These pests contribute to the spread of pathogens in livestock, creating an epidemiological bridge between wild animals and birds, and between different batches of animals. As a consequence, rodents can spread infections to successive flocks in all-in, all-out systems.

Within the field rodents, we mention those known as voles. The voles include several species whose incidence in the destruction of crops is local and sporadic. They begin to reproduce at 2 months of age with a gestation of 21 days, being able to give from 2 to 7 litters per year composed of 5 to 14 descendants.

In one year of average reproductive life, a couple can give rise to more than 1,000 offspring.

Rodents are nocturnal animals and live in hidden places. They are capable of adapting their cycle of activity to the environment in which they live and, in this way, they only appear when man has left that place.

Pig farms offer shelter and plenty of food so rat infestations can actually be of economic importance. On farms, rat populations have been estimated at over 1,500. In 24 hours, this population would be able to consume 30 kg of food, produce 30,000 feces and a minimum of 15 liters of urine.

The losses produced by rodents are not only due to the food they consume, but also due to the food they contaminate and the damage they do to the facilities -loss of insulating capacity, deterioration of wiring, leaks in drinking water pipes and over all as vectors of certain diseases.

The mouse lives in local groups and are only active a few meters from their nest. They do not usually move from one farm to another. The common rat often uses a wide expanse of land.

Research has revealed that the common rat could travel a distance of 1,500 meters in a few hours. They could visit different enclosures, warehouses and ships in one night. Consequently, foreign rats could visit a farm that does not have any population on its property.

The common rat must be one of the objectives within the control measures during an epizootic outbreak

Strategic Rat Control of Rodent Control

Successful rat control depends on a clear understanding of rat behavior in relation to the epidemiological situation on a farm.

Area Under Observation

  • A general rat control campaign should be announced.
  • Each owner should devise a comprehensive plan for rat control.
  • The more farms (even if they are of different species, poultry, pigs, etc.) simultaneously carry out control measures, the greater the success of the campaign.
  • Farms should store enough bait to carry out the campaign.

Farms in Prohibited Area

  • There is a risk of rats entering the property after leaving a farm with a bulb. This has to be prevented by intensifying a control perimeter around the farm buildings.
  • All bait stations should be filled with 200g of bait and monitored twice a week.

Farms With Infectious Outbreaks

Intensive rat control should be done before disinfection, slaughter and sanitation. The rats will leave the farm when the cattle are slaughtered and the farm is disinfected. As a consequence, there is a risk that they act as vectors at a distance of more than several kilometers in a few days.

The rat can carry pathogens to a farm that is inside or outside the prohibited area. It is imperative that intensive rat control begin as soon as possible after an outbreak is suspected. Looking at it carefully, in extreme epidemic situations, placing the greatest amount of rodenticide inside the buildings, even without protection or in bait boxes, is recommended and justified.

The bait should be replenished daily. Domestic animals (dogs and cats) should not be allowed to move freely in the affected area. An additional ring around the farm perimeter will reduce the risk of rat migration. It is important to track and document eradication to simplify and authorize the purchase of new livestock. In farms where a large amount of food is available, only highly palatable baits should be used.

In addition to their power to eradicate rat infestation, such baits can also be used for monitoring and control by showing obvious signs of consumption, even of small amounts.

Application and Rat Control

Baits should be distributed throughout the farm to allow all rats to have access to a sufficient amount of bait. Often this is not the case because baits are only placed where rats have been seen or where their activity is obvious.

As a result, the rats are not eliminated immediately and the population quickly recovers. Research has revealed that the location of baits on farms must follow a systematic plan. Throughout the farm, a bait should be placed at least in every place where rats are likely to appear. These points must be inspected twice a week for more than six weeks and the bait that is eaten must be replaced.

It is helpful to draw a map of the farm and mark with a number all the points where a bait has been placed. It is recommended that the amount of rodenticide per bait point and the residence time be recorded in a report.

The elimination of rodents is very important within biosecurity and must be considered as a critical control point in systems.

Development Plan of a Rodent Control Program

Thorough Inspection

We must detect transit sites, breeding and refuge areas. Detect droppings, footprints, burrows, structural damage to the installation (such as wiring, PVC pipes, insulation, etc.), escape routes. Also, if possible, rodent viewing. This is more feasible to do at sunset or dusk since we have mentioned that the rats have nocturnal habits.

Identification of the Pest and Assessment of the Problem

It is important to know the type of rodent we are dealing with and even estimate the number of individuals. This will make it easier for us to place the bait holders and even the number of them that we will need, in addition to knowing how much rodenticide we will need.

Make a Map

From where we have strategically placed all the bait stations. Research has revealed that the location of baits on farms must follow a systematic plan.

In places where rats are more than likely to appear, the incorporation of a bait is recommended. Inspection of these baits should be done twice a week, replacing those that have been consumed by rodents. It is helpful to draw a map of the farm and mark with a number all the points where a bait has been placed.

It is recommended that the amount of rodenticide per bait point and the residence time be recorded in a report. This document will allow future control measures to be improved and could be used as proof of good hygiene practice in accordance with biosafety and food hygiene requirements.

Choice of Type of Rodentsident

Keep in mind that rodents have a large quantity and variety of food on our farms. Therefore, the most important property in a bait is its degree of attraction/palatability for rodents.

The palatability of a rodenticide is a very important point to choose one type of rodenticide or another. In addition, we must take into account where and when we are going to apply it. In pig facilities we must act on different fronts and therefore we must handle different presentations regardless of the active ingredient.

Types of Rodenticide According to Their Action

Fast Action Treble

Requires a single ingestion to cause death. Causes death within a few minutes to a few hours after ingestion. Death from respiratory arrest or generalized paralysis. Act on CNS Relatively high concentrations required. Danger due to its high toxicity and low selectivity. High risk of “bait fright” (survivors or those who see their peers suffer, do not eat the bait again even if they die of hunger and, in addition, they warn the rest of the group)

Slow Acting Chronic

Multiple ingestions to cause death Most are anticoagulants, except cholecalciferol. High accumulative power. Activity from very low doses and with good acceptance. No action on the CNS the animals do not suffer there is no distrust of the bait Delayed mortality they do not relate death to the consumption of the bait.

Commercial Presentations of Rodenticides

In the market we find different forms and presentations, regardless of the active ingredient. The type of presentation is important when choosing a rodenticide to be successful in a rodent control program.

We must also bear in mind that we are handling toxic products, especially abroad, for this reason we will take extreme precautions and use specific bait stations to apply this type of product, avoiding poisoning in other species (domestic animals and even people).

The problem with fast-acting rodenticides is that rodents may associate death with poison ingestion. That is, the rats associate the death of their congeners with the ingestion of the bait. For this reason, currently the rodenticides that are used are anticoagulant substances. The rats die after several days to prevent rodents from associating death with ingesting the bait and thus avoid rejecting it.