GB2141316A - Animal feedstuff - Google Patents

Abstract

In a process for preparing a feedstuff for ruminants, a cellulosic material, e.g. straw, is ammoniated by treatment with gaseous ammonia or by admixing with an NH4 cation generating agent. The cellulosic material is coated with a liquid proteinaceous material, e.g. liquid yeast, and the coated material is dried at an elevated temperature to volatilize the ammonia. The resultant feedstuff has an enhanced nutritional value, the digestibility of the cellulosic material is improved, and the proteinaceous material protected against digestion in the rumen.

Description

SPECIFIg:ATION Animal feedstuff The invention relates to a process for preparing animal feedstuffs, and to an animal feedstuff prepared by the process. The invention is particularly concerned with a process for treating cellulosic materials to provide a high quality feedstuff for ruminants.

It is known, from Example from U.S. Patent Specification No. 4,064,276 and U.K. Patent Specifications Nos.

2,103,91 6A and 2,082,039B to improve the feed value of straw, and other plant materials containing lignocellulose, by treating the straw or other materials with ammonia. Usually the straw is treated with gaseous ammonia or is mixed with urea, and is left to stand for periods of from 10 days up to 3 months to permit decomposition of the lignocellulose to take place.

It is an object of the invention to provide an improved process for treating cellulosic materials to prepare an animal feedstuff suitable for ruminants which is highly palatable and has increased digestibility and metabolizable energy values. It is a further object of the invention to provide a process in which the ammoniation of the cellulosic material may take place in a short period of time.

According to the present invention there is provided a process for preparing an animal feedstuff which comprises the comminution and ammoniation of a cellulose-containing material, wherein the cellulosecontaining material is pre-ammoniated and/or is mixed with an NH4 cation generating agent and is coated with a proteinaceous substance and wherein the coated material is subjected to drying at an elevated temperature sufficient to volatilize ammonia generating compounds or complexes present in the material.

Preferably, the cellulose containing material may comprise one or more of the following : Cereal straws, such as oats, wheat, barley, rice, rye, corn stover; Milo and sorghum straws; Bagasse; Wood by-products; Grain screenings, chaffs, or grain dusts; Ru men paunch contents, preferably in dried or dewatered form; Malt combings, or other non-toxic cellulosic biomass material.

The cellulose containing carrier material is shredded into lengths of from about 5 cm to about 10 cm, suitably after the ammoniation step but before the coating step.

The proteinaceous material used in coating the comminuted cellulose-containing material suitably is in liquid form and may comprise one or more of the following: Brewers' waste yeast; Yeast waste from alcohol fermentation industry; Concentrated vinasses; Proteinaceous sludges; Skim milk, wheys or other dairy by-products; Microbial proteins separated from substrate; Microbial proteins with edible substrate; Microbial proteins grown on cellulose materials.

In a further embodiment the comminuted cellulose-containing material is used as a substrate for the growth of yeasts or other microrganisms having a good value for ruminants. In this embodiment the NH4 cation generating agent is mixed with the cellulosic material and the mixture is inoculated with a suitable microorganism, e.g. Trichoderma viride. The cellulose and nitrogen from the NH4 cation generating agent act as nutrients for the growth of the microorganism to enhance the feed value of the cellulosic material and to form the proteinaceous coating on the cellulose. Additional cellulose-containing material, proteinaceous material, and/or additional NH4 cation generating agent, may be added as desired, and the mixture is fed to the drierwhere volatilization of ammonia occurs.

Suitably, the coated material may be further enhanced before drying by the addition of any of the following:- molasses, brewers' or distillers' by-products (usually wet), wet beet pulp, animal and vegetable fats and oils, timber and paper industry liquid wastes, potato and potato industry wastes, other vegetable wastes, root crops, wet rumen paunch contents, fats from food industry wash water e.g. butter making, other food industry wastes and by-products, mineral mixes balanced for microbial growth, mineral mixes balanced for ruminants, salt, formaldehyde, and chelated minerals.

The dried feedstuff material of the invention may be ground, further processed and/or blended with other feed ingredients before being fed to ruminants. Preferably the material is formed into pellets using a conventional pelleting press. Grinding of the material is not necessary before feeding, but if carried out would be to a fineness dictated by market and further processing requirements.

The proportions of the various ingredients us.ed in the process of the invention may vary depending on specific ingredients used, the following approximate ranges have been found suitable: Range (% of dry matter) Straw or other cellulose material: 20%-S0% Liquid yeast 5%35% Molasses -10%-35% Urea (or equivalent) 2%-- 5% Other materials 0%25% Tests have indicated that where the higher-levels of liquid yeast are used control of the molasses level will help reduce the extent of malliard type reations between sugarand nitrogenous components.

In carrying out the process the cellulosic material is either pre-treated with gaseous ammonia or is intimately mixed with the NH4 cation generating agent. The mixing may be carried out batch-wise or as part of a continuous process before the material is coated with the proteinaceous material. Shredding of the cellulosic material may take place before or after ammoniation but preferably before coating with the proteinaceous material. The coated material is then passed to a drier.For reasons of efficiency direct fired drying is preferable and a drum drier has been found to be suitable. It is important that the temperature of the drier is sufficiently high to volatilize the ammonia present in the materials mixture. Apartfrom this requirement, the drier conditions may be adjusted to optimize drying efficiency while minimizing overheating losses. Using a direct fired drum drier it has been found that suitably the inlet temperature of the drier is in the range 400"C to 8000C, preferably between 600"C and 650"C, while the exhaust temperature of the drier is in the range 80"C to 1 350C, preferably between 1 00 C and 1 20 C.

The process may be a continuous process and where the cellulosic material is not pre-treated with ammonia, ammoniation of the cellulose, or additional ammoniation in the case of pretreated material, takes place in a matter of minutes in the drier. A suitable dwell time in the drier is between 0.5 and 5 minutes.

It has been found that the process of the invention produces animal feedstuffs which: 1. are very palatable and can form the major part of a ruminant's dietary regimen.

2. have increased digestibility and metabolizable energy values for ruminants over and above those expected (calculated) from the sum of values for the individual ingredients in the product.

3. have nitrogen levels which show no significant losses throughout the process.

4. show significant reductions in the expected rate of nitrogen disappearance in the rumen. The amounts of crude protein which are subsequently digested in the lower gut are significantly increased. This "protected" protein represents an enhancement of the crude protein quality for ruminant feeding.

5. represent the conversion of wasted or poorly used by-products of agriculture or industry into high quality animal feeds.

It-is believed that the increase in digestibility of the straw and other fibres is probably caused by the NH4 cations accessing and reacting with the micro-structural components of the lignocellulose complex (c.f.

Bergner, H. (1980). ARCH. TIERBRNAN RUNG, 30, 239-256, CHEMISCHE GRUNDLA GEN DES STROHA UFS CHLUSSES IN DER PELLETIERPRRESSE.(Ammonia treatment can be carried out in part as a pretreatment, using ammonia gas and water, or other NH4 generating agents, under known conditions of time, temperature and pressure (e.g. Lawlor, M.J. and O'Shea J., (1979). THEEFFECTOFAMMONIATION ON THE INTAKEAND NUTRITIVE VALUE OFSTRAW. Anim. Feed Science Tech. 4, 169-175). However, the subsequent high temperature drying, of the process of the present invention appears to augment the dry matter digestibility and MEr values.Certainly, the high temperature drying of a mixture containing urea (or other NH4 cation generating agents) mixed intimately with the fibres appears to release NH4 cations to react with the fibre and leave the cellulose crystals more available to subsequent digestion.

Coincident with and in synergism with this effect on cellulose digestibility the high temperature drying has other desirable effects, when either the ammonia pretreated fibres, or the mix of fibre and NH4 cation particles are coated with a liquid proteinaceous material (e.g. brewer's liquid yeast) before drying. Firstly, the proteinaceous components are rendered more resistant to subsequent digestion in the rumen i.e. the protein is "protected". Also the freed NH4 cations and other non-protein-nitrogen (NPN) materials are apparently absorbed or adsorbed on the fine structure of the feed particles and not lost to the atmosphere throughout the process.

The combination of these reactions can, on the one hand, give fibre digestibility advantages similar to those observed after oxidation and ammonification (Terashima, Y, Torisu, I. and Itoh H. (1980), EFFECTS OF SODIUM CHLORITEANDAMMONIA TREATMENT ON THE 'IN VITRO'DIGESTIBILITYOFLOW QUALITY ROUGHAGES, Jap. J. Zootech, Sci. 51(1), 40-47), as well as on the other hand, allow little or no nitrogen - losses while affording "protection" to the protein typical of judicious heat treatment.

Pretreatment of the proteinaceous materials with formaldehyde may help to augment the protein "protection" effect of the heating in some cases, and in such situations can usefully be incorporated into the process.

In other cases over "protection" of protein can occur and formaldehyde treatment is not desirable. Both formaldehyde-and/or salt can be used to inactivate live waste yeasts.

The invention is further illustrated by means of the following Examples.

Example 1 Barley straw was treated with 4% w/w ammonia gas in a commercially available "oven" for 23 hours under suitable conditions of pressure and temperature. The straw was then shredded, to 5cm lengths, in a tub grinder and pneumatically conveyed to a mixer where it was mixed with brewery yeast waste and molasses in a ratio of their dry weight of 77.5%: 4.5%: 18.0% for straw, yeast and molasses respectively. The resultant mixture (which had a moisture content of 50% approximately) was passed through a rotary drum drier of the direct drying, oil fired furnace type) with the exhaust temperature set at 121"C, pneumaticaly conveyed to a hammer mill and ground through 3mm screens.

The product was further mixed with molasses (10%) and soyabean meal (10%) and pelleted (8 mm die) to give a final product which approximated to the analyses of cereal replacer pellets.

The pelleted product was tested in a commercial feed mill, where it was used as a direct substitute for a cereal replacer pellets (C.R.P.) at 25% inclusion in a commercial dairy feed compound. Samples both of the commercial dairy feed (control), the dairy feed compound containing pellets of the invention (experimental), the commercial C.R.P., and the pellets of the invention were taken.

Both control and experimental dairy feeds were fed under normal conditions on a number of dairy farms with satisfactory results.

Samples of the ingredients used in the process of the invention, samples of the C.R.P, samples taken at intermediate stages of the process, and final products were analysed both chemically and in vitro (by the Tilly & Terry in vitro dry matter digestibility method). Analyses were aimed at monitoring changes in metabolizable energy (MEr) and crude protein (C.P.) contents. MEr values for ammoniated straw and yeast were calculated from proximate (Weende) analyses using equations contained in Bulletin 33, Energy allowances and feeding systems for Ruminants, H.M.S. O. These calculated values approximated the table values (Bull. 33). All other MEr determinations were based on direct in vitro digestibility of dry matter (D.M.D.) tests carried out by the Irish Agricultural Institute, Dunsinea, Castleknock, Co. Dublin.Crude potein (C.P.) was determined by the Kjeldahl method both for direct C.P. measurements and for rate of protein digestion studies (see below).

Operations outline and sampling points

SAMPLE I Wet mixing SAMPLE II Blending & BR< trying & Grinding > Pelleting (Ingredients) (Post drying) SAMPLE On-Farm | SAMPLE IV | Dairy Feed | - SAMPLE Ill Feeding Feeding | < | Manufacture | (Dairy Feeds) (Blended product) Metabolizable energy changes ME (MJ/Kg) Determined Expected (From in vitro DMD) (Calculated from Ingredients) Sampled a) POST DRYING (Sample II) 9.16 8.22 b) BLENDED PRODUCT: (Sample III) Experimental 10.40 9.74 Commercial C.R.P. 8.39 c) DAIRY FEED: (Sample IV) Experimental 11.71 Control 11.21 Contribution of experiments blended Productto MErof Dairy feed 10.40 10.40 Rate of protein digestion-postdrying sample (sample 11) Crude Protein (% in Dry Mutter) 10.33 Crude Protein Digested after 48 hours in vitro digestion (at rumen pH 43.7% Crude Protein digested after a further 48 hours in vitro digestion (with acidification and addition of pepsin) 30.4% Observations 1. After allowing for the improved MEr inthe ammonia treated straw, the determined MEr was 11.4% greater in the post drying-sample than expected (9.16 v's 8.22).

2. The blended product (with 10% molasses and 10% soyabean meal added) had a greater MEr (10.40 v's 9.74) than expected, so there appears to be further enhancement of the product due to blending and pelleting.

3. This enhanced MEr value was carried through to-the experimental dairy feed.

4. The rate of protein digestion studies indicate that a substantial amount of crude protein is "protected" and is not digested in the rumen enviroment but is digested in the lower gut enviroment.

Example Il Ammoniated barley straw, brewers' liquid yeast and molasses were mixed and processed as for Example I with the following changes: i) The ingredients were mixed in a ratio of their dry weights of 64.0:13.1:22.9 for straw, yeast and molasses respectively.

ii) The moisture content of the net mixture was adjusted to 65% by the addition of water.

iii) The drier exhaust temperature was 80C.

iv) The product was not further treated after drying and grinding.

v) Sampling and analyses were aimed principally at constrasting changes in metabolisable energy (MEr) and crude protein (C.P) before and after drying.

Operations outline and sampling points

Sample I T WET | Sample II IDRYING & Sample III MIXING . MIXING | ) GRINDING (Ingredients) (Pre drying) GRINING (Post drying) Chances in metabolizable energy IMErJ and crude protein (C. P.) MET (MJ/Kg) C.P. (%) Determined Expected Determined PREDRYING 8.55 8.40 10.4 POST DRYING 8.98 8.55 10.3 Rate ofprotein digestion (Sample) Predrying Post drying (Sample II) (Sample Ill) C.P. digested after 48 hours in vitro(at rumen pH). 57.7% 34.0% C.P. digested after a further 48 hours in vitro (with acidification and addition of pepsin) 15.4% 35.2% Observations 1.After allowing for the improved MEr in the ammonia treated straw the determined MEr (postdrying) was greaterthan expected (predrying), (8.98 V's 8.40). This improvement was mainly due to changes during the drying process (8.98 V's 8.55).

2.There was no observed crude protein loss due to drying.

3. The rate of protein digestion studies indicate a highly significant improvement in protein protection between pre and post drying samples. This redistribution of protein digestion from the rumen environment to the lower gut environment has very important advantages for ruminant feeding.

Example IIl Conditions and procedures were similarto Example II except that: i) the straw was not ammoniated or pretreated but urea was included in the wet mix.

ii) The wet mix was adjusted to 57% moisture by the addition of water.

iii) The ingredients were mixed in a ratio of their dry weights of 70.6:9.5:16.7:3.2 for straw, yeast, molasses and urea respectively.

iv) Sampling and analyses were aimed principally at contrasting determined and expected values for both metabolizable energy (MEr) and crude protein (C.P.) before and after drying.

Operations outline and sampling points

Sample I | WET | Sample II | DRYING & | Sample lil > | MIXING | ) GRINDING (Ingredients) (Predrying) (Postdrying) Changes in metabolizable energy (MErJ and crude protein (C. P.) MEr (MJ/KG) %C.P.

Determined Expected Determined Expected Predrying 6.87 6.70 13.5 15.5 Postdrying 8.06 6.87 14.5 13.5 Observations 1. The MEr increased by 17.3% (8.06 v's 6.87) as a result of reactions in the dryer.

2. There was no crude protein loss during drying.

Example IV A 500 kg. dry matter batch of feedstuff was prepared containing the followingingredients: Straw 330 kg Liquid yeast 375 kg Molasses 128 kg Molasses (added at pelleting stage) 52kg Urea 20kg A portion of the liquid yeast was first put in a mixer, followed by the urea, with continuous agitation of the mixer to ensure dispersion of the urea in the yeast. The straw is shredded into the mixer during agitation, after which the remainder of the yeast was added. Finally, the molasses was added. Agitation continued until the ingredients were intimately mixed. The mixture was conveyed to an oil-fired rotary drier, where it was dried at an exhaust temperature of 100"C. The dried material was pneumatically conveyed from the drier to a grinder where it was ground through a 3mm screen. The ground material was fed directly to a pelleting press where the additional molasses was added before pelleting through a 20 mm die.

Example V Semi - solid Fermentation Process Rye-grass Lolium multiflorum is sun-dried and-grund through a 20 mesh screen. The grass is mixed with 0.5 N sulphuric acid in the ratio 1 part ground grass to 3 parts acid. The mix is heated in a pressure cooker at 120"C for 30 minutes. The resultant product is cooled to room temperature and ammonium hydroxide is added to adjust the pH to 4.2. The product is then inoculated with 5%, by weight, of Trichoderma viride culture. The inocultated substance is placed in losely capped bottles, which are attached to a tumbling device, and are tumbled for3 days at room temperature. In this examplethe protein content was increased from 3.1% in control ground grass to 10.9% in the treated grass. The substance so produced is then dried in a drier, as described previously, to cause volatilization of the ammonia. The inoculated rye-g rass may form the sole source of cellulosic material in the process of the invention, or additional cellulosic material may be added.

Example Vl The process of Example V was repeated using, instead of Trichoderma viride, the yeast Candida utilis. The fermented ground rye-grass was found to have a protein content of 12.4%, compared to 3.1% in the control ground grass.

Claims (16)

1. A process for preparing an animal feedstuff which comprises the comminution and amrnoniation of a cellulose-containing material, wherein the cellulose-containing material is pre-ammoniated and/or is mixed with an NH4 cation generating agent and is coated with a proteinaceous substance and wherein the coated material is subjected to drying at an elevated temperature sufficient to volatilize ammonia generating compounds or complexes present in the material.

2. A process as claimed in claim 1, wherein the ammoniation of the cellulose-containing material is effected by treating the material with gaseous ammonia, and/or mixing the material with an NH4 cation generating agent.

3. A process as claimed in claim 2, wherein the NH4 cation generating agent comprises ammonia gas and water, urea, ammonium bicarbonate, ammonium hydroxide, an ammonium salt, or ureaformaldehyde.

4. A process as claimed in any of the preceding claims wherein the cellulose-containing material comprises one or more of the following :- Cereal straws, such as oats, wheat, barley, rice, rye, corn stover; Milo and sorghum straws; Bagasse; Wood by-products; Grain screenings, chaffs, or grain dusts; Rumer paunch contents, preferably in dried or dewatered form; Malt combings, or other non-toxic cellulosic biomass material.

5. A process as claimed in any of the preceding claims wherein the proteinaceous material is in liquid form and comprises one or more of the following: Brewers' waste yeast; Yeast waste from alcohol fermentation industry; Concentrated vinasses; Proteinaceous sludges; Skim milk, wheys or other dairy by-products; Microbial proteins separated from substrate; Microbial proteins with edible substrate; Microbial proteins grown on cellulose materials.

6. A process as claimed in any of the preceding claims wherein one or more of the following substances is added to the feedstuff material:- molasses, brewers' or distillers' by-products, wet beet pulp, animal and vegetable fats and oils, timber and paper industry liquid wastes, potato and potato industry wastes, other vegetable wastes, root crops, wet rumen paunch contents, fats from dairy industry wash water, other food industry wastes and by-products, mineral mixes balanced for microbial growth,-mineral mixes balanced for ruminants, salt, formaldehyde, and chelated minerals.

7. A process as claimed in any of the preceding claims wherein.drying-is carried out in a drier which has an inlet temperature in the range-400'C to 800"C and an outlet temperature in the range 80"C to-1350C.

8. process as claimed in claim 7 wherein the inlet temperature is in the range 600"C to 650 C and the outlet temperature is in the range 100"C and 1200C.

9. A process as claimed in claim 1, wherein all or part of the cellulose-containing material is in the form of a substrate on which is grown a yeast or other microorganism in the presence of an NH4 cation generating agent, the yeast or other microorganism forming all or part of the proteinaceous substance, and wherein additional NH4 cation generating agent is added to the cellulose-containing material if required, end the material is fed to the drier where volatilization of the NH4 cation generating agent occurs.

10. An animal feedstuff for ruminants comprising an ammoniated, comminuted, cellulose-containing material coated with a proteinaceous material, which has been subjected to elevated temperature in a drier to increase the digestibility of the cellulose-containing material and to render the proteinaceous material resistant to digestion in the rumen.

11. An animal feedstuff as claimed in claim 10, wherein the cellulose-containing material is comprised of one or more of the following: Cereal straws, such as oats, wheat, barley, rice, rye, corn stover; Milo and sorghum straws; Bagasse; Wood by-products; Grain screenings, chaffs, or grain dusts; Rumer paunch contents, preferably in dried or dewatered form; Malt combings, or other non-toxic cellulosic biomass material.

and the proteinaceous materialis comprised of one or more of the following: Brewers' waste yeast; Yeast waste from alcohol fermentation industry; Concentrated vinasses; Proteinaceous sludges; Skim milk, wheys or other dairy by-products; Microbial proteins separated from substrate; Microbial proteins with edible substrate; Microbial proteins grown on cellulose materials.

12. An animal feedstuff as claimed in either of claims 10 or 11, in which the ingredients are present in the following proportions: Range (% of dry matter) Straw or other cellulose material: 20% - 80% Liquid yeast 5% - 35% Molasses 10% - 35% Urea (or equivalent) 2% - 5% Other materials 0% -25%

13. An animal feedstuff as claimed in any of claims 10 to 12 wherein the cellulose-containing material is in the form of a substrate on which is grown a yeast or other microorganism having a food value for ruminants.

14. A process for preparing an animal teedstuff substantially as herein described with reference to any one of the Examples.

15. An animal feedstuff substantially as herein described with reference to any one of the Examples.

16. An animal feedstuff whenever prepared or incorporating material prepared by a process as claimed in any one of Claims 1 to 9 or 14.