In general, first-generation anticoagulant rodenticides can be described as chronic rodenticides because repeated feeding is needed to deliver a lethal dose. This characteristic requires a constant supply of bait and frequent replacement, a technique known as surplus, or saturation, baiting (Dubock 1984).
Second-generation anticoagulant rodenticides are more potent, so it is possible for target rodents to consume sufficient bait for a lethal dose in a single feed. A comparative assessment of a range of second-generation rodenticides found that efficacy is directly related to the acute toxicity of the baits (Greaves et al., 1988). Table 16 provides a comparative summary of the amount of feed required to be consumed for an LD50 for a range of rodenticides against house mice (Mus musculus) and Norway/brown rats (Rattus norvegicus). The use of compounds with a lower feed requirement provides control with comparatively smaller amounts of bait and less labour. When rodents eat less bait, lower levels of residues could reduce the risk of secondary poisoning and contamination (Dubock 1984).
The physical control methods described above can be used to supplement existing rodent control programs. However, given the level of vermin attracted to poultry operations, they are unlikely to provide a sufficient level of control on their own.
