WO1997019598A1 - Method for controlling ammonia, arthropod infestation and reducing animal stress in confined room animal husbandry - Google Patents

Abstract

The present invention relates to a method of treating an ammonia- and/or arthropod population-containing environment comprising applying to a surface or substrate in contact with the environment a non-toxic, thiosulfate-salt-containing composition in an amount effective to reduce ammonia and/or the arthropod population, to thiosulfate-containing compositions and to animal litter containing said compositions.

Description

METHOD FOR CONTROLLING AMMONIA. ARTHROPOD INFESTATION AND REDUCING ANIMAL STRESS IN CONFTNED ROOM ANIMAL HUSBANDRY

The present invention relates to a method of treating an ammonia- anαVor arthropod population-containing environment, comprising applying to a surface or substrate in contact with the environment, a thiosulfate-containing composition. The method can be used to reduce the concentration of ammonia in an ammonia-containing environment, to reduce the arthropod population in an arthropod population-containing environment and/or to reduce stress of an animal in an ammonia- and/or arthropod-containing environment. The present invention also relates to compositions comprising thiosulfate, elemental sulfur, and optionally sulfur-oxidizing bacteria, and to the use of said compositions, particularly in the reduction of the concentration of ammonia, pH, animal stress and arthropod infestation in an environment. In addition, the present invention relates to animal litter comprising a thiosulfate- and, optionally elemental sulfur-, containing composition.

Physiologically toxic or unpleasant malodors occur widely in the living environment of man, for example, in the production, processing, repacking, filling, storing, freshness- retaining, transportation, discarding, etc. of various products common to the industries of agriculture, farming, forestry, animal husbandry, and fishing. Typically, sulfur- and nitrogen-containing compounds are responsible for such malodors, and effective treatments are still being sought.

Among such malodorous compounds, urea or uric acid are excreted by animals as a result of normal metabolism and are rapidly converted into ammonia by biological action, primarily bacterial action. In aquatic systems, fish and other aquatic animal life excrete urea directly into the water, where it is rapidly converted into ammonia. Non-aquatic animals, including humans, also excrete urea into natural habitats and, in the particular case of domestic animals and livestock, into artificial habitats, such as stalls, coops, cages, litter pans and other indoor- and outdoor-housing structures. Ammonia is also produced as a result of the decay of solid animal waste and uneaten food, or undigested food in fecal matter.

At room temperature, ammonia is a gaseous environmental contaminant which has an undesirable pungent odor. In concentrated animal populations typically found in commercial animal production units common to hog and poultry, such as chicken (Gallus domesticus). turkey (Meleagris gallopavo). ducks (Anas platyrhynchos). gease (Anser spp.), Coturnix quail (Cortunix cortunix or C. Cortunix iaponica). bobwhite quail (Colinus virginianus), chukar partridge (Alectors chukar), pheasants (Phasianus colchicus) and guineas, guinea hens or guinea fowl (Phasianus colchicus), production, ammonia accumulations exert severe physiological stress on the animal population. In poultry production, for example, ammonia concentrations typically found in confined growing conditions cause stress symptoms such as respiratory distress, increased susceptibility to bacterial infection, decreased weight gain, blindness and in severe cases mortality. These effects are significant, and in addition to causing sickness or death to the distressed animal, cause economic loss to the grower. Many strategies have been employed to reduce the above mentioned ammonia-related confined growth stress or mortality effects, e.g., in poultry flocks. For example F.N. Reece et al., "Ammonia in the Atmosphere during Brooding Affects Performance of Broiler Chicken", Poultry Science. 59, pages 486 - 488, 1980, discloses a study in which the weight gain of broiler chickens exposed to ammonia during the 0 - 28 day brooding period, was adversely affected.

A paper by H.A. Elliot and N.E. Collins entitled "Factors Affecting Ammonia Release in Broiler House", 1982, Transactions of the American Society of Agricultural Engineers, pages 413 - 424, discloses a computer program for modeling ammonia (NH₃) release in broiler houses. Of the factors studied in the Elliot and Collins paper, NH₃ volatilization was influenced, in order of importance, by: litter pH » temperature > moisture content. As explained in that paper, the nitrogenous end product of uric acid degradation is NH₃, which includes both the uncharged soluble NH₃ species, NH₃ (aq), and the ammonium ion, NH/. As further stated therein, because the equilibrium partial pressure of gaseous NH₃ in the litter (P_L) is large compared to the ambient NH₃ partial pressure in the house atmosphere (P_A), NH₃ will be transferred from the litter to the atmosphere. It is suggested in the paper that one of the most effective means of controlling NH₃ volatilization is to chemically treat litter with acids, for example phosphoric acid and volatile fatty acids, to maintain a low pH. In contrast to the litter treatment suggested by Elliot et al, namely treatment with an acidic chemical, an embodiment of the present invention (as hereinafter defined), treats a surface or substrate in contact with an ammonia- and/or arthropod population-containing environment, e.g., a chicken or turkey house with a thiosulfate-containing composition. Such a composition is non-acidic and accordingly does not suffer from the disadvantages discussed above. The present invention may be practiced in treating an environment used in the production of any of the abovementioned animals. Hereinafter, such an environment will be referred to as an animal environment. Two of the more important animal environments which may be treated according to the present invention are the domestic chicken- and turkey-environments. Chickens reared for meat are called broilers. Broiler house stocking densities typically range from about 1 1 to 16.5 birds/m² ( 1.0 to 1.5 birds/ft²), depending on weather, environmental conditions and the target market weight of the birds. Typical stocking densities in southeast USA range from about 13.2 to 14.3 birds/m² ( 1.2 - 1.3 birds/ft²) Stocking densities for turkeys vary, since the very young birds (poults) are grown in separate buildings for the first month. Poult brooder buildings are stocked at about 33 - 44 birds/m² (3-4 birds/ft²). Grow-out buildings are stocked at a lower density, typically about 22 - 33 birds/m² (2-3 birds/ft²) or less if it is desired to grow a large bird full grown 13 6 kg (301b) toms, may require 0 45 - 0.63 m²/bιrd (5-7 ft² bιrd)

Conventional methods for reducing ammonia and/or reducing stress in animal rearing, e g., the use of zeolites, have been unsuccessful Forced ventilation of the animal environment is most common, but has the drawbacks of excessive heating and power costs Chemical remedies, such as dilute mineral acids (e.g., phosphoric) have provided some relief, but they are corrosive, hazardous to the applicator, and require specialized equipment and tankage Other chemicals have been used, for example, alum, lime, aldehydes and ketones, essential oils, persulfates, ferrous sulfate heptahydrate, dlkanolammes, and sulfa drugs. Each has been found to have inherent drawbacks such as cost, irritancy, toxicity, corrosivity, or impractical dosage requirements

In addition, there are significant arthropod pest problems in modern integrated animal production The major arthropod pests found in modern high density PPf are: (a) ectoparasites mites, lice, and bedbugs, and (b) habitat pests darkling (litter) beetles and filth flies (house fly and other species) Integrated arthropod pest management programs must counter all of these pests The major arthropod pest species of concern and the pest management strategies vary with the animal, housing and production systems

The ecology of arthropod pests is tied to the artificial environment in which they and the animals exist, and changes in the environment which reduce arthropod populations can only be made if they are not detrimental to the animals Since the environments of the \ aπous types of production facilities differ, so too does the arthropod pest population as does the adverse effect on the animal host caused by the particular arthropod population The impact of arthropod ectoparasites on poultry, for example, involves the stressing of the bird, feeding on the bird, and/or vectoπng of disease organisms harmful to the bird Pests that are not ectoparasites may nevertheless lower the quality of the birds' environment and thereby also cause stress to the birds

Common ectoparasites that cause stress to poultry include the northern fowl mite, Ornithonyssus sylviarum, the chicken body louse, Menacanthus stramineus, the chicken mite, Dermanyssus gallinae, and the bedbug, Cimex lectularius In confined poultry housing, a diversity of insects and mites will be found in the accumulated poultry manure (in caged-layer houses and beneath the slats in breeder houses) and litter (feces mixed with wood shavings or other plant materials in broiler and turkey grow-out houses and portions of breeder houses) These arthropods are mainly species of beetles (Coleoptera), flies (Diptera), and mesostigmatid mites

Extremely large populations of all stages of habitat pests, such as beetles, can be found in some poultry houses, especially in the litter of broiler and turkey growout houses The beetles often aggregate in areas of higher temperature, suitable moisture (especially around waterers), and nutrients (mainly spilled chicken feed) Consequently, greater numbers of insects may be found under and around feeders and waterers in broiler and turkey growout houses, and in areas of spilled feed in accumulated manure under caged- layer hens

The two major pest species of litter beetles are Alphitobius diapermus (Tenebπonidae), the darkling beetle, and Dermestes maculatus (Dermestidae), the hide beetle The darkling beetles are both reservoirs and vectors for a wide variety of pathogens, including several that are threats to poultry production They harbor fungi (Aspergillus), bacteria (Escherichia, Salmonella, Bacillus, Streptococcus), and viruses causing leukosis (Marek's disease) and infectious bursitis (Gumboro disease) A variety of other viruses, including the agents causing fowlpox, Newcastle disease, and avian influenza, have also been recovered from the beetles Avian cocciodosis, a major disease of poultry caused by protozoans (Eimeria spp ) is a poor survivor in poultry litter but survives as oocysts ingested by beetles which may then be ingested by the birds The cysticercoids of helminths (Choanotaenia and Railhetina) which affect poultry have been recovered from A diapermus demonstrating its role as an intermediate host It has been suggested that the insect may cause lesions on the birds [Bergmann et al , Hautkarzinomatose bei Broilern, Monat Veteπnaermed , 4J_, pp 815- 17 ( 1986)], and the scratching activity of the birds seeking the beetles in the litter may increase the susceptibilities of the birds to disease agents, owing to the irritation of the respiratory tract from the resulting dust.

Attempts to reduce A. diaperinus in poultry houses have been, at most, only partially successful. Thorough cleaning of the houses followed by leaving them empty and unheated for a prolonged period in a cold climate will reduce the rate of beetle population increase in subsequent flocks, but these measures do not satisfactorily reduce the infestation. Application of insecticides to the structure (including the soil floor) after cleaning assists in lowering the beetle survival, but mixing insecticides with disinfectants is risky due to a loss of both germicidal and insecticidal effectiveness. A variety of organophosphate, carbamate, and synthetic pyrethroid insecticides and borates are toxic to the beetles as residues on the structure or in the litter, but although effective in laboratory tests, they yield only temporary arthropod population reductions in the poultry house. Likewise, insect growth regulators, juvenile hormone analogues, and avermectin and similar anti-parasitics have effects in laboratory tests but have not been demonstrated to be effective in the field.

In view of the deficiencies and inefficiencies of the prior art, it is desirable to have a method for reducing animal stress resulting from ammonia and/or arthropod pests that is safe, non-toxic to animals, including humans, easy to use, and is capable of keeping confined animal growth environments at reduced pH and substantially ammonia- and arthropod pest-free for an extended period of time.

The present invention also relates to thiosulfate-containing compositions, comprising elemental sulfur and, optionally sulfur-oxidizing bacteria.

The present invention is further directed to an animal litter comprising thiosulfate-, and optionally elemental sulfur-, containing compositions.

The present invention further provides a method of treating an ammonia- and/or arthropod population-containing environment, comprising applying to a surface or substrate in contact with the environment, a non-toxic or thiosulfate-containing composition in an amount effective to reduce the concentration of ammonia and/or arthropod population in the environment.

The ammonia may be both airborne and/or trapped in or on a surface or substrate in the environment, e.g., animal waste in the form of ammonium hydroxide (NH₄OH).

The method of the present invention is suitable for treating an ammonia- and/or arthropod population-containing environment such as closed and open environments which are naturally occurring or man-made including, but not limited to, animal litter, animal litter containers, cages, crates, stalls, coops, pens, houses, public toilets and other environments where ammonia and/or arthropod pests may be found

In accordance with the present invention, ammonia concentration and/or arthropod infestation-inducing stress, for example in fowl coops or swine pens, may be suφrisingly reduced by adding to the environment a thiosulfate-containing composition in an amount effective to reduce the ammonia concentration and/or arthropod infestation in the environment Such a treatment has been discovered to reduce stress (which can be measured by mortality or weight gain), decrease airborne ammonia concentrations and decrease in arthropod pest infestation in animals grown in confined or crowded conditions Observed benefits include better food utilization resulting in increased weight gain and thus increased production, in addition to reductions in deleterious bacteria in the litter, reduction of animal eye irritation and blindness, reduced animal buccal and/or tracheal irritation, greater viability of animal populations, and generally, better overall health

It will be understood by one skilled in the art, that the method of the present invention may be used on its own or in combination with any other method known for reducing the ammonia concentration of an ammonia-containing environment, with the proviso that said other method is practical with respect to considerations such as toxicity, irritancy, dosage requirement and corrosivity Thus, for example, the method of the present invention may be used in summer, in combination with ventilation means, whereby ventilation cools the environment and reduces the airborne ammonia concentration

Accordingly, in a further embodiment of the invention, there is provided a method of reducing stress of an animal confined in an ammonia- and/or arthropod-population- containing environment comprising applying to a surface or substrate in contact with the environment a non-toxic, thiosulfate-containing composition in an amount effective to reduce stress, wherein the stress reduction is determined by a reduction in animal mortality and/or an increase in animal weight gain relative to the mortality and/or weight gain observed in an animal housed in the same environment to which no thiosulfate-salt- containing composition has been applied.

By the term ' same environment" is meant an environment which is the same or substantially the same with respect to temperature, density of animals, and diet regimen administered to the animals

The increase of weight gain will be dependent on the particular animal species, the period over which the weight gain is measured, the stage of development of the animal and the diet administered. Both significant weight increases and decreases in mortality rate have been observed in the practice of the present invention.

The thiosulfate compounds used in accordance with any one of the embodiments of the present invention are non-irritating and non-toxic to animals, including humans, and non-corrosive. Preferred thiosulfate-containing compositions are thiosulfate salts, and include alkali metals, such as sodium and potassium, and alkaline earth metals, such as calcium and magnesium. A particularly preferred thiosulfate-salt-containing composition is a composition comprising sodium thiosulfate. Such thiosulfate-salt-containing compounds are commercially available (e.g., from PVS, General Chemical or Calabrian) and are often used in photography, scale prevention, dechlorination and mining. Sodium thiosulfate, in fact, has been used as a food additive for chicken rations and may even be sourced from the waste liquor of sulfur dye manufacture. Thus, the ease of handling and mild nature of the chemical compounds useful in the present invention represents a significant advance in protecting workers, animals, and equipment, while providing efficient reduction of airborne ammonia, arthropod pests and animal stress in confined growth animal husbandry environments.

The amount of the thiosulfate-containing composition effective to reduce the ammonia and/or the arthropod pest population and/or animal stress, will vary depending on the concentration of ammonia and/or size of the arthropod population present in the environment, and method of application of the thiosulfate-salt-containing composition to the environment. The thiosulfate-salt-containing composition is suitably introduced as a spray directed downward towards the litter at greater than 100 ppm, typically greater than 10,000 ppm. In other words, the thiosulfate-salt-containing composition may be applied at a dose of between about 0.048 to 9.764 Kg/m² (0.01 to 2 lbs./ft.²) of treatment target area, preferably at about 0.15 to 8.544 kg/m² (0.03 to 1.75/ft.² ) most preferably 0.244 to 7.32 kg/m² (0.05 to 1.5 lbs/ft²). Typically, the composition is introduced as an aqueous spray. The composition may also be applied to the bedding area, e.g., to the litter, and adjusted as necessary to reduce the concentration of airborne ammonia in the environment, the arthropod pest population and to lower the pH of the moisture present in the litter. By lowering the pH of the moisture of the target area, the stability of the association between water and ammonia, which together form, NH₄OH, is increased. Accordingly NH₄OH is less likely to dissociate into ammonia and water. Thus, the concentration of ammonia formed by dissociation is reduced and, accordingly, less ammonia escapes into the atmosphere of the environment A discussion on the effect of litter pH and the volatilization of NH₃ is presented in H.A. Elliot et al. in the paragraph bridging pages 415 and 416, the contents of which being hereby incoφorated For convenience, the effect caused by the thiosulfate-containing composition may conveniently be referred to as ammonia fixing Accordingly, references hereinabove to a reduction in the concentration of ammonia, are to be understood in the sense that the concentration of ammonia in the atmosphere of the environment is less than the amount which would otherwise be present in the atmosphere of the environment in the absence of application of the thiosulfate- containing composition of the present invention or alternatively expressed, the ammonia is being fixed

As used hereinabove, by an effective amount of thiosulfate-containing composition in relation to the embodiment of the invention dealing with reducing stress of an animal, is meant an amount to reduce animal mortality and/or to cause an increase in animal weight gain relative to the mortality and/or weight gain observed in an animal housed in the same environment to which no thiosulfate-containing composition has been applied

The pH of litter on which confined growth poultry and other animals reside, when treated according to the process of the present invention, decreases up to 2 or more pH units Untreated, the litter typically reaches pH levels in excess of 8 where bacteria flourish Low pH has been shown to decrease the number of deleterious and pathogenic bacteria, thus decreasing the overall stress on the flock or herd Salmonella, particularly, are beneficially reduced by low pH such that incidence of Salmonella contamination is decreased at slaughter This effect is of benefit to processors for whom reduction or control of Salmonella contamination, e g., in chicken products, is of great importance

The process of the present invention also provides environmental conditions within the pen, coop, bedding, litter, etc which, in addition to reducing the concentration of ammonia, reduce, discourage, inhibit and/or eliminate the infestation of arthropods and/or parasites commonly found in such areas, including darkling beetles Hereinafter, the term control" or "arthropod control" will be used generically with respect to application of the thiosulfate-containing composition to reduce, discourage, inhibit and/or eliminate the infestation of arthropods and/or parasites in an ammonia- and/or arthropod population- containing environment treated according to the process of the present invention

In an effort to obtain moisture in a confined growth poulty house, darkling beetles in search of moisture have occasion to bite poultry when they sit down to rest Such bites may create skin irritation and a concomitant opening for bacterial infections such as gangrenous dermatitis. In addition, poultry may have occasion to feed on the beetle, whether larvae or adult, in which pathogenic agents reside. The so-infected adults and larvae tend to aggregate so that large numbers will be found in certain areas in the poultry litter or manure. They will accumulate under boards, feeders, or waterers set on the litter. Beetle adults and larvae often aggregate under dead or dying birds on the litter to feed on the carcasses. Accordingly, the instant process enables the control of such beetles, parasites and pests, as pathogenic vectors. An indirect approach to measuring the beetle population, in order to determine the effective arthropod control application dose or rate, is using a "tube trap". This trap is a 10 in. long piece of 1.5 in. diameter PVC pipe with an insert of rolled corrugated cardboard (such as used for brooder guard). Holes near the end of the pipe allow staking with gutter nails to prevent the birds from moving the tube. After the tube trap is on the litter for one week, the cardboard insert is removed and the beetles (larvae and adults) counted. A new cardboard insert should be used each week. At least 10 of these traps should be used per house. The effective rate of application of the thiosulfate- containing composition to control the arthropod pests may be routinely adjusted according to the size and vitality of the arthropod population to be treated in accordance with known methods.

Another embodiment of the invention provides a process of treating animal or fowl bedding or litter material with an amount of thiosulfate-containing composition effective to achieve and maintain the animal or fowl bedding or litter at a pH of less than 7.5, preferably between 4 and 7, most preferably between 5 and 6.5. The thus treated animal or fowl bedding or litter can be used in a confined environment or holding tank for animals or fowl.

The animal or fowl bedding or litter material can be organic waste material, for example, straw, such as wheat, barley, oats, rice, stover, such as corn and milo, cotton waste, grape pomice, vegetable wastes, wood shavings, sawdust, bagasse, peanut hulls, peat tobacco stems, cocoa shells, rice hulls, or any other waste organic material. The preferred animal or fowl bedding or litter material is sawdust or some other adsorbent material onto which the thiosulfate-containing composition has been applied.

In a preferred embodiment, an aqueous sodium thiosulfate-containing solution may be compounded with emulsified elemental sulfur. Surfactants, dispersants, and thickening agents may also be used, along with a small particle-size (preferably 5 microns or less) form of elemental sulfur in order to produce a stable suspension of up to 15%, preferably between 8.0% and 12%, by weight sulfur in the final composition, preferably in a dispersion, that is suitable for application by standard agricultural spray equipment. The small size of the sulfur particles, and the presence of one or more conventional surfactants in the dispersion, aids in dispersing the sulfur and promotes the efficient utilization of the mixture by the sulfur-oxidizing bacteria. Alternatively, the elemental sulfur may be introduced at a concentration of about 0.005 to 5 kg/m² (0.001 to 1 lb/ft²), preferably 0.025 to 2.5 kg/m² (0.005 to 0.5 lb/ft²), most preferably 0.05 to 1.25 kg/m² (0.01 to 0.25 lg/ft²), either together with, in sequence with, or independently from, the thiosulfate-containing composition.

The unexpected advantage of using elemental sulfur in the compositions of the invention is that the same group of microorganisms that convert thiosulfate to sulfate also oxidize elemental sulfur to sulfate. Although the biological process is slower, a given weight of sulfur will generate a greater amount of acid than thiosulfate. Accordingly, treatment with the elemental sulfur alone (i.e., in the absence of a thiosulfate-containing composition), e.g., up to 72%, preferably 10-25%, by weight in an aqueous dispersion thereof, also provides the bacteria with an effective pH reducing species to effect the described ammonia fixing reaction.

The mixture of thiosulfate and sulfur is in effect a two-stage product, wherein the thiosulfate reacts quickly to reduce the airborne ammonia, and the elemental sulfur provides the necessary acidity over a longer period of time. The application of such a mixture can reduce the pH of litter in confined growth poultry houses by up to 3 pH units or more. The aqueous thiosulfate composition stimulates the population of sulfur oxidizing bacteria so that utilization of the elemental sulfur begins promptly. Such a mixture is also unexpectedly effective in reducing arthropod pests.

Thiosulfate is a preferred substrate to provide immediately available metabolic energy to sulfur-oxidizing bacteria. However, sulfur-containing anions, e.g., sulfite, and bisulfite and metabisulfite individually or together, may also be used in a formulation with other substrates to form multi-stage products to provide energy for the bacteria. Accordingly, for the puφoses of the present invention, it is to be understood that any reference herein to thiosulfate may be replaced by sulfite, metabisulfite, or bisulfite, unless the context indicates otherwise. A further embodiment of the invention is to supplement the thiosulfate and/or sulfur application (especially the application of a liquor or aqueous dispersion thereof) with the concurrent and/or consecutive application of an effective pH reducing amount of sulfur oxidizing bacteria, such as Thiobacύlus thwoxidans As a result of this supplemental application, the thiosulfate is biologically oxidized in situ by bacteria, an active acidic species being produced in the litter thereby decreasing the pH of the litter In a preferred embodiment, an enrichment culture of sulfur oxidizing bacteria is applied in the form of an inoculum By the term enrichment culture, is meant a culture of selected bacteria isolated from particular environments, e g , litter from poultry houses, by a technique of supplying specialized substrates, thus encouraging the relative abundance of those bacteria best able to utilize the substrate A concentrate can be made of such enrichment, which concentrate is stable for storage and transportation The concentrate can be recultured to make a large- volume preparation of the desired bacteria, ready for addition to a similar environment from which the original enrichment was recovered Such cultures are typically used in microbiological applications, to supplement a pre-existing bacterial population These enrichment cultures are made according to known methods, and do not carry a great risk of deleterious or pathogenic bacteria Since many growers disinfect or carry out procedures designed to reduce the numbers of all bacteria prior to introducing a new flock of birds to the pen, cage, or other growing area, the population of sulfur-oxidizing bacteria may likewise be reduced Use of an enrichment culture in the method of the present invention, ensures that the appropriate bacterial oxidation of the thiosulfate or the elemental sulfur, or the thiosulfate and the elemental sulfur takes place in situ so that the litter pH is indeed lowered and the concomitant benefit of ammonia-stress reduction and arthropod population reduction is reliably obtained, in particular in those circumstances, wherein the population of sulfur oxidizing bacteria is low It is therefore contemplated that the use of a dispersion of small, dispersible particles of elemental sulfur together with a "seed population" of sulfur oxidizing bacteria can be effective to reduce the pH in litter and alleviate physiological stress due to airborne ammonia and arthropod pests It should be appreciated that the use of an enrichment culture of bacteria as hereinabove described, is an optional feature of the process of the present invention

In yet another embodiment of the invention, alkaline earth metals, such as calcium, may be substituted for sodium (or potassium) in the thiosulfate-containing composition or solution used in the invention Such divalent cations interact with soluble phosphate to form salts which have reduced solubility Accordingly, when used litter containing alkaline earth metals is spread on fields to realize its fertilizer value, a lesser amount of soluble phosphate escapes to local waterways duπng precipitation Thus, reducing phosphate solubility retains fertilizer value on the field as well as reducing the degradation of water quality in adjacent water bodies

In yet another embodiment of the invention, dyes or colorants, or both, may be added to the active thiosulfate-contammg composition or solution so that the applicator can easily visualize the location of the active mateπal on the substrate, e g , litter, to ensure total substrate coverage

The thiosulfate-containing composition of the invention may contain other additives, such as dispersants, surfactants, perfumes, coloring agents, adsorbents, etc , which do not adversely affect the stress- or ammonia concentration-reducing properties of the thiosulfate or thiosulfate/sulfur mixture

In some cases, due to the high level of ventilation of the environment to which the thiosulfate-containing composition of the present invention is added, the environment will be free or substantially free of ammonia Where the environment comprises ammonia, the ammonia concentration will be at or below the level generally causing stress to the animal species, ι e , ιt will be at a level hereinafter referred to as a non-stress-causing ammonia concentration It has been observed that the compositions of the present invention also reduce the stress of animals confined in such environments, the stress reduction being indicated by a lower rate of mortality or a higher average body weight of the animals compared to control animals In such environments the stress is as a result of non-ammonia factors, e g , the presence of an arthropod population

Accordingly, in a further embodiment of the present invention there is provided a method of reducing stress of an animal confined in an environment in which the ammonia is at a non-stress-causing concentration comprising applying to a surface or substrate in contact with the environment a non-toxic, thiosulfate-salt-containing composition in an amount effective to reduce stress, wherein the stress reduction is determined by a reduction in animal mortality and or an increase in animal weight gain relative to the mortality and/or weight gain observed in an animal housed in the same environment to which no thiosulfate-salt-containing composition has been applied

It will be understood from the foregoing that the thiosulfate-containing composition may be added to an environment which is free or substantially free of ammonia, to an environment containing ammonia; or it may be added to an environment which will contain ammonia at a future date. Similarly the thiosulfate-containing composition may be added to an environment which has little or no arthropod population, already contains an arthropod population, or an environment which will contain such a population at a future date.

Accordingly, references hereinabove to an ammonia-containing environment are to be understood as encompassing environments which it is anticipated will, at some time contain ammonia. Similarly, references herein to an arthropod population-containing environment, encompass environments which, at some time will contain such a population.

Where the thiosulfate-salt-containing composition is added to an environment which it is anticipated will contain ammonia and/or an arthropod population, an effective amount of thiosulfate-salt-containing composition, is an amount sufficient to reduce the estimated or anticipated amount of ammonia, and/or to control the infestation of arthropod pests in the environment and/or in an amount to lower pH.

In a preferred embodiment of the present invention, the thiosulfate-salt-containing composition is in the form of an aqueous solution. Such aqueous solutions are typically 10-50% by weight, preferably 20-40%, most preferably 25-30% thiosulfate by weight based on the weight of the solution. Solutions may have a lower concentration of thiosulfate by weight, however, and still produce a measurable beneficial effect. Solutions of greater than 50%, e.g., up to 95 % or higher, though obviously effective, are believed to be unnecessary. Generally, the compositions of the present invention are added to the environment to be treated, as a dilute aqueous solution, for example, by being sprayed onto a surface or substrate in contact with the environment, e.g., animal litter. After drying, the resulting thiosulfate crystals are very small and the physicochemical mixing and the microbial oxidation proceed immediately, albeit at different rates.

The crystalline or non-biologically mediated interaction between the thiosulfate and ammonia, when present, depends on mixing and contact with the ammonia gas. The biologically-mediated oxidation of the thiosulfate depends on the relative numbers of sulfur-oxidizing bacteria. Many variations of application may be used in order to produce a prompt effect. In a preferred use, litter is treated before each new poultry flock is introduced into the environment. In commercial broiler houses, a single application is sufficient to carry the flock through about 40 days of reduced ammonia concentration and/or reduced pH and/or reduced stress and/or reduced arthropod population. The thiosulfate-containing composition may be applied directly to the environment, e.g., to an environmental surface or into environmental substrates (e.g., animal litters, latrines, earth, etc.) by any suitable method, for example, by spraying or by applying with a brush or mop. Alternatively, the surface or substrate may be manufactured with the thiosulfate-containing composition in association therewith, e.g., cage board.

It is presently preferred to apply the active solution to the environment in an amount sufficient to wet or coat the area with the solution until the portion of the environment contacted with the active solution is damp. The environment need not be soaked or saturated with the thiosulfate-containing active solution.

One skilled in the art will readily understand, in view of this disclosure, that the amount of active solution or crystals necessary to treat an ammonia- and/or arthropod population-containing environment, will depend upon the size of the area to be treated, the method of application, the composition of the substrate (such as litter, bedding, hard wood, tile, concrete, or caφeted floors, or walls, or ceilings or other components of structures, clay, metal, cage board, zeolite, etc.), to be contacted with the thiosulfate-containing composition, the amount and rate of ammonia production estimated or anticipated in the environment, the concentration of the active solution and the ammonia-controlling capacity of the thiosulfate-containing composition used, the arthropod population, among other factors. For example, where the thiosulfate-salt-containing composition is added to animal litter, such as sawdust, the high surface area and high adsoφtivity of the sawdust generally requires a relatively larger amount of the composition togetherwith mixing of the litter to fully cover or coat the available surface area of the litter.

In the broadest aspect of the present invention, the thiosulfate and/or thiosulfate- sulfur treatment may be effectively used in portable latrines or bathrooms, such as are commonly found in public places, e.g., at parades, concerts, sporting events, and the like, where many people gather. Many other variations and uses of this invention will occur to those of skill in the art in light of the above, detailed description. All such obvious variations are within the full intended scope of the appended claims.

The present invention will now be illustrated by the following examples, it being understood that the examples are non-limiting. Example 1

A method of treating an ammonia-containing environment in which the ammonia concentration is at a non-stress-causing concentration due to the presence of strong ventilation, the study being carried out during warm weather (³ 20°C)

Method

Twelve 4 x 12 ft chicken pens are used Six pens are control pens, to which no thiosulfate- containing composition is applied and six are test pens to which thiosulfate composition is applied The thiosulfate-containing composition is applied in a concentration of 0 244 kg/m² (0 05 lbs /ft²) of sodium thiosulfate and 0.058 kg/m² (0 012 lbs./ft²) of elemental sulfur to the litter in each pen The litter used is one flock old pine chips Optional brooding conditions (temperature/humιdιty)are maintained for 24 days The chickens receive the same food mixture The total amount of feed given to the chickens in the four test pens is 240 3 kg (529 8 lbs), the total amount given to the chickens in the control pens is 238 7 kg (526 4 lbs ) The total weight of the test chickens is 216 7 kg (477 7 lbs), and that o the control chickens is 21 1 0 kg (465 2 lbs)

Results

Food conversion Average bird Mortality (%) (kg feed/kg live weight (kg) weight)

Test 1 109 0.929 2 9

Control 1 32 0 916 4 2

Example 2

A method of treating an ammonia-containing environment (a broiler house) in which the ammonia concentration is at a stress causing level Each broiler house measures about 12 x 150 m (fourty x 500 ft ) The ventilation in all houses is at the same level Method

Study 1 (control)

Four broiler houses as above described, the total number of birds in each house is 24,500

The birds are monitored over a 42 day period. The houses had only been used once before

Study 2 (test)

After completion of study 1 , above the above four broiler houses were re-used for a repeat of study 1 , except that in the case of this study, a sodium thiosulfate- and elemental sulfur- composition according to the present invention is used to spray the litter prior to placing the birds in the houses.

Results

No of dead birds No. of dead birds No. of dead birds week 1 (%) week 2 (%) week 3 (%) study 1 759 (0.77 %) 660 (0.678 %) 347 (0.359 %) study 2 232 (0.236 %) 281 (0.287) 267 (0.273 %)

A measure of the pH in the litter in the houses of study 2 is presented in figure 1. From this figure it can be seen that the pH decreases dramatically to below 6.5 in the presence of the thiosulfate-containing composition of the present invention. In the absence of the composition of the present invention, the pH of the litter is at about 8.5

Claims

1 A method of treating an ammonia- and/or arthropod population-containing environment comprising applying to a surface or substrate in contact with the environment a non-toxic, thiosulfate-containing composition in an amount effective to reduce ammonia and/or the arthropod population

2 A method as claimed in claim 1, wherein the environment is selected from the list of animal litter, animal litter containers, cages, crates, stalls, coops, pens, houses, public toilets and other environments where ammonia and/or arthropod pests may be found

3 A method as claimed in either claim 1 or 2 wherein the environment is a chicken or turkey house

4 A method of reducing stress of an animal confined in an ammonia- and/or arthropod population-containing environment comprising applying to a surface or substrate in contact with the environment a non-toxic, thiosulfate-containmg composition in an amount effective to reduce stress, wherein the stress reduction is determined by a reduction in animal mortality and/or an increase in animal weight gain relative to the mortality and/or weight gain observed in an animal housed in the same environment to which no thiosulfate-salt-containing composition has been applied

5 A method as claimed in claim 4, wherein the ammonia concentration in the environment is at a non-stress-causing concentration

6 A method for reducing stress of a confinement-reared, non-human animal which comprises treating the bedding or litter of the animal with an effective amount of a thiosulfate-containing composition mixed with up to 10% by weight emulsified elemental sulfur based on the weight of the mixture to reduce the pH of the bedding or litter of the animal to less than 7.5

A method as claimed in any one or claims 1 to 6, wherein the thiosulfate-containmg composition is a salt

The method as claimed in claim 7 wherein the salt is an alkali metal thiosulfate- or alkaline earth metal thiosulfate-salt-containing composition.

A method for reducing stress of an animal in a confined growth, ammonia- contaimng, environment, comprising applying to a surface or substrate in contact with the environment a non-toxic, alkali metal or alkaline earth metal thiosulfate- containmg composition in an amount effective to reduce animal stress in the environment

A method as claimed in any one of claims 1 to 9, wherein the thiosulfate-salt- containing composition is added in an amount in the range of 0 048 to 9 764 kg/m²

A method for reducing or eliminating the infestation of arthropod pests in a confined growth, animal containing environment comprising applying to a surface or a substrate in contact with the environment thiosulfate-salt-containing composition in an amount effective to reduce or eliminate the arthropod pests in the environment

A method as claimed in claim 1 1 , wherein the thiosulfate-salt-containing- composition is a sodium thiosulfate-containing composition

A method as claimed in any one of the preceding claims wherein the substrate comprises litter

A method as claimed in any one of the preceding claims wherein the thiosulfate-salt- containing composition is in the form of an aqueous solution

A thiosulfate-salt-containing composition comprising an alkali metal thiosulfate- or earth alkali metal thiosulfate-containing composition and elemental sulfur

16. Use of a thiosulfate-salt-containing composition as claimed in claim 14 in a method as claimed in any one of claims 1 to 13 above.

17. Litter material to which a thiosulfate-containing composition has been applied.