I.                          Concentrate Feed Stuffs

A concentrate is usually described as a feed or feed mixture which supplies primary nutrients (protein, carbohydrate and fat) at higher level but contains less than 18% crude fibre (CF) with low moisture. In general, concentrates are feeds that are high in nitrogen free extract (NFE) and Total Digestible Nutrients (TDN) and low in crude fibre.

On the basis of the crude protein content of air dry concentrates, these are classified as either energy rich concentrates when crude protein (CP) is less than 18% or protein rich concentrates when the CP value exceeds 18%.

1            Energy sources

These are described under the following categories:

1. Grains and seeds
   1. Milling by-products
   1. Molasses
   1. Roots and tubers

1.1.  Grains and seeds

Grains are seeds from cereal plants, members of the grass family called Graminaea. Cereal grains are essentially carbohydrates, the main component of the dry matter being starch, which is concentrated on the endosperm. All cereal crops are annuals (Kharif). By- products of harvested grains as chaff, stover and straw are utilized as low quality forages for ruminant animals. Moreover, many of the grains are milled or processed in some manner thereby creating additional by-products which can be fed to livestock with varying degrees of nutritive values. In India except for poultry, swine and lactating dairy animals, grains are not usually fed for livestock production, because of high cost due to high demand by human beings.

The crude protein content of grains and seeds varies between 8-12%, which again is deficient in lysine and methionine. The oil which is mostly present in the embryo is highest in oats (4-6%) and lowest in wheat (1-2%). Cereal oils are unsaturated, the main fatty acids being linoleic and oleic and because of this, the cereals tend to become rancid quickly and also produces soft body fat in non-ruminants. The crude fibre content of harvested grain is highest in oats and rice, which contain a husk or hull formed from the inner and outer paleae and is lowest in the naked grains like wheat and maize. All cereals are deficient in vitamin D and calcium, but are moderately rich in phosphorus and vitamin E.

Cereal grains and cereal by-products

Nutrient composition of grains

The name cereal is given to those members of the Gramineae which are cultivated for their seeds. The dry matter content of grain depends on the method of harvesting and storage conditions but is generally within the range of 80-90%. Protein constitutes 85-90% of the nitrogenous compounds. The protein occurs in all tissues of cereal grains, but higher concentrations are found in the embryo and aleurone layer than in the starchy endosperm pericarp and testa. The protein content of grain though variable, normally ranges from 8-12%. The lipid content of cereal grains also vary with species, normally ranges from 1-6%. Maize and oat contain 4-6% oil, while sorghum 3-4% and wheat, barley and rice

contain 1-3% oil. The embryo or germ contains more oil than the endosperm. Cereal oils are unsaturated, the main acids being linoleic and oleic and because of this, they tend to become rancid quickly.

The crude fibre content of the harvested grains is highest in those such as oats or rice which contain husk and is lowest in grains without husk like wheat and maize. The husk has a diluent effect on the grain as a whole and reduces the energy value of proportionally. Starch occurs in the endosperm of the grain in the form of granules, whose size and shape vary with different species. Cereal starch consists of about 25% amylase and 75% amylopectin, although waxy starches contain greater proportions of amylopectin. The cereals are deficient in calcium and vitamin D. Though phosphorus content is higher, but part of this is present as phytic acid. Cereal phytates have the property of being able to bind dietary calcium and probably magnesium, thus preventing their absorption from the gut. Except yellow maize, all other cereals are low in provitamin A. They are good sources of vitamin E and thiamin, but have a low content of riboflavin. Cereals generally form a lower proportion of the total diet of ruminants.

Following are some of the important inherent problems in the use of grains for ruminant feeding:

1. In ruminant animals, high concentrate ration may cause digestive disturbances, such as acidosis. Ruminants need some roughage, to stimulate the rumen papillae.
2. Some grains must be processed before they can be fed. The need for processing is primarily governed by the type of grain and the particular animal being fed.
3. Grains are deficient in calcium and certain vitamins. Most grains contain less than 0.1% calcium. Adequate amounts of phosphorus are generally present in grain, but the calcium to phosphorus ratio is highly imbalanced. Additionally, grains are also deficient in certain vitamins like vitamin A and vitamin D. However, yellow maize is rich in b carotene, which is a precursor of vitamin A.

Structure of grain

Grain develops from the ovary and its ovule after fertilization by pollen. The flower structures of various cereal plants are different, hence these differences reflect in the structure of the individual grain in kernel. In maize, the male and female structures are found in separate flower structures on the plant. The male flower structure commonly referred to as the tassel, is located at the top of the corn stalk. Pollen is shed from tassels and subsequently comes into contact with the female flower structure thereby

producing the grain. The female structure contains a central rachis commonly referred to as cob. The cob contains a series of rows of sessile spikelet and is enclosed by overlapping bracts (husks). The silks which are found on the corncob structure are the stigmas, the pollen receiving organs. Each spikelet contains two flowers one fertile and another sterile.

The grain of barley, oats, wheat, rice and sorghum develops from flowers which contain the ovary, three stamens and two scale like lodicules. These structures are surrounded by a pair of bracts called the lemma and the palea. In rye and wheat, the lemma and palea are loosely attached to the grain.

During threshing these particles are separated from

grain and constituted what is known as chaff.                     Fig. 1.1 Structure of grain

Barley, rice and oats retain their lemma and palea during threshing, thus giving rise to structures called husks or hulls. In barley, the lemma and palea fuse with the grain. In oats, the lemma and palea do not fuse with the kernel but enclose and adhere tightly to the entire grain. This hull structure can be removed during processing, resulting in dehulled oats called groats. Rice hulls are removed during processing.

Individual kernels of grain are called caryopses. Grains which contain husks (oats, barley and rice) are called covered caryopses; whereas, grain lacking husks (maize, wheat, rye and sorghum) are referred as naked caryopses. Each kernel exclusive of the husk is composed of two main parts – pericarp and seed.

Pericarp

The pericarp consists of two layers. The outer layer contains the epidermis and hydroderm collectively referred to as the beeswing. The inner layer of the pericarp contains cross cells and tube cells. Throughout the ripening process of grain, the inner most layer of pericarp becomes distorted and torn and thus giving a tube like appearance called tube cells.

Seed

The seed portion of grain can be divided into four parts: 1) seed coat 2) hyaline layer (nucellar layer), 3) endosperm and 4) germ (embryo). When grain is processed in such a way that the germ and starch endosperm are removed the composite of the remaining parts of the seed and the pericarp is called the bran. The seed coat is either one or two layers thick. There is very little cellular structure in the region. Likewise, the hyalinase layer lacks any cellular structure, but rather acts as an embryo sac.

Endosperm

The endosperm of grain can be divided into two parts called the aleurone and the starchy endosperm.

Aleurone

The aleurone surrounds the starchy endosperm of grain, but does not encampass the scutellam of the embryo. The cells of aleurone are thick walled, cuboidal, and rich in oil, niacin and mineral matter. Phytic acid is also produced in larger quantities in this region. The number of layers of cells in this region varies according to type of grain. Wheat, rye, oats and sorghum have generally one layer of cells in the aleurone. Depending on the particular variety, maize may contain from 1 to 6, barley 2 to 4 and rice 2 to 6 layers.

Starchy endosperm

The starchy endosperm portion of grains contains thin walled cells that are highly variable in shape, size and contents. Pentosans are found in large amounts in the cell walls of this region, but starch and protein take up most of the cell contents. Starch is found primarily in the form of granules, with protein filling the intergranular spaces. In wheat, the cells adjacent to the aleurone are relatively higher in protein and lower in starch than the rest of the starchy endosperm. The concentration of starch in maize depends on type of the maize and the area of the kernel being analysed. The endosperm of the maize is divided in to two regions – the crown and the horny region. The crown contains loosely packed starch granules with little protein. The protein content of horny region is much higher than crown region.

Germ (Embryo)

Upon germination, food reserves in the endosperm are mobilized and passed on top of the embryo by scutellum. The plumule of the embryo gives rise to the growing bud and the radical to root system.

1. Maize (Zea mays)

Synonym: Corn

Local names: Hindi: Makka, Makai, Bhutta Manipuri: Chujak Marathi: Bhutta Tamil: Makka cholam Malayalam: Makka cholam Telugu: Mokka javanalu Kannada: Makkejola Konkani: Mako Urdu: Makka

Maize is the world’s most important feed grain because of its high nutritive value and good agronomic features. Maize can produce more energy per acre than any other cereal grain due to its C4 photosynthetic pathway. The C4 plants have a tropical origin and are inherently more productive than plants with C3 pathway. Maize is also unique among grains in having the male and female flower organs separately on same plant, which allowed development of high yielding maize varieties. There are seven types of maize including dent, flint, flour,

pop, sweet, waxy and pod maize. Dent corn is the primary type grown as feed and sweet corn is the major type grown for human consumption. Dent

Fig. 1.2 Maize grain

corn is characterized by a dent or indentation at the top of the kernel, formed when the starch shrinks during drying.

Nutritive value

Maize is a high energy grain because it is high in starch and oil and low in fibre. Maize contains about 70% starch, 85-90% TDN, 4% oil and about 8-12% protein. The grains should be ground before feeding to the ruminants, otherwise they will escape digestion. Maize contains starch, which composed of about 25% amylase and 75% amylopectin. The starch in maize is more slowly digested in the rumen than that of the other grains and at high levels of feeding a proportion of starch passes in to the small intestine, where it is digested and absorbed as glucose. This may have advantages in conditions such as ketosis. The maize kernel contains two types of proteins. Zein occurring in the endosperm is quantitatively the more important, but this protein is deficient in the indispensible amino acids lysine and tryptophan. Now new variety of corn (opaque-2) has been evolved which is rich in lysine and protein. A newer variety, Floury-2, has increased contents of both methionine and lysine. A number of different types of maize exist and the grain appears in variety of colours, yellow, white or red. Only yellow variety has a fair amount of cryptoxanthin, a precursor of vitamin

A. Yellow maize also contains xanthophylls which are important in poultry production for providing the yellow coloration of the egg yolk and of the skin of the broilers. Maize is a fair source of vitamin E and low in vitamin D and the B complex vitamins. In common with all plants, maize is devoid of vitamin B₁₂ activity.

Deleterious factor

Maize does not intrinsically contain any toxic and deleterious compounds. However, it is often contaminated with mycotoxins which are of concern in animal feeding. The major mycotoxin of concern is aflatoxin produced by the mold Aspergillus flavus. The mold infects

maize both in the field and storage. Drought and insect damage promote infection of the developing grain.

1. Sorghum (Sorghum bicolor)

Local names: Hindi: Jowar Marathi: Jowari Tamil: Cholam Sorghum resembles in feeding value to that of

maize. It is more drought resistant than maize. The

kernel of sorghum is very similar to that of maize, although smaller in size. Like maize, sorghum is also a C4 plant accounting for its high productivity and tolerance to high temperatures.

Nutritive value

Sorghum grain is very similar to maize in composition. It generally contains more protein but less oil than maize and has no pigmenting xanthophylls. Sorghum contains about 65% starch, 80-85% TDN, 2-3% oil and about 8-12% protein.

Grains are slightly less palatable than maize because of the presence of tannins. The grains should be

Fig. 1.3 Sorghum grain

ground before feeding the ruminants, otherwise they will escape digestion. Care is needed in the grinding process as this may produce a fine powder, which is pasty and unpalatable. Tannins in sorghum greatly reduce protein availability both in rumen and small intestine. Lysine, threonine and methionine are the limiting amino acids in sorghum. Grains typically have very low calcium, high phytate phosphorus, no vitamin B₁₂ and very little vitamin A activity.

Deleterious factor

The principal deleterious factors in sorghum grain are polyphenolic compounds, known as condensed tannins. Most of the biological effects of tannin are associated with their ability to react with protein. In the digestive tract tannins may react with digestive enzymes reducing nutrient digestibility. They also react with dietary proteins forming indigestible complexes. Various processing methods can be used to overcome the effects of sorghum tannin. Treatment with alkali, such as sodium or ammonium hydroxide or anhydrous ammonia is effective. Polyethelyne glycol which forms complexes with tannins has also been shown to be an effective additive to improve the feeding value of high tannin sorghum.

1. Wheat (Triticum aestivum)

Local names: Hindi: Gehun Kannada: Godhi Manipuri: Gehun Marathi: Gehun Sanskrit: Arupa, Bahudugdha, Godhuma Tamil: Godumai, Godumbaiyarisi Telugu: Godumalu Urdu: Gehun

Wheat is the world`s most important crop. It is grown primarily for human consumption. Wheat belongs to the genus Triticum.

Nutritive value

Though wheat is a good source of energy containing 75-80% TDN, it is rarely used for livestock feeding in India due its higher cost and higher demand for

human consumption. Only damaged wheat is used

Fig. 1.4 Wheat grain

for feeding animals. Grain of wheat is highly variable in composition. Depending upon the variety, crude protein content ranges from 8-14%. Wheat is superior to maize in protein content and quality. Lysine, threonine and methionine are the major limiting amino acids in wheat grain. Climate, soil fertility and variety influence the protein content. The most important protein present in the endosperm is a prolamin and a glutelin. The mixture of protein present in the endosperm is often referred as gluten. The amino acid composition of these two proteins differs, glutenin containing about three times as much lysine as that present in gliadin. All glutens possess the property of elasticity. Glutens form dough which traps the gases produced during fermentation. Finely ground wheat forms a pasty mass in the mouth and rumen and this may lead to digestive upsets. Newly harvested wheat is apparently more harmful in this respect than wheat which has been stored for some time. When wheat grain is fed in large amounts, because of the rapid fermentation of the grain in rumen, animal is more prone to lactic acidosis.

Deleterious factor

There are no significant toxins in wheat. It is not normally infected with mycotoxin producing fungi, so mycotoxins are not of concern unless the grain is improperly stored. Occasionally it may be infected with ergot.

1. Barley (Hordeum vulgare)

Local names: Hindi: Jav, Jau Kannada: Jave- godhi Malayalam: Barli, Yavam Marathi: Satu, Jav Sanskrit: Aksata, Akshata, Dhanyaraja Tamil: Barliarisi Telugu: Barlibiyam, Dhanuabhedam Urdu: Jao, Jav

Barley is widely grown in Europe and in the cool and dry climates of North America and Asia. It is also one of the very popular grains in feeding livestock.

Nutritive value

Maize, wheat, triticale and sorghum are recognized

as high energy grains, whereas, barley and oats are lower in energy content. The lower energy

Fig. 1.5 Barley grain

value of barley is due to its lower starch content, a higher content of poorly digested glucans, and higher fiber content. Barley contains water soluble carbohydrates called

b-glucans which are poorly digested, especially in non-ruminants. However, the glucans are digested by microbial action in rumen. The crude protein varies from 11-16% and TDN from 78-80%. The lipid content of barley grain is low; usually less than 2.5% of dry matter. Barley is deficient in the amino acid lysine.

In many parts of developed countries barley is used for fattening beef animals. Beef cattle are fattened on concentrate diet consisting of about 85% bruised barley without the use of the roughage. In this process the barley is usually treated so that the husk is kept as one piece and at the same time the endosperm is exposed, the best results being obtained by rolling the grain at a moisture content of 16-18%. Storage of high moisture barley of this type can present a problem because of the possibility of mold growth. Satisfactory preservation of the moist grain can be obtained if it is stored anaerobically. An additional or alternative safeguard is to treat the grain with a mould inhibitor such as propionic acid. Certain hazards such as rumen acidosis and bloat can be encountered with high concentrate diets given to ruminants and it is necessary to introduce this type of feeding gradually over a period of time. There are no significant toxins in barley.

1. Oat (Avena sativa)

Oat is a minor grain and is likely to become less important as a feedstuff for animals. Oat is of low importance simply because the yield per hectare is much lower than other grains. For a farmer it would be economical to produce oat, if the price per ton is higher than that of other grains to compensate for the lower yield; otherwise there is no economic incentive to grow oat. The use of oat as animal feedstuff may decline in future, but it may become more important in human nutrition due to the presence of soluble fibre which has favourable effects to reduce serum cholesterol.

Nutritive value

It is a feed of choice for feeding horses. It can be fed to the ruminants also, but is less suitable for

Fig. 1.6 Oat grain

poultry and pigs because of the high fibre content. Oats are a low energy grain because of their low starch and high fibre content. The nutritive value of oats depends to large extent on the proportion of kernel to hull. The proportion of hull in the whole grain depends upon the variety, environment and season and can vary from 23-35%. Oats of high hull content are richer in crude fibre and have a lower metabolisable energy value than low hulled oats. The soft physical nature of the hull and high oil content contribute to the high palatability of oats. The crude protein content ranges from 8-12% and TDN 70-73%. Oats have the highest quality protein of any cereal grain and often have higher protein content and the amino acid distribution is the most favourable of any of the cereal grain. Still oat proteins are deficient in the essential amino acids like methionine, histidine and tryptophan. The lysine content is also low, but is slightly higher than that of the other cereal grains. The oil content of oats is higher than (5% oil) that of most of the cereal grains and about 60% of it is present in endosperm. The oil is rich in unsaturated fatty acids and has a softening effect on the body fat. Oat grain has a higher mineral content than other grains. It should be given crushed to the ruminants and ground to the poultry and pigs.

1. Rice (Oryza sativa)

Local names: Hindi: Chaval Tamil: Arisi Telugu: Biyyam Rice is a major foodgrain for millions of people in

the tropics especially Asia. It is good source of

energy but is seldom used for livestock feeding in Asia. About more than 40,000 types of rice varieties are grown in the world. Its by-products like rice polish and rice bran are extensively used for livestock feeding in India.

Nutritive value

Unprocessed rough rice contains about 8-10% crude protein, 9% crude fibre, 1.9% ether extract and 6.5% ash. The TDN content varies from 78-

82%. The unprocessed rice contains about 25% of its weight as hulls. Rice should be ground or

Fig. 1.7 Rice grain

cracked before feeding to animals. Rice hulls are high in silica and are abrasive to both feed mill equipment and digestive tract. The hulls are almost totally indigestible and are not recommended for livestock feeding.

1.1.7          Rye (Secale cereale)

Rye is the grain most tolerant of adverse growing conditions, like extreme cold and acidic soil conditions. Because of its poor palatability and presence of numerous deleterious factors use of rye in animal feed is very limited.

Nutritive value

Rye grain is very similar to wheat in composition although rye protein has higher lysine and lower tryptophan contents than wheat protein. Protein content of rye varies from 10-14% and TDN 75- 80%. It is regarded as the least palatable of the cereal grains. It is also liable to cause digestive upsets and should always be given with care and restricted amounts.

Deleterious factors

Rye has never given favourable results in animal feeding as its nutrient composition suggests that it should. Numerous deleterious factors have been

suggested as being responsible for this, including alkyl resorcinols, ergot, pectins, pentosans and

Fig. 1.8 Rye grain

water soluble glucan like gums. Rye contaminated with ergot (Claviceps purpurea) may be dangerous to animals. This fungus contain a mixture of alkaloids, of which ergotamine and ergometrine are the most important and in view of their action on uterine muscle, have been implicated as a cause of abortion in cattle consuming ergot infested rye. More importantly chronic poisoning by the alkaloids causes injury to the epithelium of the capillaries reducing blood flow and resulting in coldness and insensitivity of the extremities. Subsequently lameness and necrotic lesions occur in the in the feed, tail and ears of mammals. Like wheat, rye should be crushed or coarsely ground for feeding to animals. Studies with cattle suggest that to avoid depressing performance rye should be restricted to 40% or less of diet.

1. Triticale (Triticum secale)

Triticale is a hybrid cereal derived from crossing wheat with rye. The objective in crossing the two cereals was to combine the desirable characteristics of wheat such as grain quality, productivity and disease resistance with the vigour and hardiness of rye.

Nutritive value

The crude protein content ranges from 8-12% and TDN 75-85%. Protein content is similar to wheat and the quality of protein in hybrid varieties are better than wheat because of high proportion of lysine and sulphur containing amino acids. However, it is

deficient in amino acid-tryptophan.

Deleterious factors

Fig. 1.9 Triticale grain

As with rye, triticale is subject to ergot infestation. Studies using this hybrid have demonstrated increased liver abscesses in steers when compared with sorghum diets. Triticale contains trypsin inhibitors and alkyl resorcinols and both of these have been implicated in problems

of poor palatability and performance in livestock. Due to its poor performance, it is generally recommended that triticale be limited to 50% of the grain in the diets of farm animals.

1.1.9           Millet

The name millet is frequently applied to several species of cereals which produce small grains and are widely cultivated in tropics. The most important members of this group include Pennisetum typhoides (Indian pearl millet or Bajra), Pennisetum americanum (pearl millet), Panicum miliaceum (broomcorn millet), Setaria italic (Italian millet), Eleusine coracana (finger millet), Pspalum scorbiculatum (ditch millet) and Echinochloa crusgalli (Japanese millet). Millet has traditionally been viewed as a poor persons’ crop, lacking prestige and appeal but it holds great potential as a food crop adapted to marginal, drought stricken areas. Millet grain is typically is produced in spike like panicle with small round seeds less than half the diameter of sorghum seeds.

Nutritive value

Fig. 1.10 Millet grain

The composition of millet is very variable, the crude protein content being generally within the range 10-12%, the ether extract 2-5% and crude fibre 2-9%. Millet has a nutritive value very similar to that of oats and contains a high proportion of indigestible fibre owing to the presence of hulls which are not removed by ordinary harvesting methods. TDN content varies from 75-85%. Millet is a small seed and is usually ground for feeding to cattle.

1. Pearl millet (Pennisetum typhoides)

Local names: Gujarati, Hindi, Urdu and Punjabi: Bajra, Rajasthani and Marathi: Bajri,

Telugu: Sajjalu, Kannada: Sajje, Tamil: Kambu

Pearl millet is the most widely grown type of millet. Grown in Africa and the Indian subcontinent since prehistoric times, it is generally accepted that pearl millet originated in Africa and was subsequently introduced into India. Pearl millet is well adapted to production systems characterized by drought, low soil fertility, and high temperature. It performs well in soils with high salinity or low pH. Because of its tolerance to difficult growing conditions, it can be grown in areas where other cereal crops, such as maize or wheat, would not survive. Today pearl millet is grown on over 260,000 km² worldwide. It

accounts for approximately 50% of the total world production of millets. India is the largest producer

Fig. 1.11 Pearl millet grain

of pearl millet. It is locally known as bajra, and is primarily consumed in the states of Haryana, Rajasthan, Gujarat and Madhya Pradesh.

Nutritive value

It resembles in feeding value to that of sorghum. The crude protein ranges from 12-15% and TDN from 70-75%. It is also rich in tannins. It can be used in place of maize in livestock feeding.