The composition of body of buffaloes gives an idea about nutritional requirements. Body of buffaloes consist of fat, 5-18%; water, 50-74%; protein, 16-19%; minerals, 3-5%; carbohydrates, <1%; vitamins, very low level. In the body protein and minerals are generally constant under normal condition but fat and water content vary according to plane of nutrition, age and health condition. In order to maintain normal health, production and reproduction buffaloes need dietary supply of all these nutrients or their precursors except some vitamins which are synthesized in body. Chemically feeds of buffalo are composed of water, proteins, fats, carbohydrates, minerals and vitamins.

Water

Water is needed as solvent for most of the dietary nutrients, for digestion and transport, as structural constituent and maintenance of body homeostasis. Water requirement vary with nature of diet, milk production, weather and many other factors. The major requirement of water is met through ingestion. Since storage of water in body is limited, buffaloes should be offered to drink water at least 3 times daily. Water in feeds is variable in quantity, ranging from 90 percent in succulent fodders like berseem to 8-10% in straw, dry fodders and concentrate ingredients. Water content in feed is expressed as dry matter (DM) and is estimated by percent loss in weight on overnight drying at around 100°C.

Protein

Protein is one of the major constituents of body tissue of buffalo. Proteins are synthesized in body from amino acids obtained by digestion of dietary or rumen microbial proteins. Adequate supply of protein is important for maintenance of body, growth, milk production and reproduction. Storage of protein in body is very limited and hence, its daily supply is essential. In ruminant buffaloes rumen microbes supply good quality of protein rich in essential amino acids.  The non protein nitrogen (NPN) compounds present in feeds are amino acids, urea, and ammonium salt. NPN make about as high as one third of the total nitrogen in grasses. The rumen microbes can utilize NPN compounds for synthesis of proteins and amino acids. These microbes are subsequently digested by intestinal enzymes of buffalo releasing microbial amino acid. Thus buffaloes can meet most of the protein requirements from microbes in rumen.

The method most widely used for expressing the protein requirement for buffaloes and the extent to which a feed could meet these requirements is one based on the measurements of digestible crude protein (DCP) or crude protein (CP). Crude protein is estimated by measuring nitrogen (N) content of feed. CP = N x 6.25.  CP includes both true protein and NPN. The ideal system for calculating the N requirements of buffaloes must provide estimates of the total and individual amino acids absorbed from the small intestine. These amino acids are supplied partly by microbial protein synthesized in the rumen and partly by dietary protein, which has escaped fermentation in the rumen. The value of dietary NPN (non protein nitrogen) sources and the portion, which is degraded in rumen, depends entirely upon the extent they are utilized for microbial protein synthesis and good quality protein is protected from microbial degradation. However priority should be given to meet the N requirement of rumen microbes and to optimize rumen microbial growth, which is essential for overall digestion of fibrous feeds in rumen. Hence new system of protein quality evaluation based on rumen degradable protein (RDP) and rumen escape protein (UDP or RUP) are being proposed which take care of the amount of microbial as well as the amount of bypass protein requirement of ruminants. The proteins in practical diet supply some dietary protein that escapes rumen fermentation, and this protein plus the microbial protein produced from supplemental NPN may be enough to produce 12 Kg 7% FCM /d. Similarly, the microbial protein synthesis for growing buffaloes with a functional rumen plus the natural bypass protein in practical diets where due consideration is given to meet energy and CP or DCP requirement may be enough to meet amino acid requirement for 700 g growth rate per day. As milk production and growth rate increases, a substantial amount of additional dietary protein from protein supplements must escape rumen fermentation to meet the animal’s requirements. In India most of the values of feed composition and animal’s requirement has so far been expressed in terms of DCP or CP and sufficient data on requirement of degradable and un-degradable protein are not available. Keeping in view these facts and considering production level of most of the Indian buffaloes DCP or CP system has been retained as the unit for expressing nutritive value of feeding and protein requirement in the present book.

Lipids

Lipids are triglycerides of fatty acids. Lipid content of feed is estimated by extraction of fats using petroleum ether and the fat thus estimated is called EE (Ether extracts) and expressed as % of dry matter. Lipids contribute to energy requirement, milk fat synthesis and also required for maintaining tissue integrity. Extra fat remains stored in adipose tissue and are mobilized during demand supply mismatch of energy in body. Lipids produce 2.25 times more energy than carbohydrates. They also act as insulator and carrier of fat soluble vitamins. A fatty acid called linoleic acid is an dietary essential component. Its deficiency causes scaly skin and reproductive failure.

Carbohydrates

The group of nutrients called carbohydrates includes the sugars, starch, cellulose, gums and related substances. Among carbohydrates glucose and glycogen are present in animal body and are major source of energy. Carbohydrates (both simple sugars and complex fibrous cell wall materials) make up 75% of plant dry matter, upon which animal life primarily depends.  Carbohydrates in plants are partitioned into two groups, soluble carbohydrates (called NFE or nitrogen free extractives) and insoluble cell wall components comprising cellulose, hemicellulose linked to lignin are called crude fibre (CF). NFE is easily digested by digestive enzymes of buffalo but crude fibre is not. Crude fibre is digested by rumen or gut microbes only. Digestion of all carbohydrates produces volatile fatty acids in rumen which is absorbed into body of buffalo and produce energy on metabolism. Simple carbohydrates which escape microbial fermentation give rise to glucose or simple carbohydrates and is absorbed from intestine. Lignin present in plant is the main hinderence to microbial fermentation of plant carbohydrates. More mature the plant is lignin content is high. Hence fodders should be harvested in preflowering immature stages so that it is easily digested by rumen microbes. Feeds containing more than 18% crude fibre are called roughages (green fodders, grasses, tree leaves, straws, etc.) and feed containing less crude fibre but more NFE are termed as concentrates (grains, brans and oilcakes). Fibre content of feed also expressed as neutral detergent insoluble fibre (NDF) and acid detergent insoluble fibre (ADF).

Minerals

Minerals constitute about 2 to 4 % of the animal tissue and play a vital role in nutrition of buffaloes. Among minerals Calcium, phosphorus, sodium, potassium, magnesium, sulpher and chloride are required in relatively larger quantity (called macro elements or macrominerals) whereas copper, zinc, cobalt, manganese, iodine, iron are required in trace quantity (called trace elements or trace minerals). Minerals play important role in bone formation, body ionic balance and in important enzyme systems, growth, milk production and reproduction of buffaloes and hence need to be present in sufficient quantity in diet. Excess mineral in diet or any imbalance of minerals are also harmful.

Vitamins

Vitamins are required for normal body metabolism, growth, milk production and reproduction. Some of the vitamins are synthesized in body or by rumen microbes of buffaloes (Vitamin C, K, D and B complex) whereas some are dietary essential (Vitamin A and E).