CA1248404A - Animal feed supplement - Google Patents

Abstract

ANIMAL FEED SUPPLEMENT

Abstract of the Disclosure A method for maintaining animal digestive tract pH comprising adding trona to the animal diet at a rate which modulates normal pH reduction with feeding patterns of the animal. The trona is added to the animal feed mixture in particulate form.

Description

ANIMAL FEED SUPPLEMENT

This invention relates to an animal feed supplement, particularly, to sodium sesquicarbonate, a mixture comprised of sodium carbonate, sodium bicarbonate and water. It has been discovered that this mineral possesses buffering and neutralizing characteristics in the diets of animals, particularly ruminants.
It is known that buffers alter animal performance through effecting changes in digestive tract buffering capacity, pH and resulting nutrient flow.
Extensive studies have been conducted in the past, particularly in the past decade, on the effectiveness of buffers to counteract the negative effects of a high concentrate diet and sudden changes in diet for dairy cows and beef cattle. High energy intake in cattle is achieved by feeding large amounts of concentrates. The concentrates may often comprise up to 90% of the diet and can often result in some depression in milk fat percentage, a depression in feed intake, digestive upsets, and depressions in digestibility of major nutrients, especially starch.
The ruminant animal's existence is dependent upon the symbiotic well being of two ecosystems: rumen microorganisms and the host animal. The bacteria and protozoa that live in the rumen are capable of digesting cellulose, a component of the cell walls of stems and leaves of plants. The end products of microbially digested cellulose are utilized metabolically by the host animal.
The end products of the cellulose digestion by the microorganisms are the volatile fatty acids (VFA), i.e. acetic, propionic, butyric, valeric and small amounts of longer chain acids and isoacids. The slow degradation of cellulose to glucose, pyruvic acid and finally VFAs ,~

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results in a mixture of acids that is predominatly the lipogenic acids, i.e. acetic and butyric acids. While acetic and propionic acids may serve as precursors to the carbon portion of several metabolites, they are the precise building blocks of lipids, i.e. fats stored as adipose tissue and secreted in milk.
The gluconic acids such as propionic are more energy efficient. Once absorbed from the rumen, they are converted to glucose in the liver. The g]ucose is then metabolized in all tissues providing the energy necessary to do work, grow, gestate and lactate.
Economic pressures have forced the dairyman to maximize efficient utilization of costly feedstuffs by an expensive cow. This is accomplished by replacing a portion of the stems and leaves of forages with starch.
Starch is the predominant carbohydrate contained in the seeds and roots of plants. While starch i9 readily digested by animals, it is also digested in the rumen by rumen microorganisms. The end products of microbiologically digested starch are VFAs as with cellulose digestion. However, instead of a mixture consisting mostly of lipogenic acids, there is an increase in the quantity of glucogenic acids, i.e. propionic acids.
Starch feeding, therefore, provides the host animal with a mixture of VFAs which is metabolically more energy efficient for milk production. In addition, a larger quantity of VFAs are produced from a unit of starch than from cellulose as it exists in forages. The result is increased milk production.
A dietary regimen designed to increase milk production will alter the metabolic schemes of both the microorganisms and in animal tissues. As dietary starch is increased, the quantity and rate of VFA production are also increased. ~ormally, the free VFAs are at least partially neutralized in the rumen by the association with - ~L2~

sodium from sodium bicarbonate, the sodium bicarbonate having been produced by the animal and introduced to the rumen by the saliva.
Both the undissociated and dissociated VFAs are absorbed across the rumen wall against a concentration gradient. In the course of passing through the epithelial cells of the rumen wall, those acids previously dissociated now become undissociated before entering the blood flowing in the portal circulation. This neutralizing process requires bicarbonate.
The above neutralizing or buffering in the rumen and in the rumen epithelium is absolutely essential if the homeostasis in the animal is to be maintained and the animal is to live and produce. Therefore, when more VFAs are produced at any given moment, there must be a corresponding increase in buffering capability.
The predominant buffer involved in VFA
neutralizat;on by the host animal is sodium bicarbonate.
It is produced by the animal through combined pulmonary and renal functions. Since there are limits to respiratory rate and kidney function, sodium bicarbonate production by the host animal is also limited. Therefore, it has become common practice to provide additional buffer exogenously through the diet.
Diets with a low percentage of forage (low energy) result in less rumination and less saliva production than high forage diets. An analysis of the composition of saliva showed the presence of two buffers, bicarbonate and diphospha-te. The bicarbonate being present in greater concentration. A number of studies have suggested that the addition of sodium or potassium bicarbonate to high concentrate diets returns the rumen pH
to near normal levels. The sodium bicarbonate appears to increase rumen pH. Conventional feeding systems employ forage feed techniques which are supplemented with high concentrate feed rations. The conventional feeding system typically uses hay and pasture as forage which is usually supplemented with concentrate fed twice daily in the milking par]or or feed barn. By contrast, a complete ration feeding system employs a mixture of all feed components, blended thoroughly to prevent separation and sorting and offered free choice throughout the day. The twice daily feeding of large amounts of concentrate creates sharp disturbances in rumen fermentation characterized by large cyclic changes in pH and volatile fatty acid (VFA) production which may depress feed intake and induce digestive disorders. Digestive upsets are also common during dietary changes, particularly when cattle are transferred from high forage (high fiber) diets to high concentrate (high energy) rations. Dairy cows, for example, are usually transferred from high forage diets prepartum to high concentrate rations postpartum in a short period of time. Studies also indicate that several hours before parturition, rumen pH and bicarbonate concentration drop, which may be the result of diminished salivation, since rumination generally stops several hours prior to parturition. These studies indicate that the prepartum diet as well as the postpartum diet requires a buffer to alleviate the digestive upsets.
Whenever the buffering capacity is exceeded in the microbial environment of the rumen or in the systemic tissues of the animal, numerous undesirable metabolic reactions may occur. The accumulation of unbuffered (dissociated) VFAs in the rumen lowers the pH of the rumen fluid. Numerous chemical reactions requiring the action of numerous enzymes are involved in converting cellulose and starch to VFAs. Some of these enzymes are pH
sensitive. That is, they will not perform their normal catalytic function above or below a certain environmental pH. Metabolism stops in the sequence where the enzyme normaLly functions. The product which accumulates becomes the metabolic intermediate rather than the desired VFA.
For example, cellulose is an enzyme produced by the rumen bacteria and protozoa, and is essential in forming free glucose from beta linked glucose as it occurs in cellulose. Cellulose activity is destroyed at a pH less than 6.2. Therefore, without adequate rumen buffering, the cellulose contained in dietary forage will not be digested.
In the absence of suitable quantities of buffers, some species of rumen bacteria and protozoa may be destroyed. Lactic acid is a normal metabolic intermediate produced when glucose is converted to propionic acid. The particular microorganisms which produce lactic acid can survive in high acid (low pH) environments while those organisms that utilize lactic acid cannot. With lactic acid accumulation, the pH drops farther and eventually halts rumen activity. Excessive lactic acid accumulation in the blood and tissues can lead to kidney malfunction.
The desirability of providing ruminant animals with an exogenous source of buffering materials has been demonstrated. The feeding of sodium bicarbonate to ruminants has become standard practice in the dairy industry.
In the past decade, research of the buffering and neutralizing characteristics of various minerals and compounds has been intensified and buffers have been generally accepted in the animal feed industry to facilitate adaptation to rapid dietary changes immediately postpartum, to increase intake, to increase digestibility, to aid in the maintenance of acid-base balance, as well as to increase milk yield and composition. Compounds which neutralize as well as buffer also have value for high concentrate (high energy) feeding. Research indicates - 6 ~

that the neutralizing effectiveness of potassium carbonate compares very favorably in effectiveness to potassium bicarbonate and sodium bicarbonate in studies wlth lactating cows. Sodium carbonate has chemical properties similar to potassium carbonate and both compounds are alkaline in aqueous solution.
Trona, a naturally occurring sesquicarbonate mineral, is composed of about 35% sodium bicarbonate and 44% sodium carbonate, with calcium and magnesium carbonates the remaining primary ingredients. The studies of the present disclosure have found that trona is equal to or superior to sodium bicarbonate in its buffering/neutralizing capability. Sodium carbonate is a stronger neutralizer and expands the range of neutralization. Sodium carbonate immediately neutralizes, while sodium bicarbonate only buffers and can neutralize only within a range of pH. Furthermore, the s~udies show that while trona and sodium bicarbonate are similar overall for a high grain diet, trona produces a more stable pH especially shortly after feeding and during early morning hours, providing a more desirable long term environment for digestive activity. Trona has a substantial positive effect on maintaining a more stable digestive tract pH, especially in the upper portions of the digestive tract.
It is clear, therefore, that buffering minerals and compounds in this field of chemistry cannot be predicted from the prior knowledge of compounds which have been demonstrated to exhibit buffering characteristics.
Objects of this invention include providing a buffering compound which is effective in a variety of diets and rapid dietary changes and at concentrations within-the diet without effecting total feed intake. It is also an object of this invention to provide a buffer ~48404 compound to maintain a substantially stable digestive tract pH.
It has been discovered that the mineral trona meets the above objects and needs more nearly than previously known minerals and/or compounds. Experimental data shows that trona has a positive effect on maintaining a substan-tially stable digestive tract pH providing a more desirable long term environment for digestive activity.
Thus, according to one aspect of the invention there is provided an animal feed mixture including sodium sesqui-carbonate in particulate form as an ingredient of said animal feed mixture in an amount sufficient to maintain rumen pH within the range of 5.5 to 7Ø
According to another aspect of the invention there is provided a method for maintaining ruminant digestive tract pH, which comprises adding sodium sesquicarbonate to the ruminant diet at a rate and in an amount sufficient to maintain rumen pH within the range of 5.5 to 7Ø
According to another aspect of the invention there 2~ is provided a feed mixture for a ruminant animal including trona in particulate form as an ingredient of said feed mixture in an amount sufficient to maintain rumen pH
within the range of 5.5 to 7Ø
According to yet another aspect of the invention there is provided a method of regulating digestive tract pH of cattle, which comprises adding trona to the diet of the cattle at a rate and in an amount sufficient to maintain rumen pH within the range of 5.5 to 7Ø
The effectiveness of the present invention is illus-trated by the following results obtained in conducting studies to compare the acceptance of the mineral trona and its buffering/ neutralizing action to sodium bicarbonate or the absence of a buffer in diets for lactating dairy cows and beef cattle, the following experimental results being representative of the results obtained. The studies ~2~04 - 7a -demonstrate the effectiveness of the present invention in maintaining digestive tract pH and fermentative and digestive function.

EXPERIMENT ONE
In experiment one, thirty holstein cows which had calves without complications were assigned to one of three treatments one day postpartu~ in order of calving date.
The treatments were three complete rations with dry matter of 15% whole cotton seed, 30% corn silage, and 55% corn soybean meal concentrate mixtures. The concentrate mixture formulations are shown in Table 1, the first mixture including no buffer, the second mixture including 1.5~ by weight of sodium bicarbonate, and the third mixture including 1.5% by weight of trona.

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Treatment Number Ground Corn69.35 66.35 66.35 SBM 44 26.00 26.00 26.00 Defluorinated Phosphate 1.20 1.20 1.20 Limestone 2.65 2.65 2.65 Plain Salt .45 .45 .45 MgO .20 .20 .20 TM Premix .10 .10 .10 Vitamin A Premixa .05 .05 .05 NaHCO3-Corn Premixb -- 3.00 --Trona-Corn Premixb -- -- 3.00 TOTAL 100.00 100.00 100.00 20 a4.54 IU/ton.

bComposed of equal parts of buffer and ground corn.

The prepartum environment of all cows was uniform. Following parturition, the calf was permitted one feeding and then taken to a cow hutch. The cows were moved to the experimental cow lot which provided access to a free stall barn with at least one stall per cow and 30 water available continuously. At about 0800 and 2000 hours, the cows were brought into the nutrition barn where they received their rations ad libitum in individual stalls with mangers that permitted measurement of feed consumed. Water was available at each stall. Cows were continued on this regimen for seven weeks of lactation.

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Individual feed consumption was recorded daily.
Feed consumption was expressed as dry matter (DM) per hundred weight (CWT), DM per kilogram of metabolic body size and DM intake per unit of dairy merit, computed on a weekly average basis.
Feed DM intake per CWT of body size and per unit of metabolic body size are shown in Table 2. Differences among groups were inconsistent the first three weeks.
From weeks four through seven, the cows fed the diet with trona ate more feed DM than the cows fed the other two diets. The experimental data shows that cows fed the diet with trona sustained greater DM intake after week three when cows in early to mid lactation are switched abruptly to a high energy concentrate diet. Generally, lactating cows experience sharp reductions in body weight. This probably occurs because milk energy demands peak before feed energy intake. This lag in feed energy eaten postpartum is well recognized, but explanations for its occurrence or solutions to its presence are not known.
The experimental results shown in Table 2 indicate that cows fed a diet containing trona accept more feed earlier in the postpartum period than a diet containing no buffer or a diet containing sodium bicarbonate. This increase in feed intake may be attributable to the presence of sodium carbonate in trona which has stronger neutralizing power than sodium bicarbonate. Greater feed intake earlier in the postpartum period reduces the time and magnitude of negative energy balance and reduces the likelihood of ketosis.
Urine samples were obtained and pH was measured on days two, four, six and eight postpartum, and weekly thereafter. Rumen pH was taken immediately following urine sampling by stomach tube during weeks two, four and six. About one liter of the lnitial sample was discarded to reduce contamination by saliva. Rumen samples were - 10- ~2~a~4~

filtered through two layers of cheese cloth and stored at -5C. Volatile fatty acids (VFA) were determined by gas chromatograph. Body weights were taken weekly.

Treatment Week Mean ---- -- Dry feed/100 kg body weight ------10 Control 1.95 2.43 2.96 3.33 3.46 3.64 3.64 3.04 Sodium bicarb- 2.08 2.72 3.14 3.25 3.44 3.53 3.50 3.09 onate Trona 2.28 2.41 3.04 3.85 3.69 3.86 3.89 3.25 ~ ----- Dry feed/W kg ------_______ Control .090 .117 .142 .160 .167 .174 .175 .146 Sodium bicarb- .103 .135 .155 .160 .170 .175 .173 .153 20 onate Trona .110 .116 .146 .169 .179 .187 .188 .157 Rumen pH and VFA values are shown in Table 3.
Rumen pH is a reflection of diet composition and the quantity eaten. The higher the proportion of concentrate and the greater the amount eaten, the lower the pH, and thus the greater the acidity in the rumen. On the first day of postpartum, all cows in the experiment were switched abruptly from their dry cow d~et of high forage (grass, hay and concentrate) to a high energy diet of 55~
concentrate formulated for high milk production. The most critical -time for digestive upsets in cows is during the transition from the prepartum, high forage diet to the high concentrate (high energy) diet.

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In experlment one, a complete ration feeding system was used in whish all components are blended,and fed free choice. In this system, cows eat many small meals throughout the day and are less prone to digestive upsets and rumen aci~osis. The addi-tlon of buffers to high concentrate dairy diets often increases rumen pH and results in a higher molar percentage of acetic acid, a lower molar percentage of propionic acid with wider acetic to propionate ratio. The experimental results tabulated in Table 3 support this generalization. The data shows that a diet including trona as an additive has buffering and neutralizing properties which are greater than a diet containing no buffer or a diet containing sodium bicarbonate as an additive.
TABLE 3 - RUMEN pH

Average of Three Weeks Total AC/PR
Diet pH Acids Acetic Propionic Acetic Propionlc Ratio ------ mmol/ml ----------- ------ Molar % -------Control 6.58 73.9 39.1 27.4 53.1 36.7 1.49 Sodium 6.67 75.6 39.9 27.7 52.4 36.8 1.49 bicarb.
Trona 6.79 69.7 38.0 24.2 54.9 34.2 1.71 Urine pH data are shown in Table 4. For days two, four, six and eight postpartum a higher urine pH was observed for cows fed the two buffered diets. During the period of weeks two through seven, the urine pH average for the cows fed the diet including trona was greater than cows of the other two groups. While the mean pH values did not differ dramatically, this data is remarkable in view of the feed intake data shown in Table 2 which ~2~84~

distinctly shows a greater intake in the diet lncluding trona. As a generalization, the greater the feed intake, the lower the urine pH if the diet composition is held uniform, as it was in this experiment by the total mixed ration. In nearly all measurements of rumen and urine pH, the experimental data indicates that buffers are valuable in the diet of early postpartum cows. The data in Tables

3 and 4 indicates that cows fed the diet containing trona had average urine and rumen pH values greater than cows fed the diet containing sodium bicarbonate or the diet with no buffer.
TABLE 4 - URI~E pH

Days Postpartum Means Diets 2 4 6 8 --------------------pH---------------------Control 8.08 7.98 8.09 8.16 8.09 20 Sodium bicarbonate 8.29 8.43 8.30 8.33 8.34 Trona 8.15 8.28 8.27 8.31 8.25 Weeks -------------------pH--____________________ Control 8.48 8.26 8.17 8.07 8.09 8.18 8.22 Sodium bicarbonate 8.35 8.12 8.10 8.16 8.23 8.18 8.18 Trona 8.30 8.28 8.16 8.27 8.31 8.24 8.25 ~2~4~4 In experiment two, a study was conducted to determine the effectiveness of trona on digestive track function in beef cattle. Six multi-cannulated steers were assigned to individual pens. All steers were fed an adaptation diet consisting of 30% roughage and 70%
concentrate for a period of seven days. The steers were then fed assigned diets of either 50% roughage and 50%
concentrate or 10% roughage and 90% concentrate as shown in Table 5 during an ad~ustment period of seven days.
These diets included a control diet with no buffer, a diet including 1% by weight of sodium bicarbonate, and a diet including 1% by weight of trona. The steers were fed the same diet as in the adjustment period for the following six days and samples were collected during this period.
The steers were moved through the individual pens for six trials, each trial consisting of an adaptation, adjustment and collection period. All feeds fed and refusals were recorded daily.
Rumen volatile fatty acids (VFA) levels are shown in Table 5. Acetate levels were similar for cattle fed all diets and ranged from 29~4 to 36.3 mmol/liter.
Prop;onate levels differed significantly between diets, an average 16.5 and 11.5 mmol/liter for the high grain 10%
and 50% roughage diets, respectively. Butyrate levels were greater for the high grain 10~ roughage diet versus the 50% roughage diet. The total VFA level was similar for the high grain and roughage diets averaging 52.9 and 48.7 mmol/liter, respectively. The acetate/propionate ratio was lower for the high grain 10% roughage diet versus the 50% roughage diet, averaging 2.06 and 3.00 mmol/liter, respectively.
Arithmetically, for the steers consuming the 10%
roughage or beef diet, the trona fed group produced 2.41%
more total VFA than the bicarbonate fed group, and 11%

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more total VFA than the control group. For those animals fed the 50~ roughage or clairy d;et, the total VFA with both bicarbonate and trona buffers were increased 9.4~ and 10.5% respectively. Also significant is the acetate/propionate ratio in the 50% roughage or dairy diet, which increased from 2.63 in the bicarbonate fed group to 3.37 in the trona fed group. This increase in relative acetate production is important since acetate is the VFA most important in milk production. These results indicate that trona performs equal to or better than sodium bicarbonate in production of specific volatile fatty acids used in milk production.

Rumen Volatile Fatty Acids (mmol/liter) Beef DietDairy Diet Diet: 10% roughage50% roughage Buffer: None Bicarb Trona None Bicarb Trona SEM
Item Mo. obs. 6 6 6 6 6 6 Acetate29.432.2 34.0 32.5 34.7 36.3 2.5 Propionate 15.1 16.8 17.6 11.1 13.3 11.4 1.3 Butyrate5.2 5.0 3.5 2.2 2.0 2.8 .6 Total 49.7 53.9 55.2 45.7 50.0 50.5 3.5 Acetate/
propionate2.28 1.99 1.92 3.00 2.63 3.37 .21 The results of the feeding test on the di~estive tract pH are summarized in Table 6. Rumen pH was higher for the 50~ roughage diet than for the 10~ roughage high - 15 - ~2~0~

grain dlet. This was expected as high grain diets normally produce a more acidotic rumen. Both the sodium bicarbonate and trona increased rumen pH when cattle were fed the high grain diet. However, with the 50% roughage diet, the sodium bicarbonate had no effect on the pH and trona tended to increase the pH from 5.89 to 5.99. These responses indicate that sodium bicarbonate and trona were of equal effectiveness in elevating the depressed rumen pH
in cattle fed high grain diets. However, with the 50%
roughage diet, pH was already elevated and only trona was effective in modifyin~ the rumen pH.
Rumen pH also changed markedly with time reflecting feeding patterns and rumen fermentative activity. As was expected, rumen pH dropped greatly following feeding, this being the result of a large intake of feed and the activation of the digestive system. The pH drop after feeding was modulated slightly by sodium bicarbonate and was greatly reduced by trona, indicating that trona had a greater stabilizing effect on the rumen environment than did sodium bicarbonate, especially in cattle fed the mixed grain 50~ roughage diet where maintenance of a stable pH is essential to rumen fiber digestion. Rumen pH of cattle fed the control diet reached the lowest points at 0400 hours and at 1~00 to 2000 hours. At these same times, the rumen pH of cattle fed trona were much higher and near or above the overall daily average pH of cattle fed respective control diets.
This stabilizing effect of trona modulates surges in rumen fermentative and digestive activity, facilitating rumen feed stuff digestion.
The duodenal pH was low and in expected ranges for cattle fed the high grain 10% forage diet and the 50%
forage diet. The sodium bicarbonate buffer appears to have been of little or no effect on the duodenal pH.
Trona, however, increased the pH in cattle fed both the - 16 _ ~8~

high grain and high forage diets, providing a better environment for small intestinal enzymatic nutrient hydrolysis. As with the rumen, duodenal pH changed significantly over time reflecting feeding pa~terns, rumen fermentative activity and buffering capacity.
The ideal pH was at or near neutral and higher than the pH in any other digestive tract site. Diet significantly impacted the pH in the ileum with an average pH of 6.9 and 7.14 for cattle fed high grain or high roughage diets. While ideal pH tended to be higher when sodium bicarhonate or trona were included in the diet, these differences were not significant.
The fecal pH reflected the diet fed and was lower for the high grain diet than for the 50% forage diet. The fecal pH was in a normal range and indicates no significant effect of either the sodium bicarbonate or trona additive to the diet.

Buffer Effects on Digestive Tract pH
Diet: 10% roughage 50% roughage Buffer: None Bicarb Trona None Bicarb Trona SEM
Digestive tract site Rumen 5.54 5.61 5.61 5.89 5.89 5.99 .70 Duodenum 2.55 2.61 2.68 2.74 2.70 2.76 .33 Ileum 6.36 6.40 6.43 7.08 7.18 7.16 .89 Fecal 5.78 5.74 5.73 6.13 6.01 6.11 .72 ~;~48D~04 ~`
The foregoing studies indicate that trona has a substantial positive effect on maintaining a more stable digestive tract pH, especially in the upper portions of the digestive tract. In Figs. 1 and 2, the acid neutralization efficiency of trona versus sodium bicarbonate is plotted as a function of volume of acid (Fig. 1) and as a function of weight of reagent (Fig. 2).
The studies show that trona produces a more stable pH
especially shortly after feeding and during early morning hours, providing a more desirable long term environment for digestive activity.
While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims which follow.

Claims (6)

Claims:

1. An animal feed mixture including sodium sesquicarbonate in particulate form as an ingredient of said animal feed mixture in an amount sufficient to maintain rumen pH within the range of 5.5 to 7Ø

2. The composition of matter set forth in Claim 1 wherein said mixture includes 0.5 to 1.5% by weight sodium sesqui-carbonate.

3. The composition of matter of claim 1 wherein said mixture includes 1% by weight sodium sesquicarbonate.

4. A feed mixture for a ruminant animal including trona in particulate form as an ingredient of said feed mixture in an amount sufficient to maintain rumen pH within the range of 5.5 to 7Ø

5. The composition of matter set forth in Claim 4 wherein said feed mixture includes 0.5 to 1.5% by weight trona.

6. The composition of matter of Claim 4 wherein said feed mixture includes 1% by weight trona.