorded, as well as a path preference from the home site through the accessible burrows into the pig house. Rats also moved from the drainage system into pig pens. Furthermore, the frequent movement of rats to and from a pig pen via a low fence situated directly opposite an exit burrow was recorded. There was an evidence of pig feed plus walnut oil having the highest test bait acceptance value, followed by peanut butter, wax blocks plus walnut oil and caviar, respectively. The pattern of feeding activity estimated, showed an onset of activity after dusk which increased until about 9 pm. This was followed by a rise in activity level until it reached a peak between 3 and 4 am. Thereafter the activity level dropped steadily. In conclusion, this study agrees with previous studies on the behaviour of the wild brown rat. The results suggest that the path preferences should be a vital part of bait positioning during rodent control programmes. Wild rats should be considered to be disease risk factors to pigs whose pens they visit. Construction and maintenance of functional barriers will enhance rodent control and limit poisoning in domestic animals living on the farm. Ideally, pig feed should be adopted as the choice of base for poisoned bait on a pig farm