Pest Animal Poisons - Protect your Dogs & Livestock
by Marjorie Orr
Thousands of tons of poisoned bait are used in New Zealand each year to poison feral mammals in many different environments from native forests to the family home. It's an unfortunate fact of life that where feral mammals are pests their numbers must be controlled by killing them. Accidental poisoning of domestic animals is then inevitably a risk, but the risk can be managed.
Heed the warnings
There are many types of poison available for pest control, but the two types most commonly used and therefore most likely to cause accidental poisoning are 1080 and anticoagulants.
Only licensed operators may use 1080, and they contact all landowners/occupiers in the area to be poisoned to warn of the risks and hazards. Before aerial drops of 1080 in carrot bait, operators put notices in the Public Notices column of local newspapers. For all operations, operators post notices around the poisoned area giving the dates of the operation and the poison used. Animal owners must heed these warnings to prevent accidental deaths of dogs and livestock.
Unlike 1080, anyone can use the anticoagulant poisons, which include Talon, Storm and Pestoff, and there is no requirement to display notices. There is no way of knowing if an anticoagulant has been laid on private land without asking the owner. This is another good reason for always asking permission before taking dogs over anyone else's land.
Most Regional Councils have information leaflets about large scale poisoning operations and information about specific operations can be obtained from the approved operator involved.
In most species, 1080 appears to be ...relatively humane. In dogs however,it causes great distress with frenzied behaviour and every indication of terror. The dog may show great agitation, with howling and trembling before the onset of fits and then death up to 18 hours after the first signs appeared. Intensive treatment by a vet can be effective, but it must be begun soon after the poison has been eaten. Untreated dogs seldom recover.
For weeks or months after 1080 poisoning operations, there is a very real risk to dogs, not just from eating bait, but also from scavenging carcases. Dogs must not be allowed access to poisoned land until it is likely that all poisoned carcases have completely decomposed. Usually this takes at least 10 weeks if there has been more than 10 cm rain, but it can take much longer in very dry or freezing weather which tends to preserve the poisoned carcases with the poison intact in the stomach. Muzzling (using a type of muzzle which allows the dog to pant) and keeping dogs under observation can help reduce the risk.
Anticoagulant poisons like Talon, Storm and Pestoff (which contain brodifacoum) and the warfarin/pindone type poisons are commonly used rat and mouse poisons, and they are also used against rabbits and possums. Often the poison is in green or blue waxy baits about the size of a pullet's egg. Anyone who uses these poisons should make every effort to ensure that other animals do not get access to the baits, and that dogs are not able to scavenge poisoned carcases.
Anticoagulants cause death through internal bleeding and there may be signs such as bleeding under the lining of the mouth, nose bleeds or lameness as a result of bleeding into the joints, and the dog becomes anaemic and weak. Fortunately, there is an antidote. Early cases of poisoning can sometimes be treated successfully with vitamin K. Treatment by a veterinarian may be protracted and expensive, but it is usually effective if started early.Make the dog vomit
If it is known that 1080 or anticoagulant poison has been eaten, making the dog vomit immediately might save its life. This means taking the dog to a vet as soon as possible. If this is not possible there are various last resort methods of inducing vomiting such as drenching with a supersaturated (very strong) solution of household salt in warm water, or making the dog swallow a crystal of washing soda (sodium carbonate). Caustic soda (sodium hydroxide) must not be used.