NZ537368A - Bait for control of animal pests, comprising a vitamin D sterol and a calcium compound - Google Patents

Abstract

Disclosed is a bait for control of animal pests, containing an ingestible base material, and including 0.4% to 1.25% by mass of a vitamin D sterol, and calcium compound within the range 0.25% to 3.0% by mass, selected from a calcium phosphate or calcium sodium lactate, or mixtures of a calcium phosphate and a calcium sodium lactate, and wherein the calcium sodium lactate may be replaced directly with calcium potassium lactate. (61) Addition to 329006

Description

New Zealand Paient Spedficaiion for Paient Number 537368 Patents Form No.5 NEW ZEALAND 53 7 3 6 PAT.5 PATENTS ACT 1953.

COMPLETE SPECIFICATION.

MANAGEMENT OF VERTEBRATE PESTS.

I ERIC RAYMOND WEAVER, of 24 Umere Crescent, Ellerslie, Auckland, New Zealand, a New Zealand Citizen, Hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to pest control and has been devised particularly to provide improved toxic bait for the control of vertebrate animal pests.

Experience in New Zealand and elsewhere has been that many introduced animal species eventually create an imbalance in ecosystems and become pests, due mainly to their predator activity on indigenous animals and destruction of habitat and ecosystems. In fact, as long ago as 1872 the British scientific journal "Nature" recognised the problem and published the following warning: "In a reckless way, the animals of extremely doubtful advantage have been transported to the Antipodes and unaccompanied by any of those checks which keep natural fauna balanced, the importations will inevitably become the greatest of nuisances." It seems surprising that the functioning of ecosystems and the need for balance was of concern so long ago and yet it is only recently, when the adverse effects have become so obvious that belated efforts are being made to control and remove introduced animals which have become very serious pests. Even the Australian possum which was until recently thought to be vegetarian has now been found to feed on birds eggs and small animals. The problem is compounded by a desire to control and remove the pests in a humane way, and without causing undue harm to non-target species and the environment. Toxins are employed in the form of bait, either ground laid or aerially sown in the area to be treated. The carrier substance for the toxin may be a fruit or essence containing paste or solid cereal pellet, or diced rootcrop such as carrot for example, or other forms of ingestable material to which a suitable toxic substance or mixture has been added. To reduce the incidence of the bait being taken by non-target species it is usually dyed green, and when ground laid it is often isolated in self feeding bait stations which present the bait to the target species and have the advantage of protecting the bait from the weather. Various aromatic substances are often added to the bait to render it more selective or attractive.

The most cost effective toxin used in New Zealand at present for control of possums and rabbits is probably 1080, the common name for sodium fluoroacetate. The use of this substance is currently being reviewed. Sodium or potassium cyanide, is also used, and while it is particularly humane in its action pests can become strongly bait shy from sublethal doses. Being a potent acute toxin, the use of cyanide is strictly controlled. Secondary poisoning of animals feeding on the carcasses of pests which have taken some toxic baits can be either a problem or a benefit, depending on the animal species that succumbs to the secondary poison.

Anticoagulant toxins are also used. These have the advantage that they are relatively safe when used with reasonable care and this is recognised by making them readily available to the public. However, they have disadvantages of higher cost and a need to "pulse" the bait supply to avoid waste. Pulsing is the term used for intermittent feeding which avoids continued consumption of bait by animals which have already taken a lethal feed. We have found pulsing to be essential to avoid waste, as compared with continuous feeding it results in a reduction in bait consumption of about 60%. However, the savings due to reduced consumption are largely offset by the significant increase in labour required to service the bait stations, especially in rugged terrain. Some anticoagulants have a long persistence in animals and the environment which can cause concern, for both the health of non-target species and possible contamination of the human food chain.

It has been known for many years that vitamin D (of which there are at least ten active sterols), regulates absorption and utilisation of calcium and phosphorous in animals. This fact has been employed beneficially in formulating dietary supplement calcium tablets for example for the treatment of calcium deficiency in humans and other vertebrates.

More recently a new pest control bait has been disclosed and claimed in New Zealand patent Number 329006 wherein an ingestable base material including for example dried fruit, fish meal, milled cereal grain, or milled grain residues, contain a synergistic mixture including 0.4% to 1.25% by mass of a vitamin D sterol, and calcium compound within the range 3.0% to 60% by mass, selected from a calcium phosphate or calcium sodium lactate, or mixtures of a calcium phosphate and calcium sodium lactate, and wherein the calcium sodium lactate may be replaced directly with calcium potassium lactate, the materials being expressed as percent of the dry mass of the ingestable base material. The new pest control bait causes death by cardiac arrest following the onset of severe "calcinosis" and "phosphorosis" enhanced by the absorption and utilisation function of the vitamin D sterol. The bait offers advantages of availability without a license and death from ingestion of a single feed, and also has the considerable advantage of not introducing foreign substances to the environment.

Claims (2)

There are a number of difficulties with the types of bait presently available, either in terms of their restricted availability and use, deterioration under the ambient conditions often encountered in normal use, or their potential to contaminate the environment or human food chain. There is therefore a need for improved baits which eliminate or minimise some of the disadvantages of prior art baits. The bait is described in New Zealand Patent No 329006, goes a very considerable way in meeting the need for improved bait and the present invention describes further improvements to this bait wherein the quantity of active materials may be reduced to commercial advantage while still retaining useful toxicity. It is an object of this invention to provide improved bait for control of animal pests. It is a further object of this invention to provide bait for control of animal pests, which overcomes or minimises some of the disadvantages of prior art bait, or at least provides the public with a useful choice. According to one aspect of this invention there is provided improved bait for control of animal pests said bait including an ingestable base material, and including the following active materials expressed as percent of the dry mass of the ingestable base material: Vitamin D sterol 0.2% to 1.25% Calcium compound within the range 0.25% to 3.0%, selected from a calcium phosphate, a calcium sodium lactate, or mixtures of a calcium phosphate and a calcium sodium lactate. As is known in prior art potassium may be substituted for sodium in the calcium sodium lactate and this does not compromise functionality in the present invention. We have now found that the efficacy of the improved bait claimed in New Zealand patent number 329006 is fully confirmed and that the useful toxic efficacy is surprisingly good and extends below the lower limit of 3.0% by mass disclosed and claimed in New Zealand patent number 329006 for the calcium compound selected from a calcium phosphate, a calcium sodium lactate, or mixtures of a calcium phosphate and a calcium sodium lactate. Accordingly the present invention discloses an improvement in the form of a new lower limit which has been found effective for the calcium compound selected from a calcium phosphate, a calcium sodium lactate, or mixtures of a calcium phosphate and a calcium sodium lactate, for which we claim a patent of addition to New Zealand patent number 329006. In other respects the specification and claims of New Zealand patent number 329006 are unaffected and apply. The invention has been described by way of example only, and obviously known equivalent materials and components will be apparent to those skilled in the art, and these are included as if all were individually recorded in the description of the invention. WHAT I CLAIM IS:

1. Bait for control of animal pests containing an ingestable base material, and including 0.4% to 1.25% by mass of a vitamin D sterol, and calcium compound within the range 0.25% to 3.0% by mass, selected from a calcium phosphate or calcium sodium lactate, or mixtures of a calcium phosphate and a calcium sodium lactate, and wherein said calcium sodium lactate may be replaced directly with calcium potassium lactate, the materials being expressed as percent of the dry mass of the ingestable base material.

2. Bait as claimed in Claim 1, wherein the vitamin D sterol is vitamin D3, known in the art as cholecalciferol. ERIC RAYMOND WEAVER 4