GB2257012A - Feedstuffs - Google Patents

Abstract

Use of crumbled pellets of compressed dry fibrous vegetable material, e.g. straw, as a carrier for liquid animal foodstuffs, e.g. molasses, oils or lipids.

Description

FEEDSTUFFS This invention relates to feedstuffs for animals.

In the specification of British patent application No.

9101830.9 filed on 29th January, 1991 we describe a novel material, granules of compressed dry fibrous vegetable material, especially crumbled pelleted alkali-treated straw, useful as animal bedding.

We have now found that this same material can be used very advantageously as an ingredient in the manufacture of animal feedstuffs, and especially as an aid in the addition of liquid components to compound feedstuffs.

For environment reasons, the burning of straw and stubble is being discouraged or banned. There is a need to find further uses for straw.

Chopped loose straw tends to be contaminated with weed seeds, mould spores, and plant disease organisms. Such contaminants can remain viable in the feed, and farmers are understandably reluctant to allow such contaminants to be excreted and returned to the land for fear that this may introduce or spread weeds and plant diseases. This could reduce the yield of subsequently planted crops, especially cereals.

However, finely ground straw is very dusty and presents health hazards in feed mills.

By the invention we provide an animal feedstuff ingredient, comprising granules of compressed dry fibrous vegetable material.

Preferably such granules have been blended with at least one liquid ingredient useful in animal feedstuffs. The quantity of such liquid ingredients carried by the granular material should not be so great that the moistened granular material cannot be handled by conventional animal feedstuff manufacturing equipment.

Moistening of the granular material can be conducted, for example, by spraying the liquid ingredient onto the granular material in an in-line mixer or in a batch process mixer such as a pan granulator.

The invention also encompasses the use of the granular material (with or without the prior addition of liquid feed ingredients) in the manufacture of compound animal feedstuffs, preferably by blending and extrusion with other solid feed components.

Preferably, prior to compression, the vegetable material has been ground, e.g. to pass a 7-10 mm screen. Grinding by means of a hammer mill destroys or reduces the viability of many of the weed seeds which may be present.

Preferably the compression of the vegetable material is achieved by pelleting, e.g. through the use of an animal-feeds ring-roll press, and the granules comprise the pelleted material that has subsequently been crumbled.

The moisture content of the granular material should not be greater than about 15% by weight, and generally will be in the range of about 10 to about 14% by weight.

Preferably the fibrous vegetable material comprises straw.

Wheat straw is preferred, but other types of straw can be used e.g. from barley, oats or rye. Fibrous vegetable material from a wide range of other cultivated plants can also be used. Generally, such material will comprise stalks, leaves and/or chaff. Such material is presently regarded as low value waste. Plants that are convenient sources of such waste are maize, sunflower, rape, and legumes such as peas and beans. The granular product of the invention can be derived from a mixture of such vegetable materials, if desired. A combination of straw and/or other vegetable fibres with sawdust or shavings is possible.

Preferably the granular material of the invention is of comparatively narrow particle size range (e.g. 1-10 mm), and preferably is essentially free from dust. A relatively uniform particle size, and comparatively high density, facilities the transport of the material, and the substantial absence of fines minimises potential health hazards caused by dust that may be experienced by persons handling the product.

A preferred process for the manufacture of granular material in accordance with the invention, involves chopping and grinding the fibrous vegetable material, compressing the material to form pellets, and crumbling these pellets to provide granules of appropriate size. Preferably the compression is achieved by extruding the vegetable material through a die of suitable diameter to form pellets (cylinders) of compacted material. The diameter and length of these cylinders is dictated by the size of the die holes and other parameters'that the skilled press operator can adjust as a matter of routine.

Crumbling of the resulting pellets can be achieved, for example, by passing them between closely-spaced rollers. The optimum gap between the rollers will depend on the size (diameter) of the pellets, but the gap will generally be at least about 1 mm, and generally not greater than about 10 mm. For typical cylindrical pellets of diameter about 8 mm, an optimum roller gap will usually be in the range of about 3 to about 8 mm. Preferably the rollers have a roughened rather than smooth surface, to promote passage of the pelleted material between the rollers.

Fluted rollers are ideal. By crumbling a pelleted material such as straw between rollers3 the cylindrical pellets tend to fracture into flakes or chips.

It may be necessary to dry the fibrous vegetable material, e.g. to a moisture content in the range 10-15% before it is chopped or ground. This can be achieved, for example, using forced current airflow.

The pellets emerging from a ring-roll press are hot (typical 0 temperature in the range 75-85 C) and comparatively soft. Moisture is lost as the pellets cool, and the 'cured' pellets are generally much firmer. Crumbling of the pellets can be performed before the pellets have cooled, which produces a small flake-like product, or after cooling which produces a higher proportion of larger fragments (chips).

During drying (if required in the process) the straw is usually subjected to air heated by a furnace, after chopping but before grinding. Extrusion subjects the vegetable material to elevated temperatures through friction. Mechanical working is applied to the material during these operations. The process of the invention therefore generates conditions under which undesirable contaminants in the vegetable material, such as weed seeds and mould spores, can be severely damaged. The processing of the material therefore significantly reduces the risk that feeds derived from the granulated product will contain viable contaminants which should not be returned to the land at a later stage.

In a preferred embodiment of the invention, a minor amount of alkali is added to the fibrous material before it is compressed or extruded. Caustic alkalis are preferred, and caustic soda (sodium hydroxide) is ideal.

The use of aqueous caustic alkali has the additional benefit of damaging bacteria and moulds which may be present.

The pelleting of caustic soda and straw to provide a straw-based material for use as an animal feedstuff ingredient is already well-known. Reference can be made to British Patent No.

1,366,138 (Unilever Limited). The co-extrusion of caustic soda and straw results in chemical breakdown of the straw and provides a product which is much more easily digested by ruminant animals. In addition to enhancing the feed value of the product, the present of the alkali during the extrusion step facilities the processing because the alkali acts as a lubricant. However, it has not previously been suggested that pelleted alkali-treated straw could be used in crumbled form as a carrier for liquid components in the manufacture of animal feeds.

The addition of alkali to straw or other fibrous vegetable material in the manufacture of a product according to the present invention is especially beneficial. Not merely does the alkali act as a lubricant (pelleting aid), but the exothermic chemical reaction caused by the alkali helps to inactivate any contaminating weed seeds, spores or other micro-organisms present in the vegetable material. Although quite high levels of alkali can be included (to make a nutritionally improved straw feedstuff ingredient the optimum level of sodium hydroxide is typically about 4 to about 5% on a dry weight basis), the advantages in the present invention can be achieved with much lower alkali inclusion levels. Preferably, the alkali level is at least about 0.1% by weight. Alkali levels in the range of about 0.25% up to about 1.5% are ideal.

A further benefit associated with the incorporation of sodium hydroxide in the material is that the salt (sodium chloride) level in the diet administered to the animals may be reduced. Lower salt feed intake levels result in less demand for drinking water.

Other pelleting aids, such as mineral silicates e.g. talcum, to complement or replace the alkali, can be added if desired.

Removal of fines from the product can be achieved by sieving.

However, in a preferred process the fines are removed by aspirating the crumbled material, preferably while it is being cooled, e.g. progressing through a fluid bed cooler or other aspiration apparatus. Air is passed through the flowing crumbled material at a velocity sufficient to lift the material and draw off the fines.

The drying, grinding and pelleting operations associated with the manufacture of a product of the invention will generally need to be conducted in a factory or similar well-equipped facility.

The final crumbled product can also be manufactured in such a facility, and distributed therefrom to the customer in ready-to-use form. However, an alternative embodiment of the invention involves central manufacture of the pelleted product, followed by transport of the intact pellets to the customer and crumbling of the pellets to provide the granular material for use in feed manufacture on-site. Bulk transport of the material in the form of intact pellets will be more economic.

Production of the pelleted material in dedicated centralised facilities which are not directly involved in the handling of feed materials or livestock can minimise the risk of accidental contamination of the material with livestock disease organisms such as salmonella.

The granular material of the invention can be used as a carrier for liquid ingredients in animal feedstuffs such as molasses and lipids (fats or oils, such as tallow, palm oil, soya oil, fatty acid distillates and fish oil). Mixtures of molasses and one or more lipids can be used. Generally the total amount of liquid materials added to the granular material will be at least about 5% by weight and more usually at least about 10% by weight.

In general not more than about 40% by weight in total of such liquids will be blended with the granular material.

The granular material that has been moistened with the molasses and/or lipids can be mixed with normal dry feed ingredients, such as cereals, oil-seed meal and proteins, to provide a compound feedstuff. Any of the additives, such as vitamins and mineral supplements, that are normally included in compound feedstuffs can also be added. Generally, the amount of moistened granular material in the compound feed will be at least about 5% by weight, preferably at least 10%. Usually the amount is not greater than about 25% by weight, more usually not greater than than 20%. Normally such compounds are prepared by extrusion (e.g. through a ring-roll press to provide animal feedstuff pellets). The granular material of the invention can therefore be used advantageously in the manufacture of feedstuffs for a wide range of domesticated animals such as cattle, sheep, pigs, horses and poultry.

Primary advantages of the granular material of the invention are: 1. Absorbent carrier for molasses, oils and fats, and fermentation solubles.

2. Reduces difficulties in handling such liquids in feed mills and on-farm, and obviates the high cost of drying.

3. The granular material is friable, and can be mixed easily with cereals, proteins and other dietary components.

4. Enhanced addition levels of sweetener (molasses) and fats/oils makes a compound feed more palatable.

5. Reduces dustiness of the compound mixture to which the molasses or fat is added.

6. Conventional carriers rely on absorbency (soaking into) or adsorbency (surface film). The material of the invention utilises both phenomena.

7. Inert carriers conventionally used, e.g. Vermiculite or Perlite, have no nutritional value and dilute the total energy contribution.

8. Conventional wood products e.g. sawdust and woodflour, have no nutritional value, and may soon be banned.

9. Conventional ground straw is light and dusty.

The granular material of the invention has: a) Better texture - more friable and open than many conventional carriers.

b) Nutritionally upgraded - higher nutritional worth.

c) Mould free, because the alkali tends to sterilise.

d) Less dusty - lower irritant, allergy less likely.

e) Greater density - lower transport costs.

f) Fewer weed seeds - grinding, alkali treatment and heat treatment dramatically reduce weed seed viability (seeds may be passed out on to pasture).

Claims (40)

1. An animal feedstuff ingredient comprising granules of compressed dry fibrous vegetable material.

2. An ingredient as claimed in claim 1, wherein the granules are pellets or pellets that have been crumbled e.g. to form flakes or chips.

3. An ingredient as claimed in claim 1 or claim 2, having a moisture content of not more than 15% by weight.

4. An ingredient as claimed in claim 3, having a moisture content of 10 to 14% by weight.

5. An ingredient as claimed in any one of claims 1 to 4, including a liquid animal feedstuff.

6. An ingredient as claimed in claim 5, wherein the liquid animal feedstuff comprises molasses and/or lipids and/or fermentation solubles.

7. An ingredient as claimed in claim 6, wherein the lipid is a fat and/or an oil.

8. An ingredient as claimed in claim 6, wherein the lipid comprises one or more of tallow, palm oil, soya oil, fatty acid distillates and fish oil.

9. An ingredient as claimed in any one of claims 5 to 8, which includes at least 5% by weight of such liquid feedstuff.

10. An ingredient as claimed in claim 9, wherein the amount of the liquid feedstuff is at least 10% by weight.

11. An ingredient as claimed in claim 9 or claim 10, wherein the amount of the liquid feedstuff is not greater than 40% by weight.

12. An ingredient as claimed in any one of claims 1 to 11, wherein the vegetable material comprises straw from wheat, barley, oats or rye and/or stalks, leaves and/or chaff of other cultivated plants.

13. An ingredient as claimed in claim 12, wherein the said other cultivated plants comprise maize, sunflower, rape and/or legumes.

14. An ingredient as claimed in any one of claims 1 to 13, wherein the granules have a particle size of 1 to 10 mm.

15. An ingredient as claimed in any one of claims 1 to 14, which includes an alkali.

16. An ingredient as claimed in claim 15, wherein the amount of alkali is from 0.1 to 5% by weight based on the dry matter weight of the granules.

17. An ingredient as claimed in claim 16, wherein the amount of alkali is from 0.25 to 1.5% based on the dry weight of the granules.

18. An ingredient as claimed in any one of claims 15 to 17, wherein the alkali is sodium hydroxide.

19. An animal fodder composition comprising an ingredient as claimed in any one of claims 1 to 18 in admixture with other fodder materials and/or fodder additives.

20. A composition as claimed in claim 19, wherein the amount of the said ingredient is at least 5% by weight.

21. A composition as claimed in claim 20, wherein the amount of the said ingredient is at least 10% weight.

22. A composition as claimed in any one of claims 19 to 21, wherein the amount of the said ingredient is not greater than 25% by weight.

23. A composition as claimed in claim 22, wherein the amount of the said ingredient is not greater than 20% by weight.

24. A method of feeding animals comprising feeding them an ingredient as claimed in any one of claims 1 to 18 and/or a fodder composition as claimed in any one of claims 19 to 23.

24. A process of making an animal feedstuff ingredient which comprises compressing dry fibrous vegetable material to form granules.

25. A process as claimed in claim 24, wherein the vegetable material is compressed into pellets, which are subsequently crumbled to form the said granules.

26. A process as claimed in claim 25, wherein the pellets are crumbled in situ on the farm.

27. A process as claimed in any one of claims 24 to 26, wherein prior to compression the vegetable material is chopped and/or ground.

28. A process as claimed in claim 27, wherein the vegetable material is ground to a particle size that will pass through a 7 to 10 mm screen.

29. A process as claimed in claim 27 or 28, wherein the vegetable material is ground in a hammer mill.

30. A process as claimed in any one of claims 27 to 29, wherein the vegetable material is dried before it is chopped or ground.

31. A process as claimed in claim 30, wherein the fibrous material is dried to a moisture content of 10 to 15% by weight.

32. A process as claimed in any one of claims 24 to 31, which includes mixing an alkali.

33. A process as claimed in claim 32, wherein the alkali is sodium hydroxide.

34. A process as claimed in claim 32 or claim 33, wherein the alkali is present in an amount of 0.1 to 5% by weight based on the dry matter weight of the granules.

35. A process as claimed in claim 34, wherein the said amount of alkali is from 0.25 to 1.5% by weight.

36. A process as claimed in any one of claims 24 to 31, which includes adsorbing and/or absorbing liquid animal feed on the said granules.

37. A process as claimed in claim 32, wherein the liquid animal feedstuff is as claimed in any one of claims 6 to 8.

38. A feedstuff ingredient as claimed in claim 1 substantially as hereinbefore described.

39. A process as claimed in claim 24, substantially as hereinbefore described.

40. A fodder composition as claimed in claim 19, substantially as hereinbefore described.