FEEDING OF BYPASS NUTRIENT TO DAIRY CATTLE FOR MORE MILK PRODUCTION

FEEDING OF BYPASS NUTRIENT TO DAIRY CATTLE FOR MORE MILK PRODUCTION

The term “Bypass Nutrient” refers to that fraction of the nutrients which gets fermented in the rumen to a comparatively low degree. It then becomes available at the lower part of the gastro-intestinal tract in the intact form for subsequent digestion and absorption. These slowly degradable proteins also have a function to provide the rumen microbes with a steady supply of nutrients, rather than with sudden bursts from easily soluble nutrients.

Protected nutrient technology: Protected nutrient technology is one such approach, involving feed management through passive rumen manipulation, by which the dietary nutrients (fat and protein) are protected from hydrolysis, allowing these nutrients to bypass rumen and get digested and then absorbed from the lower tract. The protected nutrients mainly include protected fat and protein and it is also called as bypass nutrients. The other protected nutrients are protected starch, chelated minerals and vitamins. Here, we can discuss only protected fat and protein and its impact of feeding on the performance of cows and buffaloes.

Protein, an important constituent in the ration of cattle and buffalo, when fed to ruminants is degraded by rumen microbes into ammonia, amino acid and peptides. Subsequently, these degradable products are utilised by the microbes for microbial protein synthesis, but that process may not be always efficient. Moreover, the excess ammonia produced from the degradation of highly degradable cakes, after absorption from the rumen wall is transported to the liver, converted to urea and excreted out through urine. It is a mere waste of dietary proteins, plus taxing the animal’s energy which is spent on urea synthesis. Although microbial protein is a good quality protein, it may not be sufficient to meet the requirement of high milk yielding animals. So ruminants may also be given proteins which are capable of escaping ruminal degradation, called undegraded dietary protein (UDP) or bypass protein, which is degraded in the intestines and absorbed as amino acids. Thus, to meet the nutritional requirements of high yielding animals, feed technologies like rumen-protected proteins can be adopted as it has consistently shown not only increased milk yield but also improved growth and reproduction. Protected nutrient technology is one such approach, involving feed management through passive rumen manipulation, by which the dietary nutrients (fat and protein) are protected from hydrolysis, allowing these nutrients to bypass the rumen and get digested and then absorbed from the lower tract.

These concepts were introduced in the early eighties, primarily to replace the conventional digestible crude protein system which has many limitations. They describe the protein quality of a feedstuff for ruminants, and the protein requirements based on rumen degradable protein (RDP) and undegradable dietary protein (UDP). Subsequently, the term has been extended to other nutrients like carbohydrates and fats that could also escape rumen fermentation partially, to be digested in and absorbed from the small intestines. The new approach envisages minimisation of ruminai fermentation losses, and better utilisation of the nutrients after their digestion and absorption from the small intestines.

 

THEORETICAL CONSIDERATIONS ABOUT SLOWLY DEGRADABLE NUTRIENTS

There are three type of nutrients that could bypass rumen fermentation to certain degree: protein/amino acids, starch/glucose, fats/fatty acids, Minerals (Zn, Cn, Mn) can be chelated, but in that form they entirely bypass the rumen, as they are stable at ruminai and abomasal pH. The slowly degradable or “bypass” nutrients may occur in feeds in their natural form, but feeds can also be manipulated to restrict their degradation in the rumen. Nutrients should be made resistant to microbial enzymes to such an extent so that rumen microorganisms get sufficient nutrients for efficient rumen functioning with respect to fibre digestion and microbial protein synthesis. The purpose of feeding “bypass” protein is that a large proportion of the protein is available directly at the lower part of gastro-intestinal tract, where it is digested and then absorbed as amino acids for utilisation at tissue level. Feeding of “bypass” starch reduces excess production of lactic acid in the rumen which would otherwise result in low rumen pH (acidosis), thereby affecting fibre digestion. Feeding of “bypass” fat (protected fat) is done primarily to avoid ruminai hydrolysis of bio-hydrogenation of unsaturated fatty acids and increasing energy density of feeds. The fats are thus digested mostly in the small intestines and absorbed as unsaturated fatty acids without affecting the fermentation of fibrous feeds in the rumen.

METHODS OF MAKING BYPASS NUTRIENTS

Some nutrients have bypass characteristics in their natural forms. However, others are required to be manipulated to reduce their rumen degradability for optimisations of ratios between degradable and undegradable nutrients in the diet.

Protection of proteins

The main methods available to protect proteins are the use of chemical reagents or heat treatment. In the past, formaldehyde was used (applied @ 1.2 g/100 g CP) to reduce the degradability of highly degradable proteins in rumen. However, its corrosive nature and possible carcinogenic effect had prevented it to be used as an agent for protection of proteins. Recently a group of Australian workers, however, have demonstrated that formaldehyde is metabolised to C02 and water after its absorption from intestines, thus reducing the fear for carcinogenic effects. Other technologies for inhibiting protein degradation in the rumen include the treatment with metal ions (ZnCl2 and ZnS04), coating with insoluble protein (blood, zein), acid and alkali treatment (NaOH, HCl, propionic acid), alcohol (ethanol) treatment and acetylation of peptides (acetic anhydride). But, to-date none of these have been commercialised. With regard to heat treatment, the temperature and the period of treatment is critical. If this combination is not proper, the protein is either under protected or over protected. Heat treatment of groundnut cake and soybean meal at 150°C for two hours seems to give sufficient protection. However, such a processing may not be economically feasible due to the high cost of equipment and energy. During the solvent extraction of oil cakes, the temperature reaches only 90-95 °C and the proteins are only partially protected at this temperature.

Protection of carbohydrates

Protection of starch can be achieved with formaldehyde treatment. Ammonia treatment could be another effective method to protect starch from ruminai hydrolysis. Treating starch with sodium carbonate plus sodium hexameta phosphate has been demonstrated to reduce starch degradation in the rumen.

Protection of fats

Lipids encapsulated by formaldehyde treated protein is an effective method of protection against ruminai hydrolysis and bio-hydrogenation of lipids, but due to the use of formaldehyde, the method has its limitation. During the refining of edible oils, free fatty acids are removed by treating with sodium hydroxide and then with acid. The free fatty acids thus removed by centrifugation are termed as acid oil which has roughly one-third the price of edible oils. These acid oils can be converted into calcium salts either by fusion or participation method. Thus, the fatty acids in the form of calcium salts are protected against the rumen enzymes, g method that can be commercially used for the protection of lipids.

NATURALLY OCCURRING BYPASS NUTRIENTS

In some feedstuffs, nutrients are naturally bound to other feed components, thus reducing their rumen degradability. The bonds with which the nutrients are linked remain intact in the neutral environment (pH = 6-7) of the rumen, but they are broken in the acidic environment of the abomasum (pH 2-3). These are referred to as naturally occurring bypass nutrients. Bypass protein values for some of the commonly used feedstuffs are given in Table 1. The feeds with higher bypass protein values are: cottonseed cake, maize gluten meal, coconut meal, fishmeal and leaf meals like Leucaena leucocephala (subabul). Similarly, the fermentation of starch from maize in the rumen is limited, thus, it is good source of bypass starch. With regard to fats, when fed through oilseeds, they are partially degradable in the rumen.

METHODS TO EVALUATE THE EXTENT OF PROTECTION

Whether the nutrients are naturally or artificially protected, there is a need to measure the extent of protection, i.e. the extent of degradation/hydrolysis in the rumen. For proteins, the rumen degradability by nylon bag technique is widely used. Values of effective degradability from different regions are available in India from published papers (Table 1). From these, the RDP and UDP values can be calculated for feeds. ARC (1984) and NRC (1985) have given the requirements for these two protein fractions in dietary protection for ruminants with respect to growth and milk production. For starch, limited work has been carried out so far. Those who have worked to measure the degree of protection, have done so by way of using labelled glucose and measuring glucose uptake at the intestinal level. With regard to fats, the percent of unsaponified or free fat can be found out by extraction with petroleum ether. The unsaponified fat gives degree of protection. The major problem in the measurement of degradation rate is that it indicates degradation for a given time. Since, it is not always clear how fast the feed passes the rumen, it remains difficult to estimate the actual fraction that leaves the rumen undegraded.

PRACTICAL IMPLICATIONS OF FEEDING BYPASS NUTRIENTS

Theoretically speaking, there appears to be good reasons to feed bypass nutrients for increased efficiency of nutrient utilisation by ruminants, especially at higher production levels. In practice, however, the animals’ response is quite variable. In the case of lactating ruminants, the response depends on several factors, such as: physiological status; stage of lactation; level of production; body condition score; availability of other nutrients. Responses are likely to be more favourable in high yielding animals in the early part of lactation or fast growing animals. These are typical situations where the demand for nutrients is high and where the animal may be in negative protein and energy balance with lower body condition score.

Feeding bypass protein

Generally, straws are poor in protein and minerals, but rich in cellwalls which are degraded in the rumen only through microbial fermentation. Feeding of slowly degrading nutrients along with straw provides ammonia and to some extent minerals which might improve fibre digestion.? The net result of feeding bypass protein could be the enhanced supply of amino acids from the intestines available for absorption and the overall improvement in the utilisation of dietary proteins. The achieved positive responses in gain, reproduction and milk yield to feeding bypass nutrients should be interpreted with caution. In many instances, much of the responses achieved could be explained to the supply of other nutrients (such as energy or critical minerals like P and S) rather than to the supply of bypass nutrients. This is more so when the basal diet is deficient or has limited supply of energy. Also, due to the slower release of nutrients in bypass feeds, the rumen function can be more stable.

Feeding bypass starch

Feeding of bypass starch can reduce excess production of lactic acid in rumen, which otherwise inhibits fibre digestion due to acidic pH condition in the rumen. Thus, starch which escapes rumen fermentation, is digested in the small intestines producing glucose, which after absorption is more efficiently used as energy source by the animals, compared to lactic/propionic acid absorbed from rumen.

Feeding bypass fats

Feeding of protected fats, mostly as calcium salts of fatty acids can increase milk yields and also the efficiency of energy utilisation in high yielding animals that receive diets of too low energy content. Although in many parts of India, the supply of energy feeds for ruminants is limited, normally it may not pose an acute problem because many cows are low yielders. However, it is difficult to meet the energy requirement of high yielding cows, especially in early lactation as the dry matter intake increases few weeks after the cows have attained peak yield. During 2 to 3 month high. yielding cows can be fed bypass fat. The minimum dietary fat level should be 3 percent in high yielding cows. However, in countries where animals are fed primarily on crop residues, feeding of bypass fat could help increasing milk production and growth. Inclusion of fats in the diet (more than 4-5%) generally causes disturbance in rumen fermentation, mainly through inhibition of fibre digestion. However, the inclusion of protected fats in ruminant diet can cause increase in the energy density of the diet without causing any reduction in fibre digestion in rumen. In developing countries, where cost of fatty acids (fat) is very high, acid oils can be converted into calcium salts and fed which are otherwise toxic to the rumen microflora. However, under those situations where feeding fat is not cost prohibitive and is to be fed more than 5 percent in the diet, fat can be again fed in the form of calcium salts without affecting ruminai fermentation.

BYPASS PROTEIN

By-pass is that protein which by-passes Rumen without degradation and is digested further in the digestive tract. This protein enhances milk production. The level of By-pass protein is high in some feed ingredients such as cotton seed cake, and soya meal but is less in other protein sources such as mustard cake. Milk producing animals have 4 chambers in their stomach for digestion. The first chamber has a storage capacity of 50 to 60 Litre, where straw & fodder get fermented, This chamber is called rumen. There is an immense amount of bacteria in rumen, these bacteria help in digesting straw & fodder, but when we give the animal a protein meal, bacteria turns 60% to 70% of protein into ammonia & this ammonia turns into urea in the liver, which excretes of the body through urine. So, the whole protein meal which is essential for the animal is wasted. But if we give appropriate chemical treatment to the protein meal, then the bacteria present in the rumen can’t break the meal & it will be well absorbed and digested in the lower part of the stomach. This method of processing protein meal is called BYPASS PROTEIN TECHNIQUE. The bypass protein supplementation provides amino acid which is absorbed by the small intestine, this increases the milk production of milch animals.

Protein is usually the first limiting nutrient for cattle and buffaloes fed low-quality forages. All ruminants derive their protein requirement from two sources. One is rumen un-degraded feed protein that gets enzymatically digested in the abomasums and small intestine and another source of protein is rumen microbes. The microbial fermentation of soluble protein in the rumen is an unavoidable consequence of digestion and under many circumstances; it is a wasteful process because high-quality proteins are broken down to ammonia, excess converted to urea in the liver and excreted through urine. The solubility of proteins change when subjected to special chemical treatment, the advantage of which is to protect good quality proteins from rumen degradation. A number of chemicals like acetaldehyde, formaldehyde, glutaraldehyde, ethanol, tannic acid, acetic acid, sodium hydroxide, etc. have been tried to protect proteins. Amongst all, aldehyde suggested for protection of protein, formaldehyde has been extensively used for production of bypass protein feed.

Usually, protein meals are fed to ruminants in India, which have variable degree of naturally rumen protected proteins. Protein meals, particularly rumen escape proteins, play a very important role as an excellent protein supplement, in livestock feeding. When these meals are fed as such to ruminants, about 70 per cent of the protein is broken down to ammonia by the rumen microbes in the rumen and a significant portion is converted to urea in liver and excreted in the form of urea through urine. However, if these protein meals are subjected to suitable chemical treatment, then their efficiency of utilization can be significantly improved. When chemically treated protein meals replace untreated ones, then due to less degradability of the protein in the rumen, excessive loss of both nitrogen and energy could be avoided, resulting in an increased energy and nitrogen balance, leading to increase in milk yield and milk constituents. Bypass protein feed is a new generation cattle feed in India and is manufactured by a special chemical treatment, developed by the National Dairy Development Board (NDDB). Bypass protein feed contains a large percentage of solvent extracted protein meals in treated form, grain by-products, whole grains, molasses, minerals and vitamins. The special feature of the formulation is that more than 70 per cent of the total protein in the feed is rumen undegradable protein.

The protection of protein can be achieved by various methods. Few of them are the following:

Naturally Protected Proteins: The protein degradability data (in the rumen) obtained by several groups of workers on a large number of feedstuffs in India and other countries has revealed that only a few feeds are good sources of naturally occurring protected protein (having lower protein degradability), viz., maize gluten meal, cottonseed cake, fish meal, coconut cake and maize grain. Feeds like linseed cake, deoiled rice bran, soybean meal and Leucocaenea leaf meal are of medium protein degradability; while Mustard Cake (MC) and Groundnut Cake (GNC) are highly degradable cakes.  Negi et al. (1989) found that 50 to 70% of total N in tree forages may be present as protected protein. However, these forages contain 16-53% of total N in the form of acid detergent insoluble nitrogen. This is because of the presence of tannins, particularly the condensed tannins which bind the proteins irreversibly and if fed to animals, are capable of corroding the epithelial lining of the gastrointestinal tract. So, tree forages could be used as a source of protected protein only after devising a method for their tannin detoxification, using either some chemical, biological or biotechnological approach. While the proteins of lower protein degradability do not need any protection, highly degradable cakes like MC, GNC and sunflower seed cake need protection against the attack of ruminal proteolytic enzymes, for improving their utilization by ruminants.

Heat Treatment: 

Heat treatment to feedstuffs has been found to increase protein protection (Senger and Mudgal, 1982). It works on the principle that heat treatment causes denaturation of proteins which provides effective protection against microbial attack. Heat treatment at higher temperatures reduces the availability of some amino acids like cysteine, arginine so to reduce such losses, steam treatment has been found fruitful. Steam treatment increases both bypassability and digestibility of proteins. Heat treatment at 125- 150⁰C for 2-4 hours could protect proteins very efficiently. High-pressure steam treatment with extrusion has shown promising results.

Formaldehyde Treatment: Proteins are chemically protected by treating with substances like tannins, formaldehyde, glutaraldehyde, glyoxal and hexamethylenetetramine. But formaldehyde treatment is most commonly used. Formaldehyde treatment has been found effective in improving the bypass protein (Walli et al., 1980) in oilseed meals, hay and silage. 0.5-1.5, 1-3 and 3-5% formaldehyde is used for protein protection in concentrates, hay and silage respectively. Formaldehyde treatment not only increases the rumen undegradable protein in feedstuffs but also increases its acceptability by animals.

Encapsulation of Proteins: Encapsulation of Proteins is usually done for good Biological value proteins and for inpidual amino acids. Methionine and lysine are limiting amino acids in microbial proteins on feed intake, plasma amino acids and milk production. So they can be given the form of the capsule with a combination of fats or fatty acids sometimes by addition of carbonate, kaolin, lecithin, glucose etc.

Amino Acids Analogs: Structural manipulation of amino acids to create resistance to ruminal degradation is another potential method for rumen bypass of amino acids. In addition to being absorbable from the small intestine, the analogue must have biological potency in metabolism by tissue. Analogues such as Methionine hydroxy, N-acetyl-DL-Methionine, DLHomocysteine thiolactone-Hcl, DL-Homocysteine, etc. have given satisfactory results. Reacting amino acids to produce imides, produced materials which survival ruminal conditions, yielded free amino acids at abomasal pH, and increased amino acids concentration in the ruminants.   

Feed Processing 

The normal procedure in the manufacture of feed ingredients can influence the magnitude of protein degradation in the rumen. Certain grain processing can either increase or decrease rumen degradation of Proteins. Increased ruminal degradation may be the result of disruption of the protein matrix, whereas heat applied or generated during grain processing can decrease ruminal degradation of proteins.

Metal Amino Acid Complex 

Metal complexes commonly available such as Zinc Methionine, Zinc Lysine, Copper Lysine, Manganese Methionine, Iron Methionine etc. their usefulness lies in the fact to assume that they must be stable in the rumen environment and abomasum and be delivered to the small intestine intact, secondly, there is some evidence that mineral chelates are considerably better absorbed than inorganic forms.

Beneficial Effects of Bypass Proteins

• Increase the supply of limiting amino acids like lysine and methionine to the small intestine.
• Improvement in milk production.
• Increase in availability of essential amino acids per unit of feed.
• Increase efficiency of utilization of proteins.
• Judicious utilization of protein meals, available in limited quantity.
• Improvement in fat and SNF per cent of milk.
• Better growth in young animals.
• Easier to meet the requirement of high yielding animals in an efficient way.
• Improvement in reproduction efficiency.
• Better resistance against diseases.
• Helps in increasing the net daily income of farmer’s.
• Helps to control Salmonella and reduce mould growth in feedstuffs.

 

NB-The process or treatment to protect dietary protein from degradation in rumen is known as bypass protein technology. These protected meals are digested more efficiently in the small intestine and results in extra protein being available for milk production. This helps the animal to produce more milk and of optimum quality.

• Bypass protein is also called rumen escape or undegradable protein. It is the portion of the protein from a feedstuff (corn, soybean meal, blood meal, etc.) that escapes from being broken down or digested in the rumen by microbes (bacteria, protozoa, etc.).
• Rumen bypass or “protected” fats are essentially dry fats processed to be easily handled and mixed into all animal feeds. Because dry fats naturally have high melting points, they are mostly insoluble at rumen body temperature.
• Protected nutrient technology is one such approach, involving feed management through passive rumen manipulation, by which the dietary nutrients (fat and protein) are protected from hydrolysis, allowing these nutrients to bypass rumen and get digested
• Bypass protein feed is a new generation cattle feed in India and is manufactured by a special chemical treatment
• Rumen degradable protein (RDP) deficiency can limit microbial growth, especially when diets containing high concentrations of rumen undegradable protein (RUP) are provided
  16.Protein can be divided in two parts, for the ruminant animals, in most of the feed, major part is degradable in rumen ‘Rumen Degradable Protein’ (RDP) and a small but variable amount of dietary protein escape rumen degradation ‘ Un-degradable Dietary Protein (UDP). UDP which enters the lower tract is absorbed mostly as amino acids following enzymatic digestion. Of the RDP fraction, substantial part is utilized as the N source for rumen microbes, for protein synthesis, while the rest is absorbed as ammonia. Only part of absorbed ammonia is recycled back to rumen as urea via saliva, the rest excreted out through urine.
• Bypass protein feed contains a large percentage of solvent extracted protein meals in treated form, grain by-products, whole grains, molasses, minerals and vitamins. The special feature of the formulation is that more than 70 per cent of the total protein in the feed is rumen
  undegradable protein.
• Standardized and commercialized bypass protein technology, use locally available protein meals such as rapeseed meal, sunflower meal, groundnut meal, guar meal and soybean meal.

Methods for protection of proteins in highly degradable cakes:

There are two ways to protect the proteins in highly degradable cakes in the rumen, and to convert these into Bypass Protein.

Heat Treatment: Heat treatment of oil cakes can be done through roasting at 140 degrees C for 30 minutes. It was found that the above time/temperature combination was quite sufficient to protect soybean cake protein, having protected its protein from rumen degradation up to 70-80 %. However, the problem with this method is that it is not a cost-effective technology.

Formaldehyde (HCHO) Treatment: 

Groundnut Cake was subjected to HCHO treatment using different levels of formaldehyde, viz. 0.5, 0.8, 1.0, 1.2, and 1.5 g HCHO/100 g cake protein. The protein degradability in the rumen was measured by in vivo Dacron bag technique. It was observed that the level of 1.0 g HCHO/100g of cake protein caused 70-80 % protection of its protein in the rumen. Accordingly, this level was considered as the optimum level of HCHO for protecting proteins from highly degradable cakes. Formalin is easily available in the market in liquid form. It is 40% HCHO, and accordingly, 2.5 ml of Formalin shall provide 1 g of HCHO. Formalin is a cheap chemical, thus making HCHO treatment quite a very cheap method of protein protection for making it a Bypass protein. However, at the time of Formalin application, precautions have to be observed due to its volatile and corrosive nature.

Results of the Growth trial on feeding Bypass Protein

Growth trials on goat kids fed two types of Cakes treated with HCHO:

A growth trial was conducted on 12 goat kids divided into 2 groups fed untreated or HCHO treated GN Cake (60% BPP in concentrate) for 3 months. At the end of the trial, it was found that it gave 30-35% increase in growth rate in the treated group over the control group.  The feed conversion efficiency was found to be much higher in the treated group.
Similarly, in another trial conducted on 14 goat kid, the animals were divided into 2 groups and fed either untreated or HCHO treated mustard Cake (60% BPP in concentrate) for a period of 3 months. The result in this experiment too was similar as observed in kids fed HCHO G.N. cake There was a 30-35% increase in growth in the treated group over the control group. Feed conversion efficiency too was much higher in the treated group as in the first case.

Growth trial on buffalo calves fed HCHO treated G.N. Cake:

Another growth trial was conducted on 12 buffalo calves divided into 2 groups fed either untreated GN cake or HCHO treated GN Cake (60% BPP in concentrate) for a period of 4 months. In this particular experiment as well, the growth rate recorded was 30-35% in the HCHO treated mustard cake group, over the control group. The higher feed conversion efficiency also seen in this experiment makes it an attractive and cheaper technology.

Additional benefits of HCHO treatment on both types of cakes:

HCHO Treatment of GN Cake:  After finishing the growth trial on kids, the Aflatoxin level was measured in leftover untreated and as well as treated cake samples. Interestingly, it was found that the aflatoxin level was 3 times more in the untreated cake. This suggests that apart from protecting cake protein, HCHO treatment does not allow the fungus to grow on the cake. Thus, the HCHO treatment of GN Cake arrests the further growth of fungi, and no further increase in Aflatoxin level in the cake happens, while in the untreated cake the fungus grew unchecked and this increased its aflatoxin content.

HCHO treatment of Mustard Cake:

After the growth trial on kids, these animals were slaughtered and the organs were subjected to histopathological examination.  Results showed that there was a massive cellular degeneration of most of the organs in animals fed untreated cake, while in the treated group all the organs were intact.  This proved that HCHO treatment prevents the conversion of glucosinolate, present in the mustard cake to thiocyanate in the rumen. Thus, feeding of Mustard Cake treated with HCHO has no toxic effect on ruminants, suggesting that its feeding is safer in two ways: does not cause any organ damage to the animal and it also prevents Thiocynate Poisoning in ruminants.

Effect of feeding Bypass Protein on Reproductive aspects of dairy animals

Some experiments on the feeding of bypass protein were conducted by the LPM Division of NDRI Karnal, on the reproductive aspects of the animals. It demonstrated that Bypass Protein feeding has some positive effect on reproduction. Because of higher growth rate and feed conversion efficiency, it leads to early maturity, resulting in a slight decrease in age at first calving, an improved conception rate, and a decreased inter-calving period in females. In addition to that, the lower ammonia level in circulation has a positive effect on foetal growth, because the higher ammonia levels in circulation can also cause damage to the foetus. Furthermore, in young bulls, due to more supply of Amino Acids on feeding bypass protein, it could also lead to a better libido as well as better semen quality.

Feeding Bypass Protein to lactating animals

Effect on milk yield of buffaloes on feeding bypass protein: 

12 lactating buffaloes were divided into 2 groups and fed either untreated GN cake or HCHO treated G.N. Cake (@1g HCHO/100g cake protein). The bypass protein level in the concentrate was 60% of total protein.  After 4 months of the feeding trial, the average milk yield in the treated group was 12-14% higher.  The FCM yield was still better in the treated group because there was a slight increase in the fat percentage of milk from treated cows. The increase in fat percent after feeding Bypass Protein has been very consistently seen in a number of other experiments. Perhaps the increased Methionine supply on feeding Bypass Protein provides Methyl donor for Fat synthesis, resulting in more fat in milk.
Effect on milk yield of goats on feeding bypass protein:  A trial on 14 lactating goats divided into two groups was conducted. While the control group was fed concentrate which contained untreated mustard cake, the experimental group was fed concentrate having HCHO treated mustard cake, forming 60% bypass protein in the concentrate. The trend regarding the increase in milk yield was just similar in the HCHO treated group as in other experiments, along with higher fat content, as observed in the case of lactating buffaloes.
Milk samples from goats fed HCHO treated mustard cake showed no trace of either Formalin or Thiocyanate, Thus, such milk is absolutely safe for human consumption, apart from the fact that HCHO treatment of this cake is also safe for animals, as demonstrated earlier in goat kids, through histopathological studies.

Effect on milk yield of crossbred cows on feeding bypass protein:

A) Under NDRI- American Soybean Association Collaborative Project: A trial was conducted on 12 Lactating Cross Bred cows divided into two groups, fed either Roasted Soybean cake (140 deg C for 30 Min), or Soyabean cake as such, for 3 months, to make bypass protein as 60% in concentrate. At the end of the trial, the treated group showed 12-14% higher milk yield than the untreated group. Though the results were quite encouraging, it has been already mentioned that this is not a cost effective technology. As compared to roasting, the HCHO treatment of cake is a much cheaper technology to convert highly degradable oil cakes into Bypass Protein.

B) Under NDRI-NDDB collaborative project: A trial was conducted at NDRI on 12 lactating crossbred cows divided into two groups. The experimental group was fed Bypass Protein feed having HCHO treated G N Cake, while the control group was fed feed containing untreated G.N. cake. After the 3 months of trial, the increase in milk yield was recorded to be around 13 to 14% in the group fed bypass protein over the control group, along with better feed conversion efficiency and cost-effectiveness.
Simultaneously a similar trial was conducted by NDDB, using the same bypass protein feed, in the rural areas around Anand.  However, the increase in milk yield in the rural area was still higher than recorded at NDRI. The yield varied from 15-20%. After getting convinced, then NDDB Chairman Dr. Amrita Patel decided to go for large scale production of Bypass protein.

The biochemical explanation for the increase in milk yield:

A) Quantum of Lactose synthesis decides the quantum of milk to be synthesized in Mammary Gland
B) Lactose regulates the osmotic pressure of milk. More the lactose synthesis, more amount of water
Mammary Gland has to suck from blood, which increases milk volume.
C) Lactose synthesis in Mammary Gland depends upon the supply of glucose, part of which is also converted to galactose, for lactose synthesis.
D) More supply of glucose to Mammary Gland, means more Lactose synthesis.
E) Bypass Protein feeding provides extra supply of AA to liver for more Gluconeogenesis, as propionate supply is not sufficient, due to less ingestion of soluble carbohydrates.
F) Since, the other two milk constituents viz. Protein and Fat have to keep pace, to match the lactose level in milk. This results in more Milk Volume or in other words more Milk yield.
The first commercial plant for manufacture of Bypass Protein was commissioned at Baroda, under Indo-Australian Collaborative Project in 2004.

DR. SK MUKHERJEE, DAIRY CONSULTANT, GUAHATI

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