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Rodent problems have plagued mankind for an eternity. Neil Clarkson looks at ways of getting the upper hand around stables and feed stores.
The cooler months are when the typical rat or mouse turns its attention to finding four walls and a roof to help it see through winter.
Having seen out the summer months in the wild, you can imagine their delight at stumbling upon a stable, barn, tack room or feed store.
Aside from some warmth and shelter, there’s a good chance of a few servings of nutritious grains and other hard feeds.
A fat rodent is a content one, and, unless a vigilant horse owner plans his campaign carefully, they could well find themselves not only being over-run by vermin, but out of pocket as the furry critters contaminate potentially hundreds of dollars worth of feed set aside for winter.
A rodent is likely to ruin 10 times as much food as it eats, by contaminating it with their urine, droppings, and fur. If you’re wondering how big the problem is, the US Department of Agriculture estimates more than $US2 billion in feed is destroyed by rodents each year.
Not only that, but they are likely to chew on your buildings and do damage. They can take out your electricity and even cause fires by chewing on power cables. Some fire authorities believe up to a quarter of all blazes for which a cause could not be established may have been started by vermin.
There’s also a pretty good chance they’ll have a fair old chew on winter covers and saddle blankets.
Then, of course, there is their ability to carry disease. In the 1600s about 25 million people died from bubonic plague carried by rats. Rats and mice are known to carry salmonellosis, leptospirosis, trichinosis, and, in some parts of the world, rabies. Then there are mites, ticks, lice, internal parasites, and fleas – the latter being the vector that transferred the plague from rats to people.
In short, rodents are well down the list in popularity contests .
In any battle, the first step is to know your enemy. Rats and mice are tough and adaptable.
Let’s look at them individually.
They set up residence in a nest and will range up to 50m from it. If food is plentiful, their range may be considerably less. They become familiar with their home territory and get to know it like the back of their paw. When trouble happens, they will be familiar with their escape routes. Their calling card will be up to 45 droppings a day.
They will be alert to any changes in their home environment and will naturally be very suspicious. This may mean that they will stay away from poison baits for many days before approaching, particularly if other foods are readily available.
Rats require water to drink, more so when they are eating dry foods. This is why they often live along waterways.
They tend to prefer burrows, but will take up residence in walls, ceilings – in fact any area that provides a “burrow-like” environment. Rats can squeeze through gaps as little as 13mm wide and are good climbers. They can jump about 90cm.
They will eat just about any type of food, but prefer grains and meat. When food is in short supply, they will eat just about anything that will given them energy, from plaster to soap and animal carcasses.
A rat has a typical lifespan of a year, but can live to 18 months. A female can have four litters a year, comprising six to 12 young. These are ready to reproduce after just three months, and the young are born only 22 days or so after mating.
A rat will typically eat 10 per cent of its body weight a day. This means a colony of 100 rats (the can get that big) might munch through a tonne of grain a year – enough to feed a horse for the same period.
They tend to be most active at night.
Mice tend to have much smaller home zones. They may stray only 3m from their nest, but could range up to 10m if required to obtain food. Mice tend to be more inquisitive than rats, and will tend to check out new traps and baits more readily. They will deposit up to 75 droppings a day, which makes horses, at around 20 a day, seem positively amateurish.
Mice do not need to drink. They can get enough moisture from the food they eat to survive. Come the cooler months, there is nothing a mouse likes better than spaces in walls, ceilings, even furniture.
A mouse can squeeze through a gap as little as 6 to 7mm wide – about the size of a pencil.
They are capable or running up many vertical surfaces and can run along wires with ease. They can jump up to 30cm.
Mice are born just 19 to 21 days after mating. A female mouse can produce five to 10 litters a year, each with five to six young which will be sexually mature in just six to 10 weeks.
Like rats, they are usually most active at night. They generally prefer grains and the like in their diet, but, like rats, will eat many other things if survival requires it.
Strategy 1: Can you keep the rodents out?
It would be great if we could make every building rodent-proof, but this may prove too difficult. Remember, if you can get a pencil through a gap, there’s every chance a mouse can get through, too.
Check your building over to see what options you have for rodent-proofing. Fill any holes with concrete, a durable caulking compound, a fine steel mesh, or even steel wool. Pay attention to where pipes and wires enter the building.
If the walls of your building have air vents, use a fine metal mesh which will stop rodents getting in while at the same time still allowing the wall space to breathe.
Doors and windows must not have gaps bigger than 6mm. Screw a steel kickplate along the base of doors to provide rodents chewing their way in.
Metal collars about 30cm deep should be fitted around posts to prevent rodents from climbing.
If you tend to leave your shed doors open for long periods, it’s unlikely you’ll avoid an invasion. Rodents don’t need inviting twice.
Strategy 2: Let’s be happy housekeepers
Keeping feed areas as clean as possible is an important strategy in controlling rodent numbers. The last thing you want to do is provide them with food, as well as shelter.
Vermin will chew through grain bags in the blink of an eye. Keep grain and other feeds in rodent-proof containers, such as drums or large plastic containers with snug-fitting lids.
If they get into your feed containers, they’ll destroy far more than they eat through their urine, faeces and fur.
Clean up every scrap and morsel from the floor after you’ve prepared your horse’s meals and dispose of it in a rodent-proof container.
Try, where possible, to keep hay away from stables and feed rooms, as the seeds can provide a good source of food for rodents.
Keeping food sources out of the equation will make your buildings less desirable places to live.
Strategy 3: Eliminate water
Rats may not find your premises to their liking if there’s not a ready supply of water within range of their territory (about 50m). Do everything you can to prevent water pooling. Try to keep water and food bowls away from such buildings.
Many horse owners keep cats and terriers for the specific purpose of catching rats and mice. Ironically, the food and water you put out for your cat may be the very thing that encourages the vermin to pay a visit and stay.
Strategy 4: Begin your campaign early
Most people won’t have a rodent problem in the summer. The weather is mild and food is plentiful. There’s nothing wrong with the great outdoors.
But as temperatures cool and food supplies dwindle, that’s when they come visiting.
It only stands to reason that if you begin your offensive early, you’ll have far fewer rats and mice to trap or poison. Knocking off mum and dad early can save you the trouble of knocking off dozens more in the matter of only a month or two.
Strategy 5: Blitzkrieg!
This German word means literally “lightning war” or “flash war”, a strategy used to great effect in World War 2. It’s an attack in which speed and surprise are used to good effect, preventing an enemy mounting an effective defence. The Americans in later years used the more mundane term “Shock and Awe” to mean much the same thing.
Either way, you’re running your offensive – and you need to go in hard.
Should you trap them or poison them?
In a domestic situation, trapping is probably the best option, but much will depend upon the seriousness of the infestation.
The clear advantages of trapping are that you can see if your campaign is working, and bodies are removed, eliminating any chance of nasty odours developing from rodents that die behind furniture, or in wall or ceiling spaces.
Trapping also means you don’t need to use any poisons (in this case rodenticides), and there is no risk of killing or poisoning non-target species.
However, a serious infestation will leave you little choice but to use poison. The most effective strategy is to use both poison and traps.
Whatever strategy you employ, you should disturb their habitat as little as possible, otherwise you run the risk of them simply moving to anther part of the building, or another building altogether.
First, let’s consider what trapping involves. Traps are most effective against mice, which are less suspicious than rats.
It’s important that you place the traps in the right positions. Rodents will nearly always prefer to scoot along the base of walls, rather than cutting across a room. So, traps should be placed near walls and in corners. Tell-tale droppings will indicate a good spot to set a trap. Place them where young children won’t get their fingers caught.
Bait the traps with meats such as bacon or sausage, crunchy peanut butter, even nuts or pieces of fried or fresh fruit. Chocolate is also effective. It can sometimes help if you tie bait to the trap with dental floss so it can’t be removed without triggering the trap.
For rats, it will pay to bait the traps without setting them, allowing them to get used to them before you go in for the kill.
One of the biggest mistakes people make with traps is not using enough of them. It’s important to get on top of the burgeoning population as quickly as possible, and you’ll struggle to do that with only a couple of traps.
Invest in eight or 10 around your stables. Keep the bait fresh and, if you’re not having success with a spot, move the trap to another area.
A serious infestation will keep you very busy emptying traps. There is a rule of thumb that for every rat or mouse you see, there are probably 20 to 25 others in hiding.
When handling the traps and dead mice, wear well-sealed rubber or plastic gloves and dispose of them in plastic bags in a rubbish container that has a tightly sealing lid.
This is the most effective way of tackling large numbers, but it is important you understand the risks. Crucially, you must ensure that animals other than rats or mice do not get access to the poison.
There are a number of poisons on the market, which come in different forms. Some come in small blocks that you can lay out, others in impregnated grains or granules. In all cases the poison material will contain a dye indicating that the product contains poison. Grain, for example, may be blue or green.
Some poisons will kill with one feed; others may require a rat or mouse to eat the poison over several days before a kill is achieved.
Warfarin used to be one of the most popular rodenticides, but rodents are building a resistance to it. Other poison agents are now being used.
Read the instructions on the pack with great care and follow them to the letter.
If you discover that a child or pet has ingested some poison, follow the first-aid advice on the container. This may vary, depending upon the rodenticide used. Urgent action will be require. Call your hospital, the National Poisons Centre, or local veterinary clinic immediately and have the container handy so you can immediately tell them what poison is involved.
Take the container with you when you take your child or pet for treatment, so the experts know what they are dealing with.
Like traps, poison bait should be placed around the bases of walls and in ceilings or crawl spaces. If you’re placing it in your tack or feed rooms, place the bait behind large objects, such as feed drums, where children and pets cannot reach. There is a real risk that a pet dog will decide that the bait is to their liking.
Cats are far less likely to consume bait, but can be poisoned by eating a rodent that has been killed by your bait.
Bait stations can be bought that will make access to the poison extremely difficult for childrens and pets.
It’s a good idea to keep a written note, or map, of where you’ve laid your bait, so you can collect any leftovers once your campaign is over. Bait stations are the only option when using poison outside and should be clearly labeled as containing poison.
If you think you’ve come across a rat hole, stuff it with leaves or newspaper and check the next day to see if the material has been disturbed. If so, throw poisoned grain deep down the burrow. Don’t use large block baits in this situation, as the rats may kick it out of their nest, where other animals may eat it.
Liquid baits can be obtained, which are particularly effective if access to water is limited. Again, it is essential that no other animals can access the water. You may not consider this a safe option around your stable.
If you’re unable to keep rodents out of your sheds, your campaign against rodents will be an ongoing one during the cooler months.
The key things are:
- Start your campaign early.
- Keep food spillages to a minimum.
- Take great care in the use of poisons, and follow all instructions to the letter.
- Pay attention to hygiene in handling traps and carcasses, and dispose of rodent bodies in a way that other animals cannot access them.