EP1662894A1

EP1662894A1 - Ruminants feed containing slowly digestible starch

Info

Publication number: EP1662894A1
Application number: EP03818627A
Authority: EP
Inventors: Thomas S. Winowiski; Otto Schade; Karl-Heinz SÜDEKUM
Original assignee: Borregaard Industries Ltd
Current assignee: Borregaard Industries Ltd
Priority date: 2003-09-18
Filing date: 2003-09-18
Publication date: 2006-06-07
Also published as: AU2003263439A1; WO2005025323A1

Abstract

A feed for ruminants is disclosed in which the starch component of cereal grain has been altered in such a way as to reduce its rate of digestibility by rumen microbes. This feed is produced by applying a reducing carbohydrate to comminuted cereal grain, heating the mixture, and then drying. The result of this treatment is to reduce the impact that feeding rapidly fermentable grains can have on rumen pH and fiber digestion, to provide a more even flow of fermentable starch to support microbial metabolism, and to increase the proportion of starch from fed cereal grain that is delivered to the small intestine.

Description

RUMINANTS FEED CONTAINING SLOWLY DIGESTIBLE STARCH

BACKGROUND OF THE INVENTION

[0001] The present invention is directed toward animal feeds, and more particularly to animal feeds for ruminants containing slowly digestible starch.

[0002] Feeder cattle and lactating dairy cows have a high energy demand and are often fed diets containing cereal grains. In the United States the primary cereal fed is corn while in other countries wheat and barley are more popular. Starch is the primary energy component in these grains and it is common to process grains to maximize starch utilization. Cereal grains may be ground, rolled, steam flaked, cracked or otherwise processed to render the starch components more available for digestion. However, these processes typically increase the ease with which rumen bacteria can ferment the starch. The presence of rapidly fermentable starch (RFS) can reduce rumen pH levels and depress fiber digestion.

[0003] I* ^{s an} unfortunate coincidence that high producing cattle have correspondingly high feed intakes and high ruminal passage rates. Digestibility depressions naturally results from increased ruminal passage rates and decreases in fiber digestion are responsible for a large proportion of the digestibility decrease. Reduced fiber digestion has two negative impacts. First, it lowers energy production, and second, it increases manure volume. Although a moderate depression in pH, to approximately 6.0, results in a small decrease in fiber digestion, any loss of digestibility under these circumstances can be hurtful. Further decreases in pH to 5.5 or 5.0 can result in decreased fibrolytic microbes and fiber digestion may be completely inhibited.

[0004] Several theories exist to explain the depressing effects of RFS. These include: (1) a preference by rumen microbes for RFS rather than fiber components; (2) a decrease in ruminal pH caused by rapid RES fermentation which prevents the fibrolytic microbes from attaching to their substrate; and (3) competition for essential nutrients resulting in preferential proliferation of RFS digesting microbes. Regardless, reduction in the rate of starch fermentation could have a positive impact on rumen function. Furthermore, if the rate of starch fermentation were reduced to such an extend that more of the starch was able to exit the rumen in an unfermented condition, its digestion and energy transfer might be accomplished more efficiently in the small intestine.

[0005] Several patents exist that describe the feeding of starch, cereals, or energy components and processes by which these feeds are prepared, U.S. Patent No. 5,686,125 discloses a feed for dry cows in which anionic salts are combined with a carrier and a binder, namely wheat and lignin sulfate, respectively. This mix is granulated by pelleting, which involves heating to 80°C for about one minute. This processing is not sufficient to reduce the susceptibility of wheat starch to fermentation by rumen microbes. The fact that this feed was specifically targeted to dry cows that do not require high-energy rations further indicates this mixture was not intended to and would not be expected to protect the starch component in the rumen.

[0006] U.S. Patent No. 5, 120,565 teaches preparation of a high-energy feed for dairy cattle by extrusion/cooking of a mixture containing lipid and at least 20% starch, preferably from corn or wheat. This method requires that the starch be finely ground and that it be gelatinized in the process. The main purpose of the invention is to provide a protective matrix to contain lipid that would otherwise interact with and interfere with the normal function of rumen microbes. Although this patent inadvertently suggests that extreme processing of starch can reduce its degradability by rumen microbes, there is no direct statement by the inventors that this is either true or that it would be desirable. Furthermore, Tothi reports (2003 Animal Feed Science and Technology 104:71-94) that extrusion cooking of corn actually increased the rate of starch disappearance in the rumen while extrusion of barley did not reduce its rate of starch fermentation.

[0007] U.S. Patent No. 5,789,001 teaches that processing of soybeans with lignin sulfonate to reduce the degradability of native protein by rumen microbes also reduces the disappearance of oil during incubation within the rumen. Although a variety of oilseeds are claimed in this method, practical experience has shown that protection of oil is most effective in soybeans where the protein to oil ratio is 2:1. As the ratio of protein to oil declines, the level of protection of the oil also decreases. Because of this trend, and the fact that cereal grains are relatively low in protein, it was not anticipated that treatment of grains with lignin sulfonate would protect significant quantities of nutrients other than the protein itself.

SUMMARY OF THE INVENTION [0008] The present invention provides a feed for ruminants in which the starch component of cereal grain has been altered in such a way as to reduce its rate of digestibility by rumen microbes. This feed is produced by mixing a reducing carbohydrate with comminuted cereal grain, heating the mixture to form a reaction product of the starch and the reducing carbohydrate, and then drying. The result of this treatment is to reduce the impact that feeding rapidly fermentable starch in cereal grains can have on rumen pH and fiber digestion, to provide a more even flow of fermentable starch to support microbial metabolism, and to increase the proportion of starch from cereal grains fed to ruminants that is ultimately delivered to the small intestine. [0009] Protection is achieved by non-enzymatic browning of the in situ starch material contained within the cereal grains. Preferably, the non-enzymatic browning is a principally reversible early or intermediate Maillard reaction. Non-enzymatic browning renders the starch material resistant to bacterial degradation by forming starch-sugar linkages in a protective matrix. The process comprises applying reducing sugars to cereal grains and heating to induce non-enzymatic browning. The process includes comminuting the cereal grain to insure penetration of the reducing sugars into the interior of the grain before the browning reaction is initiated. [00101 ^^ne P^resent invention thus provides a feed for ruminant animals which comprises a mixture of organic materials including a cereal grain containing at least one reaction product of in situ starch within the cereal grain and a reducing carbohydrate (sugar). The percentage of reducing carbohydrate on grain may be in the range of about 0.1% to about 6% by weight depending upon the cereal used and carbohydrate employed. The actual percentage of reducing carbohydrate on cereal depends on the particular carbohydrate or sugar used and on the starch itself with a more preferred dosage comprising about 0.5% to about 3% by weight while the most preferred dosage is about 1% to about 2% by weight. The cereal grain may be selected from those sources having sufficient starch for use in conventional ruminant feeds, and which include wheat, barley, oats, flour, triticale, maize (corn), sorghum, rice and rye.

[0011] The reducing carbohydrate comprises a reducing sugar selected from xylose, glucose, fructose, mannose, lactose, ribose, hemicellulose extracts and their hydrolysates, sugars contained in spent sulfite liquor, molasses and its hydrolysates and corn products and their hydrolysates, as well as mixtures of the above carbohydrates. Xylose is the preferred reducing carbohydrate. In a particularly preferred embodiment, however, the reducing carbohydrate is a component of spent sulfite liquor or dried spent sulfite liquor. Spent sulfite liquor typically includes about 10% to about 40% reducing carbohydrates as a component thereof. When employed in the present invention, the percentage of spent sulfite liquor solids on cereal grain is about 2% to about 40%. The spent sulfite liquor employed in the present invention is typically obtained from the pulping of hardwoods and/or softwoods.

[0012] The method of making a ruminant animal feed comprises the steps of selecting a desired cereal grain, comminuting the cereal grain by any means, such as by grinding, rolling, cracking, flaking or the like to fracture the seed coat, applying a reducing sugar to the comminuted cereal grain, allowing the sugar to penetrate into the interior of the grain, and thereafter heating the mixture at a temperature, pH and percent moisture for a time sufficient to cause non-enzymatic browning of the starch material in the cereal grain to form a protective matrix of starch-sugar linkages that are resistant to microbial attack in the rumen, but break down in the low pH conditions of the abomasum of the animal.

[0013] Comminuting may be accomplished in any conventional manner such as mechanically by a roller mill or a grinding mill, steam flaking, cracking or any other well-known method to fracture the seed coat.

[0014] Application of the sugar is preferably as a solution and may also be done in any conventional manner such as spraying, dripping, mixing or the like. Advantageously, steam is employed to cause the reducing sugar to penetrate the comminuted cereal grain. However, other methods resulting in sugar penetration may also be employed such as allowing a mixture of the sugar and cereal grain to steep, with or without heat, so that the sugar penetrates the interior of the grain and is positioned so that a sufficient amount of reducing sugar reaches the interior of the cereal grain to cause an early or intermediate Maillard reaction between the starch and the reducing carbohydrate.

[0015] Finally, the mixture is heated, preferably by steam, to result in non-enzymatic browning at a pH of from about 2 to about 10.5, a percent moisture from about 6% to about 40%, a temperature of from about 20°C to about 150°C, and for a time of from about 20 minutes to about 72 hours. Preferably, the steam not only causes the sugars to penetrate the grain but thereafter the steam results in maintenance of an appropriate amount of heat to cause non-enzymatic browning. It should also be understood that the cereal grain could be dried either before or after comminuting in order to enhance the penetration of the sugar into the interior of the grain.

[0016] The improved feed may be used as an additive in standard ruminant feeds, or may be substituted for part or all of the feed supplied to the animal. A particularly desired end result is to improve efficiency of milk production in dairy cows. Thus, increased milk production yields in dairy cows may be obtained with the same feed levels, or the same milk production yields may be obtained at reduced feed levels.

[0017] From the above, it can be understood that the feed of the present invention and its method of making and using it with ruminant animals have several advantageous. Cereal grains treated by this method exhibit a starch that is more slowly digestible in the rumen, which provides a more stable pH environment of fibrolytic bacteria. Furthermore, an increased proportion of the starch passes through the rumen intact which allows it to be digested in the small intestine. Post-rumen digestion is more efficient since the glucose can be absorbed directly into the blood stream through the intestinal wall. As a result, the starch is better utilized by the animal, and results in improved quantity of milk.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0018] The animal feed of the present invention includes cereal grains that contain a significant amount of starch that has been modified by non-enzymatic browning to form a reaction product of the starch and a reducing carbohydrate which results in a starch-sugar matrix that is resistant to microbial attack in the animal's rumen, but breaks down in the low pH conditions of the abomasum. In the preferred embodiment, the cereal grains used to form this feed are those found in high quality cereal grains such as wheat, barley, oats, flour, triticale, maize (corn), sorghum, rice and rye. [0019] The term "protection" refers to the reduced rate of digestibility of the starch- sugar reaction product in the rumen of the animal. This enables more of the "protected" starch to reach the abomasum. As noted above, this reaction product is the result of reacting reducing sugars (also referred to herein as reducing carbohydrates) with the starch in cereal grain to induce non-enzymatic browning to form the protective matrix. The term "reducing sugars" and/or "reducing carbohydrates" refers to sugars such as xylose, glucose, fructose, mannose, lactose, ribose, hemicellulose extracts and their hydrolysates, sugars contained in spent sulfite liquor, molasses and its hydrolysates and corn products and their hydrolysates, as well as mixtures of the above carbohydrates. Preferably, the reducing sugars used are those from economical sugar sources such as spent sulfite liquor which is a byproduct of some wood industries and a source of xylose, which is the preferred reducing sugar. However, mixtures of the above reducing sugars are appropriate and may be utilized herein.

[0020] The animal feed of the present invention may be used as an additive to supplement standard feeds fed to ruminants, or may be used to replace some or all of the standard feed itself. The term "standard feed" means the organic material found in feeds normally and conventionally fed to ruminants. Such feeds are well known in the art and include high quality protein feeds as well as other feeds of lesser protein quality. Such feeds include soybean meal, cottonseed meal, feather meal, blood meal, silages, meat and bone meal, sunflower seed meal, canola meal, peanut meal, safflower meal, linseed meal, sesame meal, early bloom legumes, fish products, byproduct protein feedstuffs like distillers and brewers grains, milk products, poultry products, maize (corn), wheat, alfalfa, barley, milo, sorghum, oats, flour, triticale, rice, rye and mixtures thereof.

[0021] The reaction products of reducing sugars and starches, i.e. termed non- enzymatic browning, herein means a condensation product obtained by reacting a starch useful in feeding ruminants and commonly found in standard ruminant feeds, and a reducing carbohydrate selected for its efficiency in reduction reaction with the starch. This reaction is well known in the art, and it is believed that the extent of the reaction forming the present feed corresponds to what has been described in the literature as early and/or intermediate Maillard reactions. These Maillard reactions are well known by those skilled in the art so that pH, temperature, moisture and time required to carry out the reaction to its optimum extent can readily be determined with little experimentation by those skilled in the art. Advantageously, the pH of the reaction is from about 2 to about 10.5. The temperature of the reaction ranges from about 20°C to about 150°C with 80 C to about lOO C preferred. The time of the reaction ranges from about 20 minutes to about 72 hours with 30 minutes to 120 minutes preferred, 40 minutes to 80 minutes more preferred, and 50 minutes to 60 minutes most preferred. The amount of moisture affects the reaction, and the percent moisture ranges from about 6% to about 40% with 15% to 25% preferred. [0022] The ruminant feed of the present invention may be prepared in several different ways utilizing different starches and different reducing carbohydrates as raw materials. In each case, a reaction takes place between the reducing carbohydrate and the starch to provide starch-sugar linkages in a protective matrix to thereby minimize the digestibility of the starch in the rumen yet permit ready digestion in the small intestine or abomasum of the animal.

[0023] The percentage of reducing carbohydrate on cereal grain ranges from about 0.1% to about 6% by weight depending upon the cereal grain and sugar employed. Preferably, an amount of about 0.5% to about 3% by weight is used, and most preferably an amount of about 1% to about 2% by weight is appropriate. The preferred source of reducing sugar is spent sulfite liquor. Spent sulfite liquor is that portion of the wood solublized in the acid sulfite pulping of hardwoods and/or softwood plant material. This well-known process is commonly used in making cellulose pulp for the manufacture of paper products. Spent sulfite liquors are comprised of about 40% to about 70% lignosulfonates, about 5% to about 30% reducing sugars, and about 2% to about 20% of oligosaccharides. Reducing sugars contained in spent sulfite liquor are typically a mixture comprised of glucose, mannose, xylose, galactose and arabinose. The relative proportions among the sugars vary depending upon the exact pulping conditions and the plant material used in the process.

[0024] The animal feed is prepared by first selecting the desired cereal grain or mixture of cereal grains, and then comminuting or breaking the grain cuticle by a mechanical process. For example, comminuting can be accomplished by grinding, rolling, flaking, cracking, breaking, or otherwise processing to open or fracture the grain cuticle or coat. Any method of comminuting the grain cuticle may be employed to render the starch components contained within the grain more available for reacting with the reducing sugars.

[0025] After comminuting, the grain is treated with a reducing carbohydrate by applying the sugar, preferably in solution, in any conventional manner to the exterior of the cereal grain. For example, the reducing carbohydrate may be applied by spraying the solution thereon, dripping the solution thereon, direct mixing of the ingredients, or other means. After the reducing sugar is applied to the cereal grain, the sugars in the mixture are caused to penetrate the interior of the grain. This can be accomplished with or without heat. If no heat is utilized, the mixture is typically allowed to steep anywhere from about 1 minute to 1 hour to insure penetration of the sugars into the interior of the grain.

[0026] Heat may also be utilized to cause the sugars to penetrate the cereal grain. If heat is employed, steam is preferred. Heating with steam causes a net migration of moisture from the surface of the cereal grain to its center which thus carries the sugar along with it into the interior of the cereal grain. This penetration of heat and sugar at the same time contributes to a more uniform non-enzymatic browning throughout the cereal grain. Thus, when the cereal grain is thereafter ground, as for example mastication by the animal, there is no loss in starch protection.

[0027] After sufficient penetration by the sugars, the cereal grain and reducing carbohydrate is heated at a temperature, pH, moisture level and time sufficient to cause non-enzymatic browning to produce the starch-sugar protective matrix. If steeping was employed, the mixture can be roasted with hot air or heated with steam. Likewise, if steam was employed to cause penetration of the sugars, heating with steam is thereafter maintained to result in non-enzymatic browning. Again, either roasting with hot air or heating with steam may be employed to cause non-enzymatic browning, but if steam was employed to cause penetration of the sugars, it is desirable to use steam as economically more efficient to result in non-enzymatic browning.

[0028] The cereal grains may optionally be dried before or after cracking. Typically, this is accomplished by heating with hot air. The advantage of drying the grain prior to application of the sugar solution is that dried grain will more readily absorb the sugars into the interior of the grain since the low moisture content of the grain tends to draw the sugar solution into its interior. However, drying increases production costs and thus is not essential to protecting the sugar in accordance with the present invention.

[0029] The amount of protected starch in a feed can be tailored to the situation, if desired. By tailoring the amount of heat, the particular reducing sugar used, and the cereal grain used, grains having different degrees of protection corresponding to different stages of the Maillard reaction may be provided. Thus, various end products can be manufactured and specifically tailored toward desired markets.

[0030] The efficacy of the present invention is illustrated by the following examples. Percentages specified in the following examples are on a weight basis and temperatures are provided in degrees centigrade, unless otherwise designated.

[0031] Example 1:

[0032] Coarsely ground wheat was split into identical batches of 200 g each. Four of these samples were treated with solutions containing various sugars such that approximately 15% water was added onto the wheat with the sugar. Following thorough mixing, the samples were placed in loosely covered jars and transferred to a 105°C oven for 90 or 150 minutes, depending on the expected reactivity of the sugar. The samples were then spread on paper to cool and dry overnight. Samples were tested for rumen undigested starch (RUS) by incubation in the rumen for 2, 4, and 16 hours, after which the residual starch was measured and reported as a percentage of the original starch placed in the bags. Treatment with xylose and lignin sulfonate, a byproduct material which contains approximately 15% xylose, doubled the amount of RUS at 16 hours. Treatment with glucose and lactose also slowed initial digestion and retained a higher level of starch after 16 hours.

Table A - Rumen Undigested Starch (RUS),% Rumen incubation time Treatment Oven time, min. 2 hr 4 hr 16 hr Untreated 0 22.0 16.2 6.8 2% xylose 90 65.9 56.9 35.2 2% glucose 150 66.6 57.9 34.1 5% lactose 150 56.3 46.4 24.4 5% lignin sulfonate 90 55.6 45.4 29.6

[0033] Example 2:

[0034] Various cereal grains were milled and split into two portions. One portion acted as the control while the second was treated to reduce starch digestion by rumen bacteria. In each case 4 grams of xylose were dissolved in 30 grams of water, which was then mixed into 200 grams of cereal grain. The mixture was transferred to a loosely covered jar and placed in a 105°C oven. After 90 minutes the meal was removed from the oven and spread on paper to cool and dry. Samples were tested for initial composition and starch residue remaining in a dacron bag following 4 hours of rumen incubation.

[0035] Results show that treatment reduced the amount of starch that was digested for every cereal tested; the greatest gains were in wheat and barley. Corn was slowly digested in the untreated sample, but treatment further reduced the loss. Oat starch, which was digested very rapidly, was also improved by treatment. Table B - Particle size analyses of ground cereal grains U.S. Sieve Wheat Wheat No. Fine Coarse Corn Barlev Oats Percent retained on each sieve 8 8.4 38.2 2.7 1.1 0 12 21.7 29.6 17.1 15 7.8 16 17.2 9.7 26.6 38.1 17.7 30 14 6.3 28.3 31.7 23.2 50 9.5 5.1 11.4 6.7 13.6 100 6.4 3.5 5.4 1.7 13.2 200 5.3 1.9 5.3 0.7 19.1 Pan 16.7 4.8 2.5 3.9 4.6 Table C - Effect of treatment on in situ digestion of cereal grains Rumen undigested Grain i Composition starch, 4 hr., % CP, % Starch, Xylose, Grain DM, % of DM % of DM Untreated 2% Wheat - fine 88.3 12.4 66.7 6.3 36.6 Wheat - coarse 89.4 11.7 60.5 25.0 54.0 Corn 90.4 8.9 64.4 80.2 83.7 Barley 89.5 12.4 61.1 18.0 37.4 Oats - fine 89.7 15.8 42.3 2.5 11.0

[0036] Example 3:

[0037] Ground wheat was split into two batches, the first being the control (Control) and the second being processed according to the invention (Test). Test wheat was combined with 5% lignin sulfonate (dry basis) and heated by direct addition of steam such that the temperature increased to about 105°C and moisture content increased to about 20%. This mixture was held at that temperature for 40 minutes. The mixture was then returned to ambient temperature by evaporative cooling under a stream of forced air. This cooling process also reduced the moisture content to below 15%. Samples were analyzed for nutrient composition (Table D).

Table p> _ Chemical composition Control Test Item Wheat Wheat Dry matter, % δδ.δ δδ.6 Composition of dry matter, %: Ash 1.0 2.5 Crude protein 13.4 14.8 Crude fiber 2.8 2.8 Starch 67.2 55.6 Neutral detergent fiber 14.2 21.1 Acid detergent fiber 3.2 4.0 Acid detergent lignin 1.4 1.5 Crude fat 0.9 1.0 [0038] The decrease in the initial level of starch in the Test Wheat is greater than can be explained by dilution of the lignin sulfonate. Starch determination was done by enzyme hydrolyses; it is possible that treatment with lignin sulfonate may impact hydrolyses of starch in vitro as well as in the rumen. The increase in neutral detergent fiber (NDF) sis an artifact of reduced protein solubility, again associated with treatment by lignin sulfonate. [0039] Digestibility of starch was then measured by incubation in the rumen for 2, 4, and 16 hours. Starch residue remaining in the dacron bags at the end of each period was reported as percentage undigested starch.

Table E - Rumen undigested starch, % Control Test Incubation time Wheat Wheat 2 hours 21 52 4 hours 16 49 16 hours 5 22

[0040] Example 4:

[0041] Quadruplicate samples of Control Wheat and Test Wheat from Example 3 were incubated in the rumens of three cannulated steers such that rumen bacteria would have free access to the samples and degradation products would flush through the 50 micron pores of the polyester bags that contained the materials. Incubation times were 2, 4, 8, 16, 24, 48, 72, and 336 hours. Following incubation the residue contained in the bags was analyzed for crude protein and starch. Degradation (DEG) of these components were calculated using Equation 1 (McDonald, 1981):

DEG = a + b ( 1 -e -*-D) for t > L (Eq. 1 )

[0042] Where: DEG = disappearance at time t corrected for small particles a = proportion of component soluble at initiation (t = 0) b = fraction of the component that is insoluble but degradable in the rumen c = a rate of disappearance of the fraction b t = time of incubation, and L = a lag phase.

[0043] Effective degradability (ED) was calculated using Equation 2 (McDonald, 1981): ED = a + (bc/(c + k))* e -*L (Eq. 2)

[0044] Where k is the estimated rate of outflow from the rumen and other parameters remain as described earlier. In this case an outflow rate of 8% per hour was used. Rumen undigestable protein (RUP) and rumen undigestable starch (RUS) was calculated as 100% minus ED. The invention resulted in doubling the level of both RUP and RUS (Table F).

Table F - Rumen undigested components RUP, % RUS, Control 28 18 Test 58 36

[0045] The substantial increase in RUS indicates that more starch will leave the rumen intact for subsequent digestion in the small intestine.

[0046] Example 5:

[0047] An experiment was conducted to evaluate the effects of treated wheat supplements on milk production in early lactation Holstein/Friesian cows. Comparisons were made between a negative control diet containing 3 kg of ground UK feed wheat (CW-UK) and test diets in which CW-UK was replaced by the same UK feed wheat treated with 5% lignin sulfonate (TW-UK) as well as German wheat treated with 5% lignin sulfonate (TW-D). In both cases treatment was made in a commercial feed mill as described in Example 3. A fourth treatment replaced CW-UK with ground maize as a positive control (CM) with slowly digested starch. Sixteen cows were balanced into four groups according to milk yield, parity, and live-weight. The experimental design was a 4 by 4 Latin-Square with four week feeding periods. Cows were supplied with grass silage ad libitum, 4.5 kg of 24% dairy concentrate twice daily at milking, and a single mid-day meal consisting of 3 kg of the test cereal grains. Feed intakes, milk yields, and milk components were measured during the last week of each period. Milk yield was lowest with the negative control, CW-UK. Milk yields with the treated wheats were similar to that of the positive CM control.

Table G _ Dγy matter intake and milk yield of cows fed various cereal grain treatments

Treatment CW-UK TW-UK TW-D CM Dry matter intake, kg/cow/day Silage intake 8.5 8.6 8.3 8.3 Milk yield Milk, L/cow/day 31.9 33.0 32.8 32.7 Fat yield, g/day 1152 1110 1174 1109 Fat yield, g/L 36.4 33.8 35.9 34.2 Protein yield, g/day 1001 1028 1029 1016 Protein yield, g/L 31.5 31.2 31.5 31.2

Cows fed UK treated wheat (TW-UK) had a significantly lower concentration of fat (33.8g/L) than those fed untreated UK wheat (CW-UK) or German Xylig treated wheat (36.4 and 35.9g/L, respectively). Cows fed the ground maize diet (CM) had a lower milk fat concentration, 34.2g/L, than those fed untreated UK wheat (CW-UK), with a milk fat content of 36.4g/L. It should also be noted that there was an improvement in milk yield of about 1 L/cow/day between untreated and treated feeds, which represents a significant increase in milk yield.

Claims

CLAIMS We claim: 1. A feed for ruminant animals, comprising a mixture of organic material including a cereal grain containing a reaction product of a reducing sugar and in situ starch within the cereal grain.

2. The feed of claim 1, wherein the reaction product is the result of at least one of early and intermediate Maillard reaction products.

3. The feed of claim 1, wherein said cereal grain is selected from the group consisting of wheat, barley, oats, flour, triticale, maize (corn), sorghum, rice, rye and mixtures thereof.

4. The feed of claim 1, wherein said reducing sugar is selected from the group consisting of xylose, glucose, fructose, mannose, lactose, ribose, hemicellulose extracts and their hydrolysates, sugars contained in spent sulfite liquor, molasses and its hydrolysates and corn products and their hydrolysates, and mixtures thereof.

5. The feed of claim 1, wherein said reducing sugar is xylose.

6. The feed of claim 1, wherein said reducing sugar is contained in spent sulfite liquor.

7. A method of making a ruminant feed comprising the steps of: providing a cereal grain which contains starch digestible by a ruminant animal; comminuting the cereal grain to expose its interior; applying a reducing sugar to said comminuted cereal grain to form a mixture; heating the mixture of reducing sugar and comminuted cereal grain at a temperature and for a time sufficient to cause non-enzymatic browning of the starch contained within the cereal grain to thereby render the starch resistant to rumen microbial degradation.

8. The method of claim 7 wherein after heating, the mixture is dried.

9. The method of claim 8 wherein after heating, the mixture is cooled prior to drying.

10. The method of claim 7 wherein the cereal grain is selected from the group consisting of wheat, barley, oats, flour, triticale, maize (com), sorghum, rice, rye and mixtures thereof.

11. The method of claim 7 wherein the step of comminuting comprises mechanically cracking the cereal grain.

12. The method of claim 7 wherein the step of comminuting comprises mechanically grinding the cereal grain.

13. The method of claim 7 wherein the step of comminuting comprises passing the cereal grain through a roller mill.

14. The method of claim 7 wherein said reducing sugar is selected from the group consisting of xylose, glucose, fructose, mannose, lactose, ribose, hemicellulose extracts and their hydrolysates, sugars contained in spent sulfite liquor, molasses and its hydrolysates and com products and their hydrolysates, and mixtures thereof.

15. The method of claim 7 wherein the step of heating occurs at a temperature of from about 20°C to about 150°C.

16. The method of claim 7 wherein the step of heating occurs at a pH of from about 2 to about 10.5.

17. The method of claim 7 wherein the step of heating is for a time of from about 20 minutes to about 72 hours.

18. The method of claim 7 wherein the step of heating occurs at a cereal grain moisture content of from about 6% to about 40%.

19. The method of claim 7 wherein the reducing sugar is in solution when applied to said comminuted cereal grain.

20. The method of claim 19 wherein the step of applying the reducing sugar to said comminuted cereal grain comprises spraying said solution onto said comminuted cereal grain.

21. The method of claim 7 further including the step of processing the reducing sugar and comminuted cereal grain mixture to cause penetration of the reducing sugar into the interior of the comminuted cereal grain.

22. The method of claim 21 wherein the step of processing the reducing sugar and comminuted cereal grain mixture comprises raising the temperature of the mixture above ambient.

23. The method of claim 22 wherein the step of raising the temperature of the mixture is accomplished with steam.

24. The method of claim 21 wherein processing the reducing sugar and comminuted cereal grain mixture comprises steeping the mixture.

25. The method of claim 24 wherein the step of steeping the mixture takes place at a temperature below the boiling point of the mixture.

26. The method of claim 7 further including the step of drying the cereal grain before comminuting the cereal grain.

27. The method of claim 7 further including the step of drying the cereal grain after comminuting the cereal grain but before applying the reducing sugar.

28. The method of claim 7 wherein said reducing sugar is xylose.

29. The method of claim 7 wherein said reducing sugar is contained in spent sulfite liquor.

30. The method of claim 7 wherein said mixture contains from about 0.1% to about 6% by weight of a reducing sugar.