GB2095970A - Dry and semi-moist pet food formulations containing rumen contents from ruminant animals - Google Patents

Abstract

Dry and semi-moist pet foods contain rumen contents from ruminant animals. The foods may also contain tripe from a ruminant animal and may be prepared by cooking-extrusion procedures. The pet food includes between 0.5% and 50% by weight rumen contents from a ruminant animal with a moisture content of the pet food not exceeding 35% by weight.

Description

SPECIFICATION Dry and semi-moist pet food formulations containing rumen contents from ruminant animals Background of the invention This invention relates to new and useful improvements in extruded pet foods containing material obtained from the rumen of a ruminant animal and to process for their preparation.

It is known that under natural conditions in the wild, Canidae and other families of the order Carnivora, such as wild dogs (Canis familiaris), wolves (C. lupus), hyaena (Crocuta crocuta, Hyaena hyaena, H.

brunnea), and the like commonly commence eating their kill, when said kill is a so-called ruminant animal, by devouring that part of the alimentary tract known as the rumen, and the contents thereof. Though the rumen contents are typically of lower nutritional value than other pants of the carcass, it has been speculated that they contain factors essential to the continuing health of canine predators and that the process of evolution has resulted in the organoleptic properties of such rumen contents becoming particularly attractive to the canine predator. ("Alles over honden", F.J. van Kleef-Mulder, Bogena, Waalwijk, 8de Druk, blz. 27. "The breeding and rearing of dogs" R.H. Smythe, Popular Dogs Publishing Co. Ltd., London, 2nd impression, 1972, pps 90-92).

The upper alimentary tract of the ruminant animal consists of a number of distinct anatomical divisions.

Ingested food travels via the oesophagus to an organ commonly known as the stomach, which in the ruminant animal consists of four compartments, namely the reticulum, rumen, omasum and abomasum, the first two compartments often being considered together as the recticulo-remen, which comprises about 85% of the total stomach capacity in adult animals. This invention relates to the material (of both ingested and endogenous origin) found in the recticulum, rumen and omasum and for the purposes of this invention, this material is hereinafter referred to as rumen contents. The compositon of this material reflects that of the ration consumed by the animal to some extent, but it is considerably modified by the metabolic activities of bacteria and protozoa, present in numbers of about 1010 ml-l and 106 ml-l respectively.These micro-organisms also contribute to the nutritional qualities of the rumen contents.

The organoleptic attraction of this material for dogs is acknowledged, and minced or ground whole rumen from cattle or other ruminant species is frequently used to supplement the ration of dogs, cats and other carnivorous pets in many countries, the said material being supplied either raw (stored in the frozen state), or cooked in the form of sausages or canned moist foods. In the latter cases, it is usual, though not mandatory, to add cereals (either whole or milled to a suitable consistency), legumes, other meat products (such as meat and bone meal, etc.), vitamins and minerals, in order that the overall composition may match the known nutritional requirements of domestic pets (see, for example, Nutrient Requirements for Dogs, National Academy of Sciences, Washington, D.C. 1974).

Also known in the prior art are the following United States patents: 1,071,218 Dyck - this relates to the preparation of a food for stock, cattle and the like by utilizing paunch contents of slaughtered cattle. It includes high heat and the addition of an acid, to the contents under pressure after which a neutralizing agent is added to neutralize the hydrochloric acid. The resultant material is then dried.

3,545,977 Stahler -this teaches the production of animal feed components through processing of the rumen content of slaughtered cattle. The solids and liquids are separate whereupon the solids are dried and sterilized after which they are pelletized.

The liquid content is flocculated and then sterilized and treated to provide a concentrated processed rumen liquor.

3,550,524 Brumagim - this deals with the treatment of paunch manure which is sterilized and the liquid removed. The liquid is then evaporated to concentrate the entrained solids.

4,011,345 Bartsch - this patent discloses an expanded semi-moist pet food which is sugarless and contains cereal grain to stabilize the expanded characteristics of the product.

4,037,002, Brumagim - this discusses the treatment of paunch manure by sterilizing and then mechanically separating the gross solids from the liquid and retaining the solids as animal feed. The residual solids in the neutralized liquids are concentrated by evaporation which are then re-cycled to remove further solids.

4,054,674 Barkert et al - this illustrates the preparation of a semi-moist animal food from condensed fish solubles and fish or meat autolysates.

4,211,797 Cante et awl this patent deals with a surface coating for a dog food from tallow and the like.

4,228,195 Priegnitz - this discloses a semi-moist pet food with the proteins being derived from oil seed and meat or meat by-product protein sources.

It is known that the provision of canned moist pet food is not the most economically effective way of supplying rations to domestic pets, since the process of production and the transportation of finished products are costly in relation to the nutritional value on a volumetric basis, due to the large proportion of water in the finished product. Again, the packaging is not readily recyclable with existing technology nor is the disposal thereof optimal.

It has, however, now been found that rumen contents, optionally with the wall of the rumen, or tripe, may be incorporated into a mixture including one or more of cereal products and by-products, legume products and by-products, meat and carcass products and by-products, vitamins, minerals and flavour additives, whereby the resultant mix may be processed by means of continuous cooking extrusion to give dry or semi-moist pet food in a variety of physical forms or shapes. The invention therefore permits the utilization of slaughterhouse wastes which could otherwise not be exploited effectively.

According to the invention, there is provided a pet food which includes between 0.5% and 50% by weight rumen contents from a ruminant animal with a moisture content of the pet food not exceeding 35% by weight.

Preferably, according to the present invention, there is provided a dry or semi-moist pet food containing rumen contents from a so-called ruminant animal and at least 5%, but not more than 45% protein, the said protein being derived in part from the rumen contents and the tripe which is optionally incorporated, but also from one or more of the other optionally present ingredients such as protein isolates or concentrates, cereal grains, processed cereals, cereal by-products, oilseeds, processed oilseeds, oilseed by-products, meat and fish materials such as meat meal, fish meal, meat and bone meal, bone meal and other materials which may be, but are not limited to, those materials broadly defined as agricultural raw materials and crops.The pet food optionally contains vitamins and minerals in amounts varying from zero to maximum amounts tolerated without symptoms of toxicity or overdosage, and flavour consituents such as garlic, indole, skatole, yeast, natural or synthetic meat or fish flavours and aniseed may also be added. Those preservatives which may be deemed appropriate, such as potassium sorbate or propylene glycol, may be added, and suitable preservatives will be readily apparent to those skilled in the art.

In one embodiment the dry or semi-moist pet food according to the present invention contains up to 50% of rumen contents from a ruminant animal, expressed on a dry weight basis, together with at least 5% but not more than 40% protein, the origin of the protein being as described above, as well as other consituents required to confer nutritional adequacy. Though it is possible, within the scope of the invention, to prepare a novel pet food, consisting for the major part, of rumen contents, this would of necessity involve a pre-process dyring or water-expulsion treatment for the rumen material, which, in its native state, contains about 80% by weight of water.Since fairly low proportions of rumen cmontents suffice for the purpose of obtaining a product with organoleptic appeal, pre-process drying or otherwise concentrating of rumen contents is not desirable and is only necessary when use of the said rumen contents as a source of protein, for example to replace soya bean meal, is envisaged. In this connection it should be noted that drying of rumen contents removes flavour constituents of appeal to dogs and it is therefore preferable that small amounts of fresh rumen contents are also incorporated into the product, such that organoleptic appeal is maintained.Other considerations, such as the crude fibre content of the finished product, will be apparent to those skilled in the art, though it must be noted that such factors depend to a considerable extent on the source of rumen contents, and in particular, on the recent diet of the ruminant animal from which the rumen contents are obtained.

In another embodiment, therefore, the novel pet food according to the present invention contains 0.1% to 22.0% of rumen contents from a ruminant animal, expressed on a dry matter basis, corresponding to incorporation of O.50,o to 60% rumen contents in their natural state into the mixture before processing together with at least 15%, but not more than 40% protein as well as vitamins, minerals, essential fatty acids and other dietary factors in amounts supplying recommended dietary allowances for carnivorous domestic pets, and in particular the dog. The pet food also contains appropriate flavouring agents, colourants and preservatives.

Yet another embodiment of the invention envisages the use of up to 60% rumen contents in their natural state, together with dried rumen contents, such that the finished product, after drying to 6% - 10% moisture content, contains 0.1% - 50% rumen contents on a dry matter basis together with appropriate amounts of other macro- and micro-nutrients. Such a pet food according to the invention still provides the advantage of organoleptic appeal, at the same time permitting substantial exploitation of a low-cost material, to wit rumen contents.For the purposes of this invention, it is understood that the definition of "rumen contents in their natural state" covers not only fresh rumen contents as obtained directly from the rumen of a ruminant animal, but also such rumen contents which have been subjected to a concentration procedure of a physical nature, such as water expulsion under pressure, filtration, centrifugation and the like.

Detailed description The novel pet food according to the invention enables provision of a ration to domestic pets, and in particular dogs and related domesticated species, which is nutritionally acceptable, supplies hitherto unidentified trace factors and is organoleptically attractive.

As used herein, the term dry or semi-moist pet food refers to a product in the form of granules, pellets or strands, obtained by extrusion under pressure through a die which imparts a shape to the product, the extruded materials passing the die being cut into lengths by a rotating knife or being further molded by sets of stamp dies. Generally, though not invariably, the mixture is heated during or before extrusion to temperatures of 50"C - 300"C by means of steam under pressure or by heat applied from another source such as electrical heaters. Moisture may be added during the process, by injection of water or steam, as may other substances. The product resulting from the extrusion may optionally be dried, and during the drying process other materials may be added, for example, heat labile vitamins may be added by spraying and/or the extruded forms may be sprayed with liquid tallow or another fat or other coating materials.

The preparation of the mixture of ingredients required for the described process will be obvious to those skilled in the art. For example, the rumen contents and tripe may be comminuted in an apparatus commonly designated a meat grinder or mincer, cereals may be milled to an appropriate consistency in a hammermill or other suitable milling apparatus, and the mixing can be achieved by means of a suitable mixer such as a ribbon blender. After mixing, the entire mix is optionally remilled in a hammermill or such like to give the optimal consistency for cooking extrusion.

When use is made only of rumen contents without the associated tripe, the initial comminution in a meat grinder is optional, since the material is frequently in such a form that it may immediately be blended with the other ingredients.

Ingredients may be dried when necessary. Generally, all ingredients other than rumen contents are obtainable with low moisture levels, and further drying before processing is not needed. Rumen contents may optionally be dried before incorporation into the mixture by means which are obvious to those skilled in the art, such as a tumble dryer, a drum dryer and such like, or the mixture itself may optionally be dried by the same means after incorporation of the rumen contents. Alternatively, rumen contents may be compressed to expel liquid, by which means the water content may be reduced to less than 50%.Usually, however, drying or water expulsion will not be needed unless a substantial use of rumen contents, for example, to supply protein, is envisaged, since the feed characteristics of the mixture containing the moist rumen contents will be appropriate for direct cooking extrusion and the higher moisture level thus imparted to the mixture reduces the requirements for addition of moisture during the extrusion process.

The kneading of the mixture of ingredients with liquid and the raising of the temperature and subsequent extrusion and shaping of the material may be carried out in an apparatus known as a continuous cooking extruder. A suitable apparatus is the X-200 extruder marketed by Wenger Manufacturing.

This apparatus includes the volumetric feeding of the final mixture of hot, wetted ingredients to a single worm screw made up of interchangeable modules running inside a barrel made up of interchangeable modules, such that the feed rate and degree of compression of the material, injections of liquid or steam, as well as heating or cooling of the material, can be adjusted to obtain the desired product.

The material is subsequently delivered by the worm screw to the final compression chamber at the end of the barrel from which it is released to the atmosphere through a shaped die which is so designed as to allow a proper expansion ofthe product, and to deliver the product in a pleasing shape. The product thus being extruded is then cut by a rotating knife into chunks of the desired size, and optionally transported to a drying ovenforfinal moisture reduction.

A further suitable apparatus is the cooker-extruder marketed by the Creusot-Loire Company of the BC 45 twin-screw or BC 72 twin-screw type. Such apparatus include the features of viol metric feeding of the mixture of ingredients as well as the water, a cooling system and interchangeable modulator elements together forming two screws and enabling successive transport, kneading and final compression of the ingredients.

The extrusion screws are enclosed in a sleeve. Thus, for example, the apparatus may include four interchangeable modular elements of variable length, each element itself having a variable pitch.

Final compression is carried out by means of the last modular element and in a compression chamber which may be conical or cylindrical in shape. Screw plates mounted at the outlet of the apparatus enable lumps of materials to be obtained directly in the desired physical shape. Alternatively, if desired, flat lumps of material may be obtained from a single slit situated in the terminal part of the apparatus.

It will be appreciated that any other apparatus equivalent to the above described apparatus may be used if desired, such as the expander-extruder-cookers manufactured by Anderson Ibec Division of the International Basic Economy Corporation.

The product obtained from a cooking extruder as described may sometimes require to be dried. In the case of a dry pet food, moisture levels of 6% - 10% are acceptable, and this moisture content can in some cases be achieved with product issuing directly from the extruder. If further drying is required, product may be passed immediately through an apparatus entitled a tunnel dryer, which may optionally also be fitted with facilities for spraying fat or other materials onto the product. Alternatively, product may be dried and optionally fat-coated in a tumble dryer, or if drying only is necessary, in any other suitable drying equipment.

In the case of semi-moist pet food, product issuing from the extruder generally does not require further drying.

The process of cooking-extrusion for the production of dry and semi-moist pet foods is of course known.

For example, U.S. patent 3,447,929 discloses a process for the manufacture of dry expanded pet foods from a mixture of proteinaceous materials and cereals while Canadian patent 978018 describes the use of glycerine or propylene glycol as a plasticizing agent to give a soft-textured dry product. A soft-textured product obtained by addition of lecithin is also disclosed in U.S. patent 3,908,025. The coating of dry pet foods with fat by spraying is revealed in U.S. patent 3,467,525, while a fibrous texture may be imparted to the product by extrusion through a die fitted with an air nozzle, as described in British patents 1,442,059; 1,454,429; and 1,464,409.The basic concept of a semi-moist pet food is described in U.S. patent 3,202,514 and the continuation-in-part 3,482,985, while other patents relate to use of starch hydrolysates (U.S. 3,489,574 and U.S. 3,516,838) soluble sugars (British patent 1,419,902) polyethylene glycol or corn syrup (U.S. 4,055,676) or low-molecular-weight polypeptides (France 2,226,935). There are also numerous patents relating to co-extruded products such as the product revealed in U.S. patent 3,916,029 consisting of semi-moist meat core surrounded by a dry expanded cereal shell.

Similarly, there are patents relating to the use of flavoring constituents, which may be applied in the form of a coating, such as hydrolyzed brewers yeast (U.S. 3,830,798) comminuted animal/fish viscera in fat (Canadian patent 962,517) material derived from proteinase treatment of animal viscera (Japanese patent 80 09709) or lactic acid fermentate (British patent 1,557,390).

According to one embodiment of the invention, the mixture containing the rumen contents is heated at a temperature exceeding 100"C before extrusion, in the presence of moisture (which may have been present in the original mixture or may be added during the heating process), such that on extrusion the product expands to a diameter greater than that of the die through which it is forced. In this way, a product is obtained which is essentially sterile and the density of the product may be varied by adjusting the moisture content of the mixture. The density may also be varied by changes in the composition of the mixture chosen for extrusion, as, for example, by changing the protein-carbohydrate ratio, or changing the type of carbohydrate present.

Particular pet foods according to the invention are those which have been essentially sterilized during the extrusion process and which contain 0.5% - 25% of rumen contents and 15% - 35% protein expressed on a dry matter basis, the rumen contents being of bovine or ovine origin.

The protein, carbohydrate, and fat or oil in the final product will be suppiied in part by the rumen contents, but are also derived from other ingredients chosen which in general are selected from ingredients or raw materials commonly available as commodities, processed commodities, or product or by-products of the food, agricultural or fisheries industries in the broadest sense of the word, thus including, for example, edible materials resulting from the degradation of cellulosic waste, the solid materials remaining after fermentation reactions, and the like.

The list below exemplifies typical constituents and ingredients which may be used in pet food formulations, either in the original form, milled to an appropriate consistency or processed into various fractions. Thus, for example, wheat is given in the list, and this is understood to cover, not only various strains of wheat, but also flour, flour by-products, middlings, grits and the like.The list is not to be interpreted as exhaustive or limiting, and further examples of such ingredients will be readily obvious to those skilled in the art: Alfalfa, residues of animal or poultry carcasses including blood and bone, barley, sugar beet, bread, brewers grains, distillers grains, calcium saits such as the phosphate or carbonate, milk and milk fractions, other dairy products and by-products, dried or otherwise, eggs, citrus residues, cocoanut residues, corn, cottonseed, crab, shrimp, animal fats, vegetable and fish oils, fish and fish residues, spent hops, linseed, flax, millet, molasses, oats, oyster shells, legumes such as peas and beans, groundnuts, potatoes, rye, sesame, rice, seaweeds, rapeseed, CANOLA (registered trademark), and other oilseeds, sorghum, soy beans, seed of evening primrose, sunflower seeds, sugar cane, tomatoes, wheat, triticale, yeast, residues from the fermentation of cellulosic biomass, protein derived from culture of bacteria, yeast, etc., and such other materials as may from time to time be shown to possess value as nutrients for mammals.

It is clear that the economics of the supply-and-demand situation will govern the choice of constituents and ingredients under practical conditions.

The following examples illustrate the invention: Example 1 An animal feed that is particularly attractive to dogs was prepared with the following composition: rumen (including tripe) (not dried) 35.0 kg corn 96.6 kg defatted soy 50.0 kg wheat middlings 22.2 kg meat and bone meal 37.5 kg preblend of: -dicalcium phosphate 2.5 kg -salt 2.5 kg - iron oxide 250.0 g -vitamin premix 375.0 g -trace mineral premix 25.0 g -zinc oxide 15.5 g -manganese oxide 1.9 g -copper sulphate 8.2 g - garlic powder 70.0 g 5.7 kg 247.0 kg The feed corn and the soy meal were hammermilled in a Prater Mill Model G5 HFS (5 HP drive motor) through a 4/64" half circle screen, then combined with wheat middlings, meat and bone meal, and the preblend.These ingredients were blended five minutes in a Torco Model R-1 2 (10 HP drive motor) ribbon blender. The rumen contents were added to the blender. The trip was ground into the blender, and all ingredients were blended for five minutes, then hammermilled through an 8/64" screen.

The material was extruded using a Wenger X-20 continuous cooking extruder. The moisture in the double conditioner was about 20%, the feeder was set 22 rpm, the double conditioner cylinder at 350 rpm and the main drive at 540 rpm. The material was passed through a 1" spacer and a sD round hole die to produce a continuous coherent stream which expanded after passage through the die to form a porous structure. This was cut into " lengths with a standard knife edge. A total of about 210 kg of material was recovered.

The product was dried to 8.7% moisture. The bulk density was 420 g/L. The protein (N x 6.25) was 28.6%, fat 4.0%, fibre 2.6%, and ash 10.9% on a dry matter basis. The amount of rumen contents (as dry material in the final product) was about 4%.

Example 2 A run parallel to Example 1 produced a dried product which was screened on a 1/11" screen. The fines were recycled. The product was placed in a Patterson Vacuum Tumble Dryer, size no. 196, which was preheated to 60"C. The animal feed was then sprayed with 3% by weight melted tallow and tumbled for 30 seconds. Example 3 A run similar to Example 1 was made, with the following formulation: rumen (including tripe) (not dried) 37.0 kg corn 97.3 kg defatted soy 51.0 kg second clears flour 24.0 kg meat and bone meal 37.5 kg preblend (as in Example 1) 5.7 kg 253.5 kg This product was dried to 8.4% moisture. The bulk density was 390 g/L. The protein (N x 6.25) was 25.3%, and the rumen material contributed 3.8% of the final product.

Example 4 A run similar to Example 1 was made with the following formulation: rumen (including tripe) (not dried) 75.0 kg corn 205.0 kg distillers dried grains (with solubles) 75.2 kg wheat middlings 53.1 kg meat and bone meal 100.3 kg preblend (as in Example 1) 11.4 kg 520.0 kg The product was dried to 9.2% moisture. The bulk density was 440 g/L. The protein (N x 6.25) was 24.4%, and the contribution of rumen material to the final product was 3.7%.

Example 5 A run similar to Example 1 was made with the following formulation: rumen (including tripe) (not dried) 73.5 kg corn 207.0 kg defatted soy 100.2 kg wheat millrun 52.6 kg meat and bone meal 75.3 kg preblend (as in Example 1) 11.5 kg 520.1 kg Artificial beef flavour was added to the double conditioner at 0.50%. The product was dried to 8.3% moisture.

The bulk density was 380 g/L. The protein (N x 6.25) was 27.3%, and the contribution of the rumen contents to the finished product was 3.7%.

Example 6 An animal feed that is particularly attractive to dogs was prepared with the following composition: rumen (contents only) (not dried) 90.5 kg corn 174.8 kg defatted soy 80.2 kg wheat millrun 40.2 kg meat and bone meal 59.7 kg preblend of: - decalcium phosphate 4.5 kg - salt 4.5 kg - iron oxide 450.0 g -vitamin premix 670.0 g -trace mineral premix 45.0 g -zinc oxide 27.7 g - manganese oxide 3.4 g -copper sulfate 14.7 g -garlic powder 125.0 g 10.3kg 455.7 kg The feed corn and the soy meal were hammermilled in a Prater Mill Model G5 HFS (5 HP drive motor) through a 4/64" half circle screen, then combined with wheat millrun, meat and bone meal, and the preblend.

These ingredients were blended five minutes in a Torco Model R-1 (10 HP drive motor) ribbon blender. The rumen contents were added to the blender, and all ingredients were blended for five minutes, then hammermilled through an 8/64" screen.

The material was extruded using a Wenger X-20 continuous cooking extruder. The moisture in the double conditioner was 27%, the feeder was set at 22 rpm, the double conditioner cylinder at 350 rpm and the main drive at 540 rpm. The material was passed through a 1" spacer and a 8" round hole die to produce a continuous coherent stream which expanded after passage through the die to form a porous structure. This was cut into 3" lengths with a standard knife edge. The product was dried to 8.8% moisture. The bulk density was 400 g/L. The protein (N x 6.25) was 26.9%, and the product contained 5.5% of rumen material.

Example 7 A run similar to Example 6 was made, with the following formulation: rumen (contents only) (not dried) 8.2 kg corn 151.4 kg defatted soy 39.7 kg wheat middlings 38.9 kg meat and bone meal 37.4 kg preblend (as in Example 6) 6.3 kg 281.9 kg The product was dried to 9.1% moisture. The bulk density was 360 g/L. The protein (N x 6.25) was 22.8%, and the product contained 0.8% rumen material.

Example 8 A run similar to Example 6 was made, with the following formulation: rumen (contents only) (not dried) 105.8 kg corn 277.6 kg defatted soy 10.0 kg wheat middlings 99.3 kg preblend (as in Example 6) 11.5 kg 504.2 kg The product was dried to 9.6% moisture. The bulk density was 360 g/L The protein (N x 6.25) was 14.2%, and the product contained 5.9% rumen material.

Example 9 A run similar to Example 6 was made, with the following formulation: rumen (contents only) (not dried) 48.6 kg corn 51.7 kg defatted soy 65.3 kg wheat middlings 9.7 kg meat and bone meal 66.1 kg preblend (as in Example 6) 5.8 kg 247.2 kg The product was dried to 8.5% moisture. The bulk density was 410 g/L. The protein (N x 6.25) was 36.7%, and the product contained 5.8% rumen material.

Example 10 An animal feed that is particularly attractive to dogs was prepared with the following composition: rumen (including tripe) (not dried) 34.0 kg corn 95.8 kg defatted soy 50.0 kg wheat middlings 22.5 kg meat and bone meal 37.5 kg preblend (as in Example 1) 5.7 kg 245.5 kg The material was prepared for extrusion as in Example 1. It was extruded using a Wenger X-20 continuous cooking extruder. Propylene glycol containing 0.025% potassium sorbate and 0.025% phosphoric acid was fed to the double conditioner such that the final product contained 2% of the propylene glycol by weight.

The moisture in the double conditioner was about 20%, the feeder was set at 34 rpm, the double conditioner cylinder at 350 rpm and the main drive at 540 rpm. The material was passed through a 1" die spacer and a 6 x 5/32" round hole die to produce a continuous coherent stream which expanded only slightly after passage through the die to form a dense structure. This was cut into 1" lengths with a standard knife edge. The product contained 13.9% moisture. The bulk density was 600 g/L. The protein (N x 6.25) was 28.3% and the product contained 3.5% rumen material.

Example 11 The contents of five fresh rumens were dried in a Patterson Vacuum Tumble Dryer at 60"C, giving 44.5 kg of rumen contents with a moisture content of 11% and a protein content (N x 6.25) of 31.2%. This material was used to prepare an animal feed of the following composition: rumen contents (not dried) 36.0 kg rumen contents (dried as above) 44.0 kg corn 90.0 kg wheat middlings 50.0 kg meat and bone meal 30.0 kg preblend (as in Example 1) 5.7 kg 255.7 kg The mixture was processed in a way similar to that described in Example 6, giving just over 200 kg of product with a bulk density of 460 g/L, protein content (N x 6.25) of 25.1% and containing about 23% rumen contents.

Example 12 The contents of six fresh rumens were dewaterized by passing through a helical screw expeller, giving 112 kg of material with a moisture content of 45%. This material was incorporated by the method of Example 1 into a mixture of the following composition: dewaterized rumen contents 110.0 kg corn 90.0 kg wheat middlings 30.0 kg meat and bone meal 30.0 kg preblend (as in Example 1) 5.7 kg 265.7 kg The material was extruded as described in Example 1, giving a pet food which was subsequently dried to 9.1% moisture, yield about 210 kg. The protein (N x 6.25) was 26.4% and the bulk density was 425 g/L. The material contained 28.5% rumen contents.

Example 13 A preference trial was performed using a Komondor dog, age 5 years, weight 60 kg. Quantities of each 400 grams of the product described in Example 1 (code B), a commercially-available high-protein dry dog food (26% protein, code A), and a commercially-available maintenance dry dog food (20% protein, code C) were weighed into coded plastic food dishes and placed in front of the dog under double-blind conditions (the investigator was unaware of the coding assigned) at his normal feeding time. The behaviour of the dog was observed. After olfactionof the three dishes, the dog commenced eating from the dish coded B which was revealed on breaking the code to be the novel dog food according to the invention.When the full 400 g from dish B had been consumed, the dog ate approximately 200 g from dish A (commercially-available high-protein dog food) before moving away from the food dishes. None of the maintenance type diet (code C) was consumed.

Example 14 Atrial similar to that of Example 13 was performed using a neutered King Charles Spaniel, age 6 years, weight 9.2 kg and coded food dishes containing 100 g samples of the three products tested in Example 11.

No olfaction was observed, and the dog was seen to eat for several seconds from each of the three dishes in turn. He then returned to the dish coded B containing the material from Example 1, and consumed the contents entirely before eating approximately 20 g from the dish coded C, containing the maintenance dry dog food.

Example 15 A preference trial was performed with the Komondor dog from Example 13 under double-blind conditions, using 400 g samples of the fat-coated product from Example 2 (fat content 7%), a commercially-available soft dry dog food (protein 18%, fat 7%), and a commercially-available fat-coated maintenance type dog food, beef-flavoured (protein 21%, fat 7%). Olfaction was observed after which the dog took small samples from each dish. He then returned to the dish containing the product from Example 2 and consumed this entirely, after which he ate small amounts from the other two dishes.

Example 16 A preference trial was performed with the King Charies Spaniel from Example 14 and 1009 samples of the products used in Example 13. There was no olfaction and the dog commenced eating indiscriminately from all three dishes, but with preference for the product from Example 2. When eating had ceased, amounts of food remaining were weighed and it was ascertained that 71 g of the novel product from Example 2 had been consumed against 13 g of the soft dry dog food and 159 of the fat-coated maintenance dog food.

Example 17 A preference trial was performed with the product from Example 12 and two commercially-available maintenance type dry dog foods, using the Komondor described in Example 13 and the King Charles Spaniel from Example 14. The trial was performed under double-blind conditions and resulted unequivocally in identification of the product from Example 12 as the most attractive for the two dogs tested.

Claims (1)

1. (1) A pet food which includes between 0.5% and 50% by weight rumen contents from a ruminant animal with a moisture content of the pet food not exceeding 35% by weight.

   (2) A pet food according to Claim 1 in which the moisture content of the pet food does not exceed 12% by weight.

   (3) A pet food according to Claims 1 or 2 which includes between 5% and 45% by weight of protein.

   (4) A pet food according to Claims 1 or 2 which includes between 15% and 30% by weight of protein (5) A pet food according to any of the preceding claims in which the rumen contents are between 5% and 35% by weight.

   (6) A pet food according to any of Claims 1 to 4 in which the ruman contents are between 15% and 25% by weight.

   (7) A pet food according to Claim 6 which includes between 18% and 30% by weight of protein.

   (8) A pet food according to any of the preceding claims which includes vitamins and minerals in amounts complying with recommended daily allowances for a dog.

   (9) A pet food according to Claim 1 which contains between 12% and 30% by weight of moisture.

   (10) A pet food according to Claim 9 containing between 5% and 45% by weight of protein.

   (11) A pet food according to Claim 9 which contains between 12% and 30% by weight of protein.

   (12) A pet food according to Claim 11 which contains between 5% and 30% by weight of rumen contents from a ruminant animal.

   (13) A pet food according to Claim 11 containing between 12% and 24% by weight of rumen contents from a ruminant animal.

   (14) A pet food according to any of Claims 9 to 13 which includes vitamins and minerals in amounts complying with recommended daily allowances for a dog.

   (15) A pet food according to any of Claims 1 to 7 and 9 to 13 which contains vitamins and minerals in amounts complying with recommended daily allowances for a cat.

   (16) A process for the manufacture of pet foods as claimed in any of the preceding claims, in which said process consists of the steps of first incorporating the rumen contents from a ruminant animal into a mix of edible materials commonly used for nutrition of domestic animals by conventional methods and then processing the mix by conventional methods to produce dyr or semi-moist pet food.

   (17) A pet food according to any of Claims 1 to 15 which contains appropriate preservatives, plasticizers, and fungistats.

   (18) A pet food according to any of Claims 1 to 15 and 17 in which the rumen contents are of bovine origin.

   (19) A pet food according to any of Claims 1 to 15 and 17 in which the rumen contents are of bovine origin.

   (20) A pet food as claimed in any of Claims 1 to 15 and 17 in which the rumen contents are from domesticated ruminant animals.

   (21) A process according to Claim 16 in which the rumen contents are of bovine origin.

   (22) A process according to Claim 16 in which the rumen contents are of bovine origin.

   (23) The process according to Claim 16 in which the rumen contents are from domesticated ruminant animals.

   (24) A pet food in the physical form of pellets, granules, chunks or strands, produced by the process according to Claims 16, 21,22 and 23.

   (25) A pet food which includes between 0.1% and 22% by weight of rumen contents from a ruminant animal expressed on a dry matter basis and corresponding to the incorporation of between 0.5% and 60% rumen contents in their natural state, and between 15% and 40% by weight of protein.

   (26) A pet food which includes up to 60% by weight of rumen contents in their natural state together with dried rumen contents whereby the finished product, after drying to approximately 6% to 10% moisture content, contains between 0.1% and 50% rumen contents on a dry matter basis.

   (27) A pet food substantially as described.

   (28) A pet food produced by the process substantially as described.

   (29) A pet food which includes between 0.5% and 50% by weight rumen contents and between 0.05% and 16% by weight tripe from a ruminant animal, with a moisture content of the pet food not exceeding 35% by weight.

   (30) A pet food which includes between 0.1% and 22% by weight of rumen contents and between 0.01% and 10% by weight of tripe from a ruminant animal expressed on a dry matter basis, corresponding to the incorporation of between 0.5% and 60% rumen contents and between 0.05% and 20% tripe in their natural states, and between 15% and 40% by weight of protein.

   (31) A pet food which includes up to 60% by weight of rumen contents and up to 20% tripe in their natural states, together with dried rumen contents and tripe, whereby the finished product, after drying to approximately 6% to 10% moisture content, contains between 0.1% and 50% rumen contents and up to 16% tripe on a dry matter basis.

   (32) A dry and semi-moist pet food formulation containing rumen contents from ruminant animals substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.