Soybean protein substitute for milk protein in milk replacers for suckling calves

Graduate Student Literature Review: The past and future of soy protein in calf nutrition

Our objective with this review is to encourage more research about the use of soy protein in young calf diets by learning from the mistakes of the past and acknowledging the promising results found when modern techniques are applied to treat soybeans. Total or partial substitution of milk proteins with soy proteins can represent a substantial increase in the economic efficiency of calf diets as long as it does not affect calf performance. Unfortunately, the results found in the literature indicate that the inclusion of soy protein in diets of young calves usually diminishes growth and health outcomes. The interaction of the antinutritional factors and antigenic proteins in soybeans with the gastrointestinal tract triggers a physiological response with negative consequences for the digestive tract and immune system of the calf. In this article, we highlight the importance of a correct processing method of soybeans by reviewing some of the published research that has evaluated different soy-based ingredients in diets for young calves. Conventional methods such as heating, ethanol extraction, and protein isolation can produce favorable results provided that the final product contains minimum or null amounts of antigenic and antinutritional factors. More recently, further processing methods such as microbial treatment of soybean meal reduces those antinutritional and antigenic factors, and can also increase the quality of soy protein by reducing the peptide size and by triggering the release of bioactive compounds. Experiments in which soy protein modified by this method was fed have increased in the scientific literature during the last decade due to the favorable results obtained in calves as well as in monogastric animals.

Detection and quantitation of pea and soy-derived proteins in calf milk replacers

Preruminant calves on several farms had diarrhea nonresponsive to treatment and were doing poorly, despite being fed a high quality calf milk replacer. Because these reconstituted milk replacers always had a sediment, they were suspected of containing insoluble nonmilk-derived proteins. Microscopic examination of the milk replacer, however, did not show any evidence of starch granules. We therefore analyzed the samples by SDS PAGE. We were able to identify and quantitate pea protein in calf milk replacers in which all the protein was supposedly milk-derived. We were also able to differentiate polypeptides derived from pea and soy. We concluded that PAGE is a sensitive technique for detecting nonmilk-derived proteins in calf milk replacers.

Soy protein concentrate and heated soy flours as protein sources in milk replacer for preruminant calves

Thirty-two male calves (8/treatment) in Trial 1 and 41 male and female calves (10 or 11/treatment) in Trial 2 were fed milk replacers containing 100% of the total protein from milk sources or 25% from milk and 75% from a soy product: soy protein concentrate; commercial heated (fully cooked) soy flour; or experimental soy flour for 6 wk. The experimental flour received moist heat sufficient to reduce trypsin inhibitor to 1 unit/mg. Calf performance improved with age on all diets. Growth, protein and dry matter digestibility, nitrogen retention, and morphology of the intestinal mucosa of calves on the all milk-protein diet were superior to those of calves on diets containing a soy product. All soy-fed groups had a humoral but no cell-mediated immune reaction to soy proteins. Soy protein concentrate and the experimental heated soy flour were superior to the commercial heated soy flour as protein sources for milk replacer.

Effect of protein source in calf milk replacers on morphology and absorptive ability of small intestine

Holstein calves were fed milk or one of four milk replacers with one-third of the total protein supplied by casein, soy protein concentrate, soy flour, or fish protein concentrate. The remainder of the protein in each replacer was from milk sources. Milk and milk replacers (13% solids) were fed at 10% of body weight daily. No dry feed or bedding was provided. Absorptive ability of small intestine was evaluated by xylose absorption test at 2-wk intervals. With calves under general anesthesia, a biopsy of small intestine was taken after each xylose test to examine morphological changes in mucosa by scanning electron microscopy. Villi were long, tapering, and uniform in calves fed milk. Calves fed casein had greater variation in size and conformation of villi. Gradual deterioration in villous integrity was seen in calves fed soy proteins. Calves fed fish protein concentrate performed poorly and had abnormal villi. Diets were changed to milk to test for reversal of effects after marked alterations in intestinal structure had been observed. Atrophy was reversed as villi returned toward normal size and shape within 2 wk after milk feeding began. The surgical procedure apparently did not cause harmful effects of villi. Absorption of xylose and daily gain were greater, and feces firmer, in calves fed milk than in those fed milk replacers.

Milk replacers for the neonatal calf

A rather long list of broad generalizations exist regarding milk replacers for calves. At least two more general statements should be added to that list. Most broad generalizations regarding milk replacers should be applied cautiously; and if young calves (less than 2 to 3 weeks) are to be fed milk substitutes, the products should be of high quality. Our primary goal in feeding baby calves should be health oriented--that is, not to pre-dispose to or cause diarrhea through diet. This means using milk-source ingredients in milk substitutes targeted for young calves. The preponderance of data presented in this article underscores that statement. Milk replacers containing nonmilk sources of major nutrients are better fed to older calves.

Performance and digestion by calves from limestone added to milk replacers containing soy protein concentrate

Sixteen male Holstein calves were fed milk replacers containing milk protein or 50% of the protein from soy protein concentrate for study of limestone as a buffer in the small intestine. Experimental diets were: A) 19% of crude protein as milk protein; B) same as A but containing .8% limestone; C) 19% crude protein, 9.5% milk protein, and 9.5% soy protein; and D) same as C but containing .8% limestone. Milk replacers were reconstituted with water to 14% solids and fed at 8, 9, 10, 11, 12, and 12% body weight from 1 to 6 wk of age. Calves were fed twice daily, and clean fresh water was available at all times. Soy protein concentrate in the replacer resulted in 20% lower weight gains, lower dry matter and protein digestibilities. Apparent crude protein retention also was reduced, but intake of nutrients, feed efficiencies, fecal scores, and rectal temperatures were not different between protein sources. Limestone did not change any of these measurements. Xylose absorption tests at 3 and 6 wk of age showed differences from age but not treatment. Analysis of digesta from different sections of the gut of 6-wk-old calves sacrificed 6 h after feeding revealed that pH throughout the small intestine was above 6 for both proteins, which may explain the ineffectiveness of added limestone. Compared to milk protein, soy protein concentrate produced a lower pH in the large intestine and feces.

Performance of young calves fed soybean protein replacers

In two 12-wk trials we evaluated soybean protein in calf milk replacers. In trial 1, twelve 5-day-old Holstein calves were allotted randomly to three milk replacers. The diets contained 26% crude protein. In trial 2, 18 calves were used and the diet contained 30% crude protein. In trial 1 period 1 (10 to 15 days), mean coefficients of apparent digestibility (%) for milk protein, soy protein concentrate, and full fat soy flour replacers were dry matter 92.0, 70.0, 71.0; protein 90.1, 56.6, 61.3; fat 88.9, 55.0, 53.2;; and ash 85.8, 62.5, 61.2. Average daily nitrogen retentions were 10.8, -1.24, and -.7 g. Results in period 2 (30 to 35 days) for digestibilities and nitrogen retention showed considerable improvement over those in period 1. In trial 2 period 1, mean coefficients of apparent digestibility (%) for milk protein, soy protein concentrate, and defatted soy flour replacers were dry matter 87.5, 66.6, 47.9; protein 80.5, 57.2, 28.5; fat 81.5, 55.9, 33.5; and ash 83.8, 58.9, 48.4. Average daily nitrogen retentions were 10.8, 2.9, and -3.6 g. Results in period 2 for digestibilities and nitrogen retention also showed considerable improvement. Calves are able to use soy based replacers more effectively with age.

Postprandial changes in the levels of lipids, glucose, urea and nonprotein nitrogen in the serum of veal calves fed milk replacers containing either skim milk powder or soybean protein concentrate

Postprandiale Veränderungen in der Serumkonzentration an Fetten, Glucose, Harnstoff und NPN bei Kälbern nach Zufuhr von Milchaustauschern mit Magermilchpulver oder Sojaproteinkonzentrat

Kälber im Alter von 7 Wochen (5–6 Tiere je Gruppe) erhielten Milchaustauscher mit Magermilchpulver oder Sojaproteinkonzentrat über 14 Wochen. Die Gewichtsentwicklung der Tiere zeigt bei der Magermilchgruppe eine höhere Tendenz.

Am Ende der Versuchsperiode wurden Blutproben kurz vor der Fütterung und etwa 3 Stunden nach der Fütterung genommen. Die Proteinquellen hatten keinen signifikanten Einfluß auf den Serumgehalt an Glucose, Harnstoff, NPN, Triglyceriden, Cholesterin und Phospholipiden vor der Fütterung. Ca. 3 Stunden nach der Aufnahme des Milchaustauschers mit Sojaproteinkonzentrat waren die Konzentrationen an NPN, Triglyceriden, Phospholipiden und Cholesterin erhöht. Die Unterschiede im Phospholipidgehalt und Cholesteringehalt waren signifikant. In der Magermilchgruppe war die Glucosekonzentration erhöht.

Die Erhöhung des Cholesteringehaltes wird auf die Freisetzung von Cholesterin bei der Umwandlung von HDL in LDL bei Sojaprotein‐Milchaustauscher zurückgeführt. Es wird vermutet, daß ein Teil der aufgezeigten postprandialen Veränderungen darauf beruhten, daß das Kasein im Gegensatz zum Sojaproteinkonzentrat im Abomasum des Kalbes koaguliert.

Effect of soy protein on calves' intestinal absorptive ability and morphology determined by scanning electron microscopy

Neonatal calves were fed whole milk (control) or one of three milk replacers with one-third of the total protein supplied by casein, Promocaf (a commercial soy protein concentrate), or an experimental soy flour. Xylose absorption was studied at 3 and 8 wk after a 12-h fast. Urine was collected for 5 h, and jugular blood was sampled at 0, 2.5, and 5 h after administration of xylose. Urinary excretions of xylose at 8 wk were 3.4, 5.3, 7.8, and 21.3% of xylose administered, respectively, for calves fed Promocaf, soy flour, casein, and milk. Increases in plasma xylose 2.5 h after administration were 7.7, 21.3, 31.8, and 46.5 mg/dl. Calves were sacrificed at 12 or 14 wk and duodenal tissues sampled for scanning electron microscopy. Micrographs revealed normal intestinal morphology with long, round, tapering villi when milk was fed. Casein feeding produced shorter, broader villi than did feeding whole milk. Abnormalities included absence of villi and short, blunted, convoluted villi on mucosal surfaces of calves fed soy proteins. Reduced surface area for intestinal absorption probably resulted from villous atrophy in calves with abnormal mucosae. Impairment of absorptive ability appears to be associated with morphological changes in intestinal structure.

Prediction of the suitability of soya-bean products for feeding to preruminant calves by an in-vitro immunochemical method

1. An immunochemical test for predicting the suitability of different soya-bean products for feeding to preruminant calves was studied. Calves fitted with abomasal and re-entrant ileal cannulas, were first given a series of feeds containing heated soya-bean flour and two with casein as the protein source, and then given further test feeds in which different experimental soya-bean products, prepared under conditions which might be used commercially, provided the nitrogren source. These products (Q, R, S and T) were prepared respectively by extracting fat-free soya-bean flour with aqueous ethanol at 960, 650, 650 and 550 ml/l and at 60, 60, 78 and 78° and then treating the residue with steam for 30 min.

2. After infusion of a test feed into the abmasum measurements were made of transit time through the small intestine, flow-rate of ileal digesta, recovery of polyethylene glycol (a water-soluble marker added to the feed) and net N absorption up to the distal ileum. Glycinin and β-conglycinin, antigenic constituents of soya-bean protein, were determined in saline (9 g sodium chloride/l) extracts of soya-bean products by haemagglutination inhibition assay.

3. After calves had been given a series of four feeds containing heated soya-bean flour, they showed hypersensitivity to the flour by developing disturbances in digesta movement and N uptake. When experiments were made to compare the effects of giving feeds based on casein with those containing products R, S and T it was shown that some differences in transit times and flow-rates of digesta through, and N absorption from, the small intestine occurred. Disturbances were, however, much less than those observed with product Q feeds.

4. Haemaggultination inhibition assay of products Q, R, S and T gave titres (log2 reciprocal of highest dilution of saline extract inhibiting agglutination) of 12, 5, 3 and 2 for glycinin and 13, 3, 3 and 2 for β-conglycinin respectively. After steam treatment only product Q gave measurable titres; 10 and 11 for glycinin and β-conglycinin respectively.

5. It is concluded that the haemagglutination inhibition assay is a suitable in vitro method of indicating whether soya-bean products given in liquid feeds to preruminant calves will cause gastrointestinal allergic reactions. Furthermore, results show that the removal of deleterious factors from soya-bean meal by treating with ethanol, is critically dependent on the proportion of water present in the ethanol and the temperature of the treatment.

The effect of giving feeds containing soya-bean meal treated or extracted with ethanol on digestive processes in the preruminant calf

1. Preruminant calves, fitted with abomasal and re-entrant ileal cannulas, were given, at intervals of 2–3 d by infusion into the absomasum, a series of five single experimental feeds containing heated soyabean flour (product B) as the only protein source. The calves were sensitized in this way to a constituent in the soya beans and by the fifth feed showed a number of digestive disturbances. Further test feeds were then given in which heated soya-bean flour was sometimes replaced by soya-bean products prepared under laboratory or commercial conditions by treating I part fat-free raw soya-bean meal with either I part (product M) or 4 parts (product L) ethanol (750 ml/l) at 78–80° and evaporating the whole mixture to dryness, or by extracting I part meal with 4 parts aqueous ethanol under similar conditions (product K). Products M, L and K were heated with steam and finely ground. Feeds prepared from casein and from commerical ethanol-extracted concentrate (product D) were also examined.

2. Measurements were made of transit time through the small intestine, flow rate of ileal digesta, recovery of polyethylene glycol (a water-soluble marker added to the feed) and net nitrogen absorption up to the distal ileum. Compared to feeds based on casein, feeds containing products K, L or M showed some differences in digesta movement and N uptake, but much less disturbance than feeds containing product B. Products prepared by extracting soya-bean meal with ethanol appeared to be slightly superior to those prepared from meal treated with ethanol, but the differences were not significant.

3. Weanling rats were used to assess the nutritive value of soya-bean products by an N balance method. Digestibilities (mean 0.948) and biological values (mean 0.860) obtained for products B, D, K and L did not differ significantly.

4. Results confirmed that extracting soya-bean meal with hot aqueous ethanol improved its value for calf feeding and indicated that at least part of the effect was due to the destruction of a toxic constituent present in the soya bean which probably acted by inducing a gastrointestinal allergy.

Amino acid supplementation of isolated soybean protein in milk replacers for preruminant lambs

The growth of preruminant calves and lambs fed on milk replacers containing vegetable proteins is generally inferior to that of preruminants given cows' milk. The inferior performance has variously been attributed to an amino acid imbalance, to heat damage in preparation, and to the presence of growth-retarding substances. Soybean products that have been treated to remove, or destroy, growth-retarding substances are now available commercially. An experimental design is described that has been used to determine the order of limiting amino acids in soy protein isolates, and which may also be used to estimate requirements for individual amino acids. The design allows an economy in time and in experimental animals, and gives results that are not significantly different from those determined in classical balance experiments.

The nutritive value of non-milk proteins for the preruminant calf. The effect of replacement of milk protein by soy-bean flour or fish-protein concentrate

1. Milk-substitute diets, in which 330-360 (L) or 610-700 (H) g/kg milk protein was replaced by protein from a thermo-alkali-treated soya-bean flour (SF) or from fish-protein concentrate (FPC), were compared in an experiment involving fifty Friesian calves, of which half were supplemented with a growth promoter, Grofas, known to have bacteriostatic properties. The liquid diets were fed ad lib. from 48 h of age until 136 kg live weight.

2. Seven calves, given non-milk protein, died or were removed from the experiment. There was little difference between treatments in the incidence of diarrhoea or in other observations on health of surviving calves, but those given non-milk protein maintained a lower mean rectal temperature.

3. Weight gain was reduced, especially during the first 3 weeks of life, by inclusion of non-milk protein. The reduction was greater for SF than for FPC, and greater at the H level. Supplementation with Grofas improved weight gain for calves given non-milk protein, but tended to reduce that for calves given milk protein.

4. Apparent digestibility of dry matter and protein was reduced when non-milk protein was used. The reduction was greatest at a young age, greater for SF than for FPC and greater at the H level. Apparent digestibility of fat was most markedly reduced with FPC, especially at 1 week of age, and was increased by Grofas supplementation. Digestibility of the carbohydrate in SF was low at 1 week but increased with age. Grofas supplementation caused a marked reduction in the disappearance of SF-carbohydrate in the alimentary tract. Apparent absorption of ash and calcium were reduced by non-milk protein, especially by FPC. The reduction in absorption of ash from SF was moderated by Grofas supplementation. Although Ca retention for calves given SF at the H level was very low, no bone defects were observed.

5. Nitrogen retention was slightly lower for calves given non-milk protein, but the efficiency of retention of apparently digested N was greater for calves given non-milk protein because of the much reduced urinary N excretion associated with a lower apparently digested N intake.

6. Dressed-carcass weight and ‘killing out’ percentage were lower for calves given non-milk protein, especially SF at the H level. Adrenal weights were markedly increased by feeding SF especially at the H level. Pancreas weight was greater for calves given SF than for those given FPC.

7. Weight of abomasal contents at slaughter was much lower for calves given non-milk protein. Weight of intestinal tissue and of total tissue in the alimentary tract were markedly increased by non-milk protein, especially by SF at the H level, and reduced by Grofas supplementation. The increased weight was associated with increased thickening of the walls of both the small and large intestine, which was possibly associated with hypertrophy of muscle cells.

8. It is concluded that up to 360 g/kg milk protein could be replaced by protein from this thermo-alkalitreated SF, and up to 610 g/kg milk protein from this FPC without markedly affecting performance, especially if an effective growth promoter is included in the diet. The beneficial effect of Grofas appeared to result from the reduction in the fermentation of the oligosaccharides of SF, which was reflected in higher digestibility particularly of fat and absorption of Ca and in reduced thickness of the intestines.

The effect of different diets including those containing soya-bean products, on digesta movement and water and nitrogen absorption in the small intestine of the pre-ruminant calf

1. Preruminant calves, fistulated in the abomassum and distal ileum, were given by infusion into the abomasum, at intervals of 2-3 d, single experimental feeds of cow's milk or a synthetic milk diet in which the protein source was casein or a soya-bean product. Polyethylene glycol (PEG) and phenol red were included as markers. 2. After infusion of the experimental feed, measurements were made of transit time from proximal duodenum to distal ileum and mean ileal flow-rates for the first 3 and 21 h after food residues reached the distal ileum. PEG recoveries for these two periods and net nitrogen absorption up to the distal ileum were also determined. In some experiments sodium, potassium and magnesium concentrations and numbers of viable bacteria in ileal digesta were determined. 3. Measurements of passage of digesta, recovery of marker and net N absorption did not differ greatly between calves given cow's milk and the synthetic milk diet containing casein. Compared to the casein-based diet, a diet based on heated soya-bean flour given to a calf for the first or second time produced a somewhat higher ileal flow-rate and a significantly lower net N absorption. Net N absorption was even lower when a calf received a diet containing unheated soya-bean flour. 4. Calves given the diet containing heated soya-bean flour on several occasions appeared to develop a sensitivity to the flour, and after further feeds containing it they had significantly higher rates of ileal flow (accompanied by correspondingly high rates of Na and K flow), lower small intestine transit times and lower net N absorption values than similarly fed unsensitized calves. They also had significantly lower rates of passage of marker in the first few hours after food residues reached the ileum, indicating inhibition of abomasal emptying. Over all, the changes indicated a severe disturbance in digestive function which was not caused by abnormal bacterial growth and may have been due to a gastrointestinal allergy. 5. Diets prepared from water-extracted flour and from soya-bean-protein isolate also led to digestive disturbances in sensitized calves, but those containing concentrates prepared by extracting soya-bean meal with hot aqueous ethanol did not.

The effect of different feeds, including those containing soya-bean products, on the passage of digesta from the abomasum of the preruminant calf

1. The effects of various factors on rates of flow and composition of digesta leaving the abomasum of preruminant calves were studied. The possible relation of some of these effects to the development of serum antibodies to certain dietary constituents has also been examined. Two situations were distinguished: (a) unsensitized responses, shown by calves receiving milk protein or soya-bean products for the first one or two occasions; (b) sensitized responses, shown by calves receiving certain soya-bean products, after a number of these feeds had been given. 2. For unsensitized calves, the rate of flow of total digesta from the abomasum was greater in the first few hours after a feed consisting of a mineral solution was given, than after cow's milk was given. This difference wasapparently due to differences in the composition of digesta entering the duodenum. Total digesta flows after giving synthetic milk feeds, prepared from different protein sources, were similar to those after cow's milk was given. 3. For sensitized calves, rates of flow of total digesta from the abomasum were greatly affected by the nature of the protein source used in the diet. Soya-bean flour (heated or unheated) generally caused inhibition of flow for some hours after feeding; a soya-bean protein isolate (isoelectric) had a similar but smaller effect, but a soya-bean concentrate (prepared by alcohol extraction of a soya-bean flour) and milk protein had little or no effect. The inhibition, believed to be a sign of more general disorders, appeared to be caused by a factor entering the duodenum which induced a change in the way in which the calf responded, probably as the result of a gastrointestinal allergy. 4. Calves given soya-bean flour or a soya-bean protein isolate (isoelectric) in their diets for several weeks, showed respectively high and low titres of serum antibodies to an antigen prepared from soya-bean flour. Calves given alcohol-extracted soya-bean concentrate had no similar antibodies. 5. In addition to variations in total digesta flow, dietary nitrogen compounds were held up in the abomasum to different extents after different feeds. After a whole-milk feed or a synthetic feed prepared from casein, a slow, steady release of N occurred over at least 9 h. N hold-up after giving soya-bean-containing feeds was slight for the soya-bean flour, but extremely marked for the soya-bean protein isolate (isoelectric). The latter hold-up was followed after several hours by a rapid outflow of N from the abomasum.

Concentrations of amino acids and urea in the plasma of the preruminant calf and estimation of the amino acid requirements

1. A study was made of factors affecting the plasma concentrations of free amino acids (PAA) and urea (PU) in calves receiving liquid diets. 2. When calves were given whole milk (approximately 0-05 kg/kg live weight) at 10.00 and 17.00 hours there were marked decreases in PAA and slight decreases in PU for about 3-4 h after the morning feed. Both PAA and PU thereafter increased slightly and then remained constant for the next 10 h. In subsequent comparative experiments samples were taken 3 h after the morning feed. The variation in plasma methionine, isoleucine, leucine, phenylalanine, tyrosine and total PAA was apparently greater between than within animals. 3. In calves transferred from a diet of whole milk to one consisting of diluted whole milk supplemented with appropriate nutrients, including amino acids, but deficient in methionine, PU increased markedly and plasma methionine decreased. 4. Two calves (50-60 kg live weight) given the latter diet supplemented to give an intake of more than 4-5 g L-methionine/d together with 0-3 g cystine/d showed marked increases in plasma methionine. This was considered to correspond with the point at which methionine requirements were met and that under these conditions the methionine requirement for these calves (mean value plus or minus SE) was 4-5 plus or minus 0-2 g/d. In the same two calves PU decreased markedly with increasing levels of methionine supplementation up to 3-9 g/d and the estimated methionine requirement (mean value plus or minus SE) was 3-9 plus or minus 0-4 g/d.