CA1208063A - Feed supplement for ruminant animals - Google Patents

Abstract

Abstract Disclosed is a feed for ruminant animals compris-ing homogeneous particles of material characterized by being solid, flowable, and hydrolytically stable, and comprising a) from 15 to 95% by wt. of the reaction product of at least one metal cation of Group Ia and Group IIa elements of the Periodic Table with at least one aliphatic, monocarboxylic acid having 3 to 8 carbon atoms, and b) from about 5 to about 85% by wt. of a water absorbing, granular, edible material having a pH sufficiently high that the resulting pH of the mixture with a) is greater than about 6.5, the percentages of a) and b) being based on their total dry combined weight, and the particles contain-ing less than about 30% by weight of moisture.

Description

0~3 Description Feed Supplement for Ruminant Animals Technical Field This invention relates to compositions of matter containing certain Ralts of volatile fatty acids and a water-absorbing granular material. Such compositions are useful as feed supplements for ruminant animals.

Background Art There are numerous published articles reporting ~he differences in digestive processes of ruminant animals as compared with those of monogastric animals. Ruminant digestion is described in consider-able detail, for example, by D. C. Church in "Digestive Physiology and Nutrition of Ruminants",Vol. 1, published by D. C. Church, produced and dis-tributed by O.S.U.Book Stores, Inc., Corvallis,Oregon.
The ruminant animal lives on ingested forage consisting of large amounts of cellulose which it cannot digest directly. Instead of direct conversion of the forage, the ruminant animal has evolved a symbiotic relationship with micxoorganisms, consisting of a variety of bacteria and protozoa. The bacteria digest forage for their own survival and growth and the host ruminant animal later digests the micro-organisms and their by-products.
Just as the ruminant animal requires certain pre-formed nutrients for its growth, the microorganisms upon which it depends for cellulose digestion have their own requirements for essential nutrients. M. P.
Bryant and I. M. Robinson (~. Bacteriol. 1962, 84:605) studied the effect of certain compositions, including a mixture of acetic acid, isobutyric acid, valeric acid, isovaleric acid, and 2-methylbutyric acid on ~20~$3 essential nutrition for the growth of ruminant micro-organisms. Prominent among these micxobes are the cellulolytic organisms upon which the ruminant depends. While it has also been shown by others that not all of ~hese volatile fatty acids are required by all of the organisms, at least one is required ~y each of the 23 for which the combination was shown to provide essential nutrients and each one was essential for at least one of these same 23.
Volatile fatty acids (VFA) have been shown to be incorporated into the structure of these micro-organisms by conversion to characteristic lipids and amino acids, such as ethanolamine plasmalogen, valine, and isoleucine. Th~se acids are normally present in the rumen as a result of catabolism by the micro-organisms of amino acids derived from the protein in the diet of the ruminant animal. Diets high in good quality protein may contain a sufficient supply of carbon chain nutrients precursors for optimal growth of cellulolytic organisms on such diets. However, high-protein diets are expensive and utilize either feedstuffs alternatively convertible to use directly by man or feedstuffs grown on land suitable for the growth of human food crops. It would be desirable to reduce the amount of expensive good quality protein in ruminant feeds and still be able to efficiently utilize cellulose, a foodstuff not utilizable directly by man.
Ruminant nutritionists have shown that during the digestive process, in the rumen of cattle, bacteria break down feed protein to ammonia and fatty acids.
The bacteria then use the ammonia to synthesize cellular protein. These bacteria pass from the rumen to the abomasum and the intestine where they are digested and serve as the major source of protein for maintenance of body tissues and for milk production.

i3 Extensive ~tudies on the nu~rition of rumen bacteria have shown that fiber-dige ting ~acteria require cer-tain isoacids, such as isobutyric acid, as well as a~monia for synthesis of bacterial pro~ein. ( ~
Notes, Nov., 1973, p. 7, Dr. Robert M. Cook, Michigan State University publish~d by ~he Cooperative Extension Service.) Without isoacids, urea or NH3 cannot be utilized by these rumen bacteria. For man~
years cattle rations have been supplemented with non-protein-nitrogen in the form of urea or ammonia.
Patents of interest include U.S. Patents No.

2,154,449; 2,6B7,354, 3,441,539; 3,642,488: 3,934,041:

3,962,329 3,984,572 and 3,989,B46. Other patents of interest include U.S. Patent No. 3,564,098 which dis-closes a method of improving growth response inruminants which comprises or~lly administering certain acids, including valeric acid. Also, U.S. Patent No.
3,982,028 discloses that volatile fatty acids are absorbed through the rumen walls and are utilized by the animal as primary energy sources. The effects of isoacids (isobutyric, isovaleric, 2-methylbutyric and valeric) on milk production were reported in 1980 J. Dairy Sci. 63:1098-1103.
United States Pate.~t 4,376,790 relates to ammonium salts of certain ~ and 5 carbon atom volatile fatty acids and their use as ruminant feed.
Other publications of interest include Chem. Abs., Vol. 72, 1970, 19522e J. Bacteriol-826,605, 1962 pages 605-614; J. Bacteriol-83:523-532; and J.
Nutrition, 101:101-112.
It is therefore known that VFA with branched and straight chains ~re essential nutrients for growth of rumen cellulolytic microorganisms. VFA are utili~ed by the cellulolytic microorganisms as precursors for biosynthesi5 of fatty acids, amino acids, and other ~01~3 cellular constituents. It has been reported that supplementation with VFA in diets fo~ ruminant animals stimulated growth of many rumen microorganisms and increased the rate or exten~ of ruminal cellulose digestion and microbial protein synthesis, particularly when poor quality diets were fed. The beneficial effects obtained by supplementing branched-chain VFA in feeds include increased ~eed intake, increased nitrogen retention, increased micro-bial protein formation for ~he improvement of the protein nutrition to the host animal, and increased meat and milk production. However, in practice, VFA
suffer from some serious drawbacks. One of the major drawbacks is the obnoxious odor of the free acids which has made the handling of VFA very unpleasant for the farmers and the animal feed operators. Another major drawback is the corrosivity of volatile fatty acids which causes the apparatus in contact with it to be easily worn out and presents a hazard to the skin and eyes of human beings and animals.
It has been suggested that certain salts of VFA
are less corrosive and odorous than free acids, but as efficacious as VFA. German Patent No. DT-1965923 teaches that lower branched-chain volatile acids can be used in the form o sodium, potassium, magnesium, or calcium salts to stimulate ruminal microbial activity and to increase the appetite of the animals.
British Patent No. GB-1309863 discloses the use of a mixture of lower fatty acid sodium salts as a feed supplement for ruminants. The feed supplement des-cribed in this patent is either in the form of anaqueous solution or, after further processing, in the form of a dry powder. U.S. Patent No. 3,958,009 discloses the use of ammonium and potassium isobutyrate as a means for inhibiting the gxowth of ;3 , .

plant and animal pathogenic and nonpathoqenic micro~
organisms and the improvement in the rate of weight gain in animals which have been fed with these iso-butyrates. U.S. Patent No. 4,179,552 discloses a liquid composition comprising a C3~C8 carboxylic acid, and ion selected from NH4 , and cations of Group Ia and Group IIa elements according to the Periodic Table and water. The ratio of acid to cation is between 2:1 and 4:1 on a chemical equivalent 10 basis.
It is known that alkaline and alkaline earth metal salts of VFA are hygroscopic. In an open environment, these salts absorb mois~ure quickly at ambient condi-tions and undertake hydrolysis to generate a small amount of free VFA resulting in the characteristic unpleasant odor. Unless the dry salts are kept in a sealed container, it is very difficult to maintain the dry powder form of the salts and to prevent generation of odor at typical warm and humid stoxage and operat ing conditions of a farm or feed mill.
The above-mentioned patents have not addressed the problems of hydrolytic stability of the salts of VFA, and the odor caused by interaction of VFA salts and moisture at ambient conditions. Furthermore, these patents do not disclose a process of producing a solid, flowable, nonodorous product while still main-taining water in the finished product.

Disclosure of the Invention According to the present invention, homogeneous particles of material adapte~ to be orally administered to ruminants are provided. These particles are characterized by being solid, flowable, and hydrolytically stable. The particles comprise a) from about 15 to about 95% by wt. of the reaction product of at least one metal cation ~20~0~3 selected from the group consisting of Group Ia and Group IIa elemen~s of the Periodic Table with at least one aliphatic, mono-carboxylic acid having 3 to 8 carbon atoms, S and b) from about 5 ~o about 85~ by wt. of a water-absorbing, granular, edible material having a pH suf f iciently high that the resulting pH of the mixture with a) i5 greater than about 7.0-The percentages of a) and b) are based on their total dry combined weight. The particles contain less than about 30% by weight of moisture.
These particles are especially desirable for ruminant animal feed supplementation because of a number of reasons. The particles are solid and flow-able allowing them to be easily handled. ~eing metal salts of the volatile fatty acids, they do not have an objectionable odor, which is commonly found with the free acids as well as some of the other salts. Due to the presence of the water-absorbing edible material, the particles are hydrolytically stable, whereas with-out the presence of such material, the salts absorb enough water from the atmosph0re alone to become liquid or semi-solid- By providing a basic environ-ment, the water-absorbing material prevents the forma-tion of the free acids which would cause objectionable odor. Once ingested by a ruminant animal, the salts are broken down into the individual acids from which they are derived, allowing the animal to receive all the benefits from such acids described hereinbefore.
The metal cations used in reacting with the mono-carboxylic acid are selected from the Group la and Group IIa elements of the Periodic Table. Preferably, these cations are sodium, potassium, calcium or 1:~0~0$3 magnesium. Sodium and potassium are especially pre-ferred.
The aliphatic monocarboxylic acids having 3 to 8 carbon atoms used in reacting with the cations are preferably isobutyric, n-butyric, 2-methylbutyric, n-valeric and isovaleric, or a combination thereof.
Most desirably, the acids are a combination of iso-butyric, valeric, isovaleric and 2-methylbutyric.
The metal cation and acid are reacted in a manner well known in the art to form the salts. For example, sodium hydroxide may be mixed with a blend of the acids to form sodium salts.
The water-absorbing material used in this inven-tion is selected from basic water-absorbing minerals such as metal oxides, metal hydroxide, basic inorganic salts, clays, natural cellulosic and proteinaceous materials, synthetic polymeric materials such as poly-acrylamide and polyethylene glycol, and a combination of these materials. ~ combination of these materials which provides a wAter-absorbing capability and yields a saturated solution or dispersion with a pH of about 7~0 or above after absorbing a sufficient amount of watex is particularly useful in this invention.
Feed-grade minerals and natural cellulosic and proteinaceous materials which satisfy the above-mentioned properties are most prefexred in this invention. Typical examples are listed below.
Metal oxides such as magnesium oxide, calcium oxide, aluminum oxide, and silicon dioxide;
Metal hydr~xides such as magnesium hydroxide and calcium hydroxide;
Salts such as sodium carbonate, sodium bicarbonate, magne ium carbonate, calcium carbonate, rock phosphate, mono-, diand tricalcium phosphate, anhydrous calcium sulfate, anhydrous zinc sulfate, anhydrous calcium chloride;

1~0~ $3 Clay such as bentonite, kaolinite, talc and vermiculite;
Cellulosic materials such as bran, dehydrated alfalfa, vegetable gums, and dry hays.
The water-absorbing materials have a pH
sufficiently high that the resulting mixture with the reaction product of metal cation and acid has a pH of at least 7.0, preferably at least about 9.5. Thus, formation of free acid from moisture in the environ ~ent is minimized.
The salts can be prepared by reacting one or a blend of acids with an essentially stoichiometric amount of a base containing the desired cation in an aqueous medium.
A volatile fatty acid salt with an alkaline or alkaline earth cation is usually prepared by reacting the free acid and the respective metal oxide or hydroxide in an aqueous medium, and then evaporating water to obtain a dry powder product. Since one mole of water is generated in the neutralization reaction for each mole of free volatile fatty acid, the process of separating water from the reaction products in order to get a dry powder form of salt is unavoidable and usually energy- and time-consuming. Concentrated aqueous solutions of sodium hydroxide, or potassium hydroxide, about 50~ or above are preferred to be used in the reaction in order to minimize the total amount of water to be absorbed by water-absorbing carriers.
The feed composition according to this invention is then prepared by adding, while applying rigorous mix-ing, a desired amount of water-absorbing material to the aqueous medium until a solid, flowable product has formed. The amount of water in the product may be reduced by evaporation either before or after a~ding water-absorbing carriers. Preferably, the finished product prepared by this meth~d contains at least 25 ~0~3()$3 (by weight on dry basis) salts of VFA. The solid, flowable, VFA salts on carriers may be uæed as a feed supplement or mixed with pelleting aids or other feed ingredients to make a final product in pellet form.
The feed supplement is fed to ruminants in quantities sufficient to result in weight gain and increases in milk production. The reaction product of the metal cation and acids is broken down by the ruminant animal to the metal cation and acids. The quantity of feed supplement fed per day is determined so as to result in an in~ake of about 5 to about 150 grams of the acids.
The amount of VFA salts of Group I and Group II
cations required to result in these amounts of acids can be calculated using the ratio of the VFA molecular weight to the molecular weight of the VFA salt. Such stoichiometric calculations are well known to those skilled in the art. For example, to find the weight of acid to be derived from given weight of a VFA salt, the following equations apply:
I. Conversion Factor for Group Ia Elements Molecular Weight of VFA
(Molecular Weight of VFA-l) + Atomic ~t. of Group Ia Element II. Conversion Factor for Group IIa Elements 2(Molecular Weight of VFA) 2(Molecular Weight of VFA-l)(Atomic Wt. of Group IIa Element) Thus, for example, to find the equivalent weight of acid in the sodium salt of a mixture of C-4 and C-5 acids (31.5% isobutyric, 68.5% mix~ure of valeric, i~ovaleric and 2-methylbutyric), the following calculation is made:

~0~3 Equivalen~ VFA in Sodium VFA (from Formula I~
= M.W. of the acids (M.W. of the acids -1~ + atomic wt. of Sodium = 97.7 - 81.62%
g7.7 - 1 + 23 Therefore, for a ration of 5-lS0 grams acid per day, and for compositions containing about 15-95%
sodium salts, it is calculated that the weight of sodium salts fed per animal per day is between about 6 and about 1250 grams. Thus, the desired ration and the concentration of sodium salts in the composition will determine the quantity of composition to be fed.
The following examples are submitted for a better understanding of the invention.

This example illustrates the process, stoichio-metry, and reaction conditions for the preparation of a product disclosed herein.
An amount of 50~ aqueous fiolution of sodium hydroxide (32.8 grams) is added to a mixture of volatile fatty acids (40.0 grams) containing 31.5%
isobutyric acid and 68 ~ 5~ mixed C5-isoacids (n-valeric acid, isovaleric acid, and 2-methylbutyric acid) so as to neutralize the acids completely. It is observed that the temperature of the mixture rises very rapidly because of the exothermic neutralization seaction. The mixture is essentially colorless until the temperature reaches about 90C., above which an instantaneous yellowing of solution is observed. If the temperature of the mixture is lower than 80Co ~
the mixture gradually solidifies to a waxy solid and the reaction appeared to be incomplete. To ensure the completion of the neutralization reaction, the temperature of the reaction mass is raised to the range of 95-110C. by con~rolling the rate of addition ~0~0$;3~

of NaOH, and/or by supplying heat to the reaction mass until the yellowing of the ~olution is observed. A
quantity of bentonite (110 grams) is added to the yellow salt sol~tion, which contains 67.4~ salt and 32.6% water. The mass is thoroughly mixed and cooled to obtain a solid, granular, flowable, product with a mild pleasant odor which contains ~6.8% sodium salt of VFA on dry basis, 55.9% bentonite, and 18.2~ water.
When the salt solution is allowed to cool alone, it solidifies at about 60C. to a soft, waxy solid.

This example illustrates the use of a highly con-centrated NaOH solution in the process to ~inimize the amount of water-absorbing carrier in the finished product.
A solution of VFA sodium salt is prepared by reacting 100 grams of mixed volatile fatty acids (same VFA composition as in Example 1) with a stoichiometric amount of 73% aqueous solution of NaOH at 100C.
Seventy-five grams of magnesium oxide or bentonite is required to blend with the salt solution to obtain a granular, solid, flowable, mildly aromatic product.
The content of sodium VFA in the product is 53% by weight, which is substantially higher than the sodium VFA content in Example 1. When the hot solution is allowed to cool at an ambient condition, it solidifies at about 80C. to a waxy solid.

This example illustrates the hygroscopic nature of sodium VFA and the effect of basic inorganic water-absorbing minerals on odor quality of the product.
A stock solution of sodium VFA prepared as described in ~xample 1 is dried under reduced pressure in an oven at 110C. for 24 hours to yield a flaky, anhydrous, crystalline product. Four grams of anhydrOus sodium V~A is placed in a closed chamber at 100% relative humidity at 25C. Similarly, a 15-gram sample of a sodium VFA/bentonite product from Example 1 is placed in another chamber at 100~ relative humidi~y at 25C. After two days, anhydrous sodium VFA absorbed a sufficient amount of water to yield a clear solution. A faint obnoxious odor is detected when the chamber is opened. However, in the same period of time, sample from Example 1 became a mushy solid, but no detectable odor is sensed when the chamber is opened.

This example illustrates the use of three natural cellulosic materials as water-absorbing carriers for the preparation of a product disclosed in the inven-tion.
A stock solution of sodium VFA is prepared as described in Example 1. The stock solution contains 67~4% sodium VFA and 32.6% water. A sample of dry hay is chopped and ground cryogenically. Thirty grams of ground hay is added to a 30-gram solution of sodium VFA at 60C. The mixture is thoroughly mixed and allowed to cool to yield a solid, flowable, product with a mild, not unpleasant odor which contains 33.7 sodium VFA.
A sample of alfalfa pellets, commonly used as an animal feed ingredient, is ground to fine particles.
Thirty grams of ground alfalfa was added to a 30-gram solution of sodium VFA at 60C. The mixture is thorou~hly mixed to yield a solid, granular, non-odorous product which contains 33.7~ sodium VFA.
A similar product i5 also prepared by using wheat bran as the water-absorbing carrier at the same ratio as dry hay or alfalfa. Natural cellulosic materials ~2~

such as dry hay, dehydrated alfalfa, and bran absorb sodium VFA solution very quickly, but the products usually emit a different odor, although nonodious, but much stronger than the odor of the products using inorganic water-absorbing carriers such as magnesium oxide and bentonite.

This example illustrates $he use of a combination of water-absorbing basic inorganic materials and natural cellulosic materials as carriers for preparing a product in pellet form.
A sodium stock solutin is prepared as described in Example 1. An amount of sodium VFA solution is blended with an equal amount of a mixture of dehydrated alfalfa/bentonite ~1:1 by weight) to yield a soft, paste-like product. The product is nonodious and less odorous than products described in Example

4. The paste-like material i~ fabricated into cylindrical tablets with a diameter of about lJ4~3/8 of an inch and a length/diame~er ratio of about 1-2 by a Parr pellet press or spherical boluses with a dia-meter of about 1/4-3/8 of an inch by rolling and tumbling in a Hobart mixer. Soft pellets may be hardened by ~rying in air or in an oven. Dry, hard pellets are odor-free, easy to handle, and contain about 40% by weight sodium VFA.
The preceding portion of this specification has dealt with the preparation of a ruminant feed composi-tion which co~prises salts of aliphatic monocarboxylicacids having 3 to 8 carbon atoms and a moisture absorber. The function of the moisture absorbing basic matarial is described hereinbefore. It is known in the art that as the salts of the acids are fed to animals, they hydrolyze to the corresponding acid and base. See, for example, ~.S. Patent No. 3,708,578, 12~$3 column 1, lines 4~-S0. Thus, the alkali metal salts (e.g. sodium and/or potassium) of one or more of the acids are converted to the alkali metal and the free acid(s). Similarly, ammonium salts of the acids are converted to ammonia and the free acid(s). In each case, i~provement in performance such as milk produc-tion and weight gain is derived, at least to a large extent, from the acid(s), as described herein.
The results of efficacy feeding trials in dairy cows at three geographic locations using the composi-tions according to this invention are summarized below in Tables 1 and 2. Six combinations of ammonium iso-butyrate, ammonium isovalerate, ammonium valerate andammonium 2-me~hylbutyrate from which response surfaces could be computed, and a control are tested. Each treatment consists of 23 cows for a total of 161 cows in the experiment. The experimental period for each cow starts approximately 3-6 weeks prior to calving and include the ensuing lactation and dry periods.
Response surfaces of a surface fitting design, based on milk yield, defined an optimum blend compoced of 61 g of the 5-carbon salts plus 28 g ammonium iso-butyrate per cow per day. The optimum blend is very similar to the CP blend. The cows receiving the CP
blend peak at a higher level and produce significantly more milk than the control cows. In addition, the COW5 on the CP blend produce significantly more milk protein and solids-not-fat than the controls. The production of fat is higher in the CP ~reatment than the control but the difference is not significant.
The diference in total feed dry matter intake is smaller (and statistically not significant~ than the increase in milk production indica~ing a higher efficiency of feed utilization for the cows receiving the CP blend compared to the controls. There is no 1)$~

adverse blend effect on the health, reproduction, and body weight of the supplemented cows.
The responses are substantially similar in all trials suggesting that the conclusions of this experi- -ment are applicable to other locations.

Table 1 Milk Production, kg/cow/day Days From Average Percent Beginning of Number of Increase Standardization Days From Blend Blend Blend Blend Blend Blend CP Over PeriQd Calving Control _ A E B CP D CControl 21 36 31.0 31.1 30.9 31.9 33.~ 30.6 31.79.1 1 ~`
63 78 29.4 30.1 29.~ 31.0 32.4 29.9 31.010.4 1~5 12~ 27.8 28.9 28.5 29.4 30.9 28.5 29.611.3 1~7 162 26.2 27.3 2~.8 27.7 29.1 26.9 28.111.0 189 204 24.7 26.1 25.7 26.0 27.3 25.2 26.510.5 231 246 23.2 24.5 24.1 2~.2 25.5 23.5 25.110.1 253 ZS8 22.3 23.~ 23.3 23.3 24.6 22.5 24.39.9 ;
Table 2 Weight kg/cow Weight ControlBlend ABlend E Blend BBlend CP Blend D Blend C
Day 1 574 596 583 578 606 589 585 Day 105 585 602 584 595 605 612 59 Day 253 638 647 623 658 656 670 652 Weight gain 0-104 ll.0 2.5 2.2 17.0 6.3 22.8 13.6 Weight gain 0-250 64.7 47.7 47.1 79.7 57.6 80.7 67! 4 _l o 0~30$3 A small amount of animal feed flavors may also be incorporated into the product composition to mask any residual odor of VFA salts.
Unless otherwise indicated, all parts, percent-ages, ratios, etc., are by weight.
The invention has ~een described in detail wi~hparticular reference to preferred embodiments thereof, but it will be understood that variations and modii-cations can be effected within the spirit and scope of the invention.

Claims (13)

Claims

1. Particles of material adapted to be orally ad-ministered to ruminants, said particles character-ized by being solid, flowable, and hydrolytically stable, and comprising a) from 15 to 95% by wt. of the reaction product if at least one metal cation selected from the group consisting of Group Ia and Group IIa elements of the Periodic Table with at least one aliphatic, monocarboxylic acid having 3 to 8 carbon atoms, and b) from about 5 to about 85% by wt. of a gran-ular, edible material having a pH sufficiently high that the resulting pH of the mixture with a) is greater than about 7.0, the percentages of a) and b) being based on their total dry combined weight, and said particles con-taining less than about 30% by weight of moisture.

2. Particles of material according to Claim 1 wherein said metal cation is selected from the group con-sisting of sodium, potassium, calcium and mag-nesium.

Particles of material according to Claim 1 wherein said metal cation is sodium.

Particles of material according to Claim 1 wherein said aliphatic monocarboxylic acid is a mixture of

4 and 5 carbon atom acids.

5. Particles of material according to Claim 1 wherein said granular, edible material is water-absorbing.

6. Particles of material according to Claim 1 wherein said granular, edible material is selected from the group consisting of metal oxides, metal hydroxides, basic inorganic salts, clays, natural cellulosic and proteinaceous materials, synthetic polymeric materials.

7. Particles of material according to Claim 6 wherein the granular, edible material is bentonite.

8. Particles of material adapted to be orally administered to ruminants, said particles characterized by being solid, flowable, and hydro-lytically stable, and comprising a) from 15 to 95% by wt. of a mixture of sodium salts of isobutyric acid, valeric acid, iso-valeric acid and 2-methylbutyric acid, and b) from about 5 to about 85% by wt. of bentonite, the percentages of a) and b) being based on their total dry combined weight, and said particles con-taining less than about 30% by weight of mois-ture.

9. A feed for ruminant animals comprising the particles of Claim 1.

10. A feed for ruminant animals comprising the particles of Claim 2.

11. A feed for ruminant animals comprising the particles of Claim 4.

12. A feed for ruminant animals comprising the particles of Claim 6.

13. A feed for ruminant animals comprising the particles of Claim 8.