We are approaching the time of year when livestock start moving indoors and the days become cooler and wetter. It is at this time of year that rodent populations around the farmyard tend to increase dramatically.

Rodents are prolific breeders and, if are not adequately managed, several rats can turn into an infestation before you realise. They pose massive risks to human and animal health, being able to carry a range of parasites and pathogens, including Weil’s disease, salmonella and brucellosis.

That is why it is essential that every farm has a good rodent pest management plan. It is also worth noting that farmers partaking in the Bord Bia Quality Assurance scheme are required to control pests in the farmyard.

Controlling rodents such as rats and mice using rodenticides comes with a certain amount of risk. The Campaign for Responsible Rodenticide Use (CRRU) is in place to reduce rodent numbers in a responsible fashion that prevents exposure to other wildlife.

Contamination can occur when a non-target species consumes bait directly (primary exposure) or when a predator consumes an animal which has been previously exposed (secondary exposure).

The CRRU has a number of guidelines for rodent control, which can be found online at www.crru.ie.

The main point to note is have a plan. Do a thorough survey of the infected site and place bait points in the most likely high-traffic rodent areas. Changes to the immediate environment should be considered after the treatment, ie removing rubbish and weeds that provide cover.

However, the site should not be cleared before treatment, since this will disturb the rodent population and make bait acceptance more difficult to achieve.

Rodenticide baits should only be used for as long as is necessary to achieve satisfactory control.

In most cases, any anticoagulant bait should have achieved control within 35 days. Proper bait stations should be used to avoid accidentally poisoning other mammals and birds.

The bodies of dead rodents should be removed; if eaten by predators or scavengers, they may be a source of secondary exposure to rodenticides.