Different requirements of dairy animals are as follows
Water
Water is the cheapest nutrient. Animal get water from three sources:
Metabolic water is an insignificant source compared with the water ingested freely or in feed. The sum of Free water Intake and the water ingested in feed is the total water intake (TWI). Large amount of fresh and clean drinking water should be available to the dairy animals all the times. Three to four units of water is normally required by dairy animal for each unit of dry feed consumed. Requirement of water is governed by different factors like what is the physiological state of the animal, what type of feed consumed, and what are climatic conditions. Water requirement of a dairy animal when not in milk is 26 to 37 liters per day, and this requirement increases at arate of four litres for each litre of milk produced. Requirement of water can also be determined by this equation:
Water intake (gal/day) = 4.22 + (0.19 x DM intake) + (0.108 x pounds of milk) + (0.374 x ounces of sodium)
+ (0.06 x minimum daily temperature in F)
Dairy animals are very sensitive to the quality of water as availability of inadequate or poor quality water can limit milk production and growth and may cause even health problems.
Dry Matter Intake
Dry matter intake is quantity of dry matter which is consumed by an animal over a period for 24 hours. It is usually measured in %age. DMI is normally calculated as 3-4 % of body weight. An average size cattle DMI is 2.5 - 3% of body weight. A dairy animal may reach maximum daily DMI (4% of Body weight) not later than 10 weeks after calving.
Energy
The capacity to do work is called energy. It is the basic requirement of animal and essential to maintain normal body functioning. Energy is quantitatively the major nutrient required by dairy cattle after water.
Carbohydrates, fats and protein are the main sources of energy. Mostly the energy is supplied to the dairy cattle from carbohydrates being the most economical. Protein is also a good source of energy but it is usually 5 to 10 times higher in price as compared to carbohydrates and therefore its use is less as energy source. Fat is very good source of energy and supply 2.25 more energy as compared to carbohydrates and protein. It is mainly included in the rations of young calves but may also be added to the rations of lactating dairy animals.
On the basis of energy losses in body energy can be divided as follows:
Gross energy refers to the total energy in feed, which is determined by complete oxidation (burning) of the feedstuff and measurement of the heat produced. The energy value is expressed in calories. Common feedstuffs are similar in gross energy content, but differ in feeding value because of differences in digestibility.
Digestible energy is gross energy minus fecal (manure) loss. These losses will be greater for high fiber rations than for low fiber rations.
Other losses include those in urine and gas. In the rumen, considerable methane is produced, representing an energy loss because the animal cannot use methane and must eructate (belch) the gas. These losses, added to fecal losses, are considered in calculating the metabolizable energy.
Heat is produced during digestion and metabolism. Other than during cold weather, this heat has no value and represents a loss of energy. The remaining energy is net energy (NE). NE system divides energy into NE for maintenance (NEm), NE for growth (NEg) and NE for lactation (NEl). NEl is energy required for maintenance plus milk production during lactation.
Total digestible nutrients (TDN) is another method of expressing the energy content of feeds or the energy requirements of cattle. TDN is comparable to digestible energy. It has been in use longer than the net energy system and more values are available for feedstuffs.
TDN = Digestible NFE + Digestible crude fiber + Digestible protein + (Digestible ether extract x 2.25)
Carbohydrates
Carbohydrates are the major source of energy in diets for dairy cattle and usually comprise 60-70% of total diet. The main function of carbohydrates is to provide energy for rumen microbes and the host animal. A secondary, but essential, function of certain types of carbohydrates is to maintain the health of the gastrointestinal tract. There are two major categories of carbohydrate as structural carbohydrates and non structural carbohydrates. Non structural carbohydrates are found inside the cell of plants while structural carbohydrates are found inside the cell wall. Non structural carbohydrates are more soluble than structural carbohydrates.
Non structural carbohydrates include sugars, starches, organic acids, and other reserve carbohydrates such as fructans and are major sources of energy for high producing dairy cattle. Non structural carbohydrates are highly digestible.
Structural carbohydrates include cellulose hemicellulose, and lignin are classified as fiber, giving structure and strength to plant tissues. Simple-stomach animals, cat, dogs and poultry, cannot digest much fiber. Adult ruminants digest fiber because the microbial population in the rumen breaks it down into usable products. Lignin, which is also a component of plants, is not a true carbohydrate. This compound is virtually indigestible. Feed digestibility is lowered when lignin is present in large amounts, such as in mature forages.
Crude fiber, acid detergent fiber, and neutral detergent fiber are the most common measures of fiber used for routine feed analysis, but none of these fractions are chemically uniform. Neutral detergent fiber measures most of
the structural components in plant cells (i.e. cellulose, hemicellulose, and lignin). Acid detergent fiber does not include hemicellulose, and crude fiber does not quantitatively recover hemicellulose and lignin. Neutral detergent fiber is the method that best separates structural from nonstructural carbohydrates in plants, and NDF measures most of the chemical compounds generally considered to comprise fiber. Within a specific feed stuff, concentrations of NDF, ADF, and crude fiber are highly correlated, but for mixed diets that contain different fiber sources, the correlations among the different measures of fiber are lower. Neutral detergent fiber is the best expression of fiber available currently, but recommendations are also given for ADF because of its wide spread use.
Neutral detergent fiber (NDF) consists of ADF plus hemicellulose, and is often called cell walls. Because NDF represents the total fiber in a feed, it is highly correlated to intake, rumination, and total chewing time. Corrected for physical form, NDF provides the best measurement of effective fiber for formulating dairy rations.
The fineness at which forages are chopped during harvesting can alter the effectiveness of fiber for maintaining chewing activity. Hay crop silages should be chopped at a minimum of 3/8 inch theoretical length of cut (TLC) to provide 15 to 20 percent (weight basis) of the particles greater than two inches long. Chopping at 1/4 inch TLC provides only about 10 percent of the forage particles greater than two inches long. Corn silage should be chopped at 1/4 to 3/8 inch TLC. Rations based on 1/4 inch TLC silage should include 5 pounds of long stem hay to provide adequate "effective" fiber. Hay crop silage chopped at 3/16 inch TLC with less than 7 percent coarse particles should be fed with 8 to 10 pounds of long hay. Holstein cows need to chew about 11 to 12 hours per day or 12 to 14 minutes per pound of DM eaten to keep milk fat above 3.5 percent.
High fiber by-product feeds supply some "effective" NDF and can be used to partially replace NDF coming from forages in the ration. Whole cottonseed possesses the best forage NDF replacement value of commonly available by-product feeds fed in milking cow rations.
Starch, sugar, and pectin make up the highly digestible carbohydrate fraction in feeds termed non-fiber carbohydrates (NFC). Subtracting percent (DM basis) NDF, CP, ether extract or fat and ash from 100 provides an estimate of NFC percent in feeds.
(NFC% = 100 - [%NDF + %CP + %fat + %ash])
The term nonstructural carbohydrate is often used interchangeably with NFC but is analytically determined and may be slightly different from NFC.
Carbohydrate status of dairy rations has traditionally been evaluated with regard to measures of structural carbohydrates—ADF or NDF. However, optimum microbial growth in the rumen requires adequate amounts of NFC along with degradable intake protein (DIP) in the ration. Insufficient amounts of NFC in rations depress microbial growth and digestion of feed in the rumen, while excess NFC in rations causes acidosis and/or low milk fat tests.
Protein
Protein is required in animal rations to provide the supply of amino acids needed for tissue repair and synthesis, hormone synthesis, milk synthesis and many other physiological functions. Amino acids are supplied by the digestion of microbial protein, and by feed protein that escapes microbial breakdown in the rumen.
Protein requirements are expressed as crude protein (CP), either in amounts or as a percentage of the dietary DM. Crude protein is determined by multiplying the nitrogen content in a feed by the factor 6.25 (feed protein averages 16 percent nitrogen). Feedstuffs that contain nitrogen in a form other than proteins or peptides are called nonprotein nitrogen (NPN) sources. Urea and ammonium slats are examples of NPN sources. They have crude protein value, but they do not supply any amino acids directly. Nitrogen of NPN sources is utilized by ruminal microorganisms. They convert it into amino acid and use them for their growth. These microbes then pass into small intestine where they are digested and amino acids are released for absorption and utilization, the same way as amino acids released from the digestion of true proteins in feeds.
All feed protein sources are not degraded in the rumen to the same extent. Three protein terms describe the fate of dietary protein in the rumen:
Degradable intake protein (DIP) is the portion of feed protein broken down to ammonia or amino acids by the rumen microbes.
Soluble intake protein (SIP) is the portion of DIP that is rapidly degraded in the rumen. Generally, SIP is about half of the DIP.
Undegradable intake protein (UIP) is the portion of feed protein that is not degraded by the rumen microbes and remains intact as it passes through the rumen. Other terms for UIP include by-pass protein and escape protein.
Values for UIP, SIP and DIP can be expressed as either a percent of the dietary DM (for example, a feed may contain 17 percent CP and 6.8 percent UIP in the DM) or as a percent of the CP (for example, 40 percent UIP calculated by 6.8/17). The sum of DIP and UIP, expressed as percent of CP, must equal 100. Diets for high producing dairy cows should contain 19 percent CP with 38 percent of the CP as UIP, 62 percent as DIP and 30 percent as SIP; or 19 percent CP with 7.2 percent UIP, 11.8 percent DIP and 5.7 percent SIP in the dietary DM.
The optimal diet fed to dairy cattle will meet the nitrogen requirement of rumen micro-organisms for maximum synthesis of micro-organism protein and allow for maximum escape or bypass of high quality feed protein for digestion in the small intestine. Protein synthesis by rumen microbes will depend on feed intake, organic matter digestibility, feed type, protein level, and feeding system. Since 4.5 pounds of microbial protein synthesis per day is near the maximum, the remainder of the protein must be derived from UIP sources. Young, fast-growing heifers and high-producing cows may require additional UIP sources beyond their normal diet to meet their amino acid requirements. Excess protein, above requirements, is used as a source of energy.
Urea is a good example of NPN. Its use in dairy cattle feeding is limited by its lack of palatability and the animal’s ability to utilize it for protein synthesis. Its utilization is affected by the way it is fed, the availability of a source of the carbon compounds needed for protein synthesis and the level of protein of the total ration. Starches are a very effective source of carbon compounds for ruminants amino acid synthesis. Cellulose is less effective as it is degraded too slowly and simple sugars degraded too rapidly to be mass effective. NPN is not very effective utilized by high producing cows being fed relatively high levels of total ration protein (14-15% of the DM). It can however be more effectively utilized by lower producing cows being fed lower levels of total ration protein (up to 12 to 13% of the DM).
Minerals
Minerals are essential dietary constituents and required in relatively small quantities. On the basis of requirement minerals are classified as micromineral and macromineral. Macrominerals are those which are required in relatively large amounts while micro minerals are those which are required in small amount. Microminerals are also called trace elements.
Macrominerals
Sodium Chloride:
Sodium is an extracellular and potassium an intracellular cation, while chloride is associated with sodium as an extracellular anion. These minerals help in acid base balance along with bicarbonate ions, electrolyte balance, fluid balance and regulation of osmotic tension. Sodium and sodium chloride are usually provided in the form of common salt. However potassium chloride may also be used as a source of chloride, excessive levels of chloride without sodium or potassium can contribute to acidosis in dairy animals. The deficiency of sodium causes poor growth, poor feed utilization, dehydration and decreased cardiac output. The first sign of sodium deficiency is craving for salt manifested by licking of wood, skin, soil etc.
Potassium: Milk contains about 0.15% potassium. Heat stress increases the need for potassium because of its greater loss in sweat. Potassium deficiency does not normally occur since roughages supply sufficient potassium to meet the dairy animals requirements. The signs of severe potassium deficiency in lactating animal include a marked decrease in feed intake, loss in weight, decreased milk yield, pica, loss of hair glossiness, decreased pliability of the hide, lower plasma and milk potassium and higher haematocrit (PCV), potassium (3% or above) in every lush forages growing on high potassium soils in cool weather may cause both grass tetany and milk fever of lactating animals.
Sulphur: It is required for growth of hair, hooves and horn. Milk contains 0.03% sulphur, much of which is in the form of amino acids, methionine and cystine.
Magnesium: The adult animal body contains about 0.044% of magnesium and is closely related to calcium and phosphorus. About 70% of magnesium is present in bones, while the rest is in soft tissues and body fluids. Milk contains about 0.15% magnesium. Magnesium requirement increase with the level of milk production. Magnesium toxicity is not known to be a problem in dairy animals. Oil cakes and leguminous fodders are rich sources of magnesium. Tolerance level of magnesium in diary animals is 0.50 %.
Calcium: It is the major element present in animal body from 1 to 1.6%. More than 90% of body calcium is present in bones and teeth while the rest is found in soft tissues and body fluids. Whole milk contains about 0.12% calcium. Calcium serves a number of physiological functions in the body such as coagulation of blood, acid base balance, excitability of nerves, muscle tone, and activates enzymes like lipases, peptidases. Deficiency of Ca causes rickets in young animals and osteomalacia in adults. In addition slow growth, poor bone development, reduced milk yield and increase incidence of milk fever are also caused by calcium deficiency.
Phosphorus:It is the major intracellular anion found in animal body. Whole milk contains 0.09%. About 80% of the total body phosphorus is present in bones, 10% in combination with proteins, fats and carbohydrates. Deoxyribonucleic acid and ribonucleic acid which are required for gene expression and protein synthesis, contain phosphorus. As a component of phospholipid phosphorus forms the cell membrane structure and helps in absorption and transportation of lipid. Its deficiency leads to rickets, poor growth, arched back, muscular weakness and poor reproductive performance. Excessive phosphorus intakes may cause bone resorption, elevated plasma phosphorus levels and urinary calculi. High calcium, iron and aluminium in feeds predispose the animals to phosphorus deficiency.
Microminerals
Cobalt: Probably cobalt as such has no physiological function in animal body but as a component of vitamin B12 it plays an important role. It is utilized by the rumen microbes for the synthesis of vitamin B12. Deficiency of cobalt causes anorexia, anemia, progressive emaciation, rough hair coat, restlessness and decreased milk production.
Copper: Copper helps in utilization of iron, hemoglobin synthesis, maturation of RBCs, pigmentation of hair, myoglobin synthesis and bone formation. It is also a component of superoxide dismutase involved in antioxidation process. Thus protecting cells form any damage. A deficiency of copper results in anemia and depigmentation of hair. Black hair turns grey and red becoming yellow. Swelling of long bones, stiff joints, delayed oestrus and reproductive failure take place due to Copper deficiency.
Iodine:
Iodine is deficient in many hilly subhilly areas of Pakistan. The iodine uptake is also reduced by plants in summer months under tropical conditions and supplemental iodine above the requirement is beneficial to improve milk production in buffaloes. Goiter (an enlargement of thyroid glands) occurs in newborn calves if their mothers are fed iodine deficient ration. The necks of calves are also swollen. They are weak at birth or they are born dead. Calves may be born blind and hairless. Fertility is reduced in both sexes.
Iron:
Iron is essential because it is a constituent of hemoglobin, the oxygen carrier in the blood. It plays a key role in oxygen transportation and oxidative process. Deficiency symptoms are anemia, loss of appetite, depressed body weight gain and painful respiration even on slight exercise. The higher concentration of iron in feeds and fodders in tropical countries may hamper availability of phosphorus, Zinc , and copper.
Manganese:It is involved in several enzymatic systems required for metabolism of amino acids and nucleic acids, oxidative phosphorylation, synthesis of fatty acids, cholesterol and mucopolysaccharides. Manganese deficiency in calves leads to weak and twisted legs and enlarged joints.
Molybdenum:
Molybdenum is an indispensable component of enzyme xanthine oxidase which is found in milk distributed widely in animal tissue. Yet a deficiency of molybdenum has not been observed in cattle. Molybdenum is known largely for its toxic effects. It toxicosis is a practical problem in grazing cattle in many areas of the world. There is a antagonistic relationship between molybdenum and copper. Elevated dietary molybdenum increases both the animals requirements of copper and the amount of copper that causes toxicosis. Increased dietary copper can reduce the toxic effects of molybdenum. If the level of copper in the body is low, a lesser amount of molybdenum is toxic. High levels of both molybdenum and sulphur interfere with Cu absorption.
Selenium:
As a component of enzyme glutathione peroxidase selenium serves as an antioxidant. Like molybdenum, selenium was known for its toxic effects, before it was discovered to be an essential nutrient for ruminants. It is needed in trace amounts to prevent retarded growth, reproductive problem, retained placenta, while muscle disease and some mastitis problems. Selenium is closely associated with vitamin E. both selenium and vitamin E protect cells form the detrimental effects of peroxidation but each takes a different approach. Deficient or toxic selenium areas are widely scattered throughout the world.
Zink: Zink is associated with many enzymes as an essential component or activator and is responsible for metabolism of carbohydrates, lipids, proteins and nucleic acids. As a component of alcohol dehydrogenase, it helps in conversion of retinol to retinal and vice versa. Zink is adversely affected when excess quantities of calcium are present. Moderate excesses of zink are not toxic to dairy animals. Galvanized pipes and galvnanized buckets which are commonly used to provide water to dairy animals contribute zink along the way. Anorexia depressed growth feed intake and feed utilization, reduced testicular growth and development, loss of hair, scaly skin, unhealthy appearance and stiffness of joints are the signs of zinc deficiency.
Factor Affecting Mineral Requirement
The requirements of minerals are governed by many factors including:
Dietary concentration of the relevant mineral
Its chemical form and solubility
Its status in animal body
Breed, age, physiological state of the animal
Relative concentration of other interacting minerals
Loss of body fluid due to trauma
Infection and disease
Vitamins
Vitamins are complex organic compounds that are required in traces by various farm animals for maintenance, normal growth, production, reproduction and health. Vitamins are classified as fat soluble vitamins and water soluble vitamins. Fat soluble vitamins include A, D, E and K while water soluble vitamins are vitamins B, (B1, B2, B6, B12), choline, pantothenic acid, folic acid and vitamin C.
Vitamin A:Vitamin A is the most important of all vitamins. It is not found in plants and strictly a product of animal metabolism. Its precursor is carotene which is present in plants. Animal body has the ability to transform carotene into vitamin A. Vitamin A is required for the normal functioning of the osteoclasts and osteoblasts in the epithelial cartilages. It is important for the vision of animal.
Vitamin D:
Vitamin D is significant for regulating calcium and phosphorus metabolism. It promotes intestinal absorption. Sources of vitamin D are fish oils, eggs, milk and liver. Vitamin D can be formed in body by exposure to sun.
Vitamin E: Vitamin E is an antioxidant associated with selenium. It stimulates the immune system and reduces the incidence of oxidized flavor when consumed at high levels. It may aid in protection against white muscle disease caused by a deficiency of selenium. It is also involved in formation of biological membranes.
Vitamin K: Vitamin K functions as a stimulant to blood coagulation. Either vitamin K1 (phylloquinone) or vitamin K2 (menaquinone) meets the needs of dairy animals. Green, leafy materials of any kind, both fresh and dry, are good sources of vitamin K1. Normally, vitamin K2 is synthesized in large amounts in the rumen; therefore, dietary supplementation is not recommended. When animal consumes mouldy sweet clover hay which is high in dicumarol, blood coagulation may be impaired followed by general haemorrhage. This syndrome commonly called sweet-clover disease or sweet-clover poisoning responds to treatment with vitamin K.
Vitamin B-Complex:The B-complex group of vitamins includes thiamin (B1), riboflavin (B2), vitamin B6 (pyridoxine), biotin, choline, folic acid, niacin (nicotinic acid, nicotinamide), pantothenic acid (vitamin B5), vitamin B12 (cobalamin, cyanocobalamin). Recent evidence suggests a need for supplemental niacin under certain conditions, and possibly supplemental choline and thiamin in the case of mature dairy animals, for which microbial synthesis and quantities in feeds may be inadequate, especially during diseased conditions or periods of stress. Dairy animals of all ages have a physiological need for most of the B vitamins, especially biotin, choline, niacin, pantothenic acid, riboflavin, thiamin, vitamin B6, and vitamin B12. In young calves, deficiency signs have been noticed when there is inadequate intake of these vitamins, but even without a functioning rumen, their needs for these B vitamins appear to be met when they are fed whole milk. However, when young calves are fed milk replacers, it is advisable to ascertain the adequacy of vitamin intakes until their rumens are functional.
Thiamin (Vitamin B1):
A deficiency of thiamin in the calf may cause polioencephalomalacia, characterized by lack of muscular coordination, convulsions, progressive blindness, listlessness and sudden death, usually preceded by diarrhoea and dehydration. This condition is mainly found in dairy animals fed high concentrate rations, and it has been linked to increased microbial thiaminase activity and the production of thiamin analogue in the rumen.
Riboflavin (Vitamin B2):
Since the rumen bacteria synthesize riboflavin in adequate amounts, it is, therefore, not a dietary essential in ruminants. Also, it is present in many feedstuffs. In the calf, its deficiency is characterized by hyperemia (presence of blood in the mucosa of the mouth), lesions in the corners of the mouth and along the edges of the lips, loss of hair, especially on the belly, and excess salivation. Riboflavin plays role in the intermediary metabolism and assimilation of nutrients. It helps form flavoprotein enzymes and coenzymes, which act in metabolic release of feed energy in the body.
Vitamin B6 (Pyridoxine, Pyridoxamine, Pyridoxal):
Vitamin B6 is considered important in several enzyme systems concerned with metabolism of proteins. Tryptophan will not be completely metabolized in the absence of this vitamin. Its deficiency has been produced in calves fed a synthetic diet. The deficiency has been characterized by loss of appetite, cessation of growth, and epileptic seizures in some, but not all. Calves respond to vitamin B6 therapy if it is initiated in the early stage of the disease.
Biotin:
Biotin is also a part of many enzyme systems in intermediary metabolism. In ruminants, microbial synthesis inrumen takes care of dietary needs. However, in calves, its deficiency has been characterized by paralysis of the hind quarters. Signs of deficiency did not develop when synthetic milk was supplemented with 9 micrograms/kg of feed.
Niacin (Nicotinic Acid, Nicotinamide):
Niacin forms a part of two important co-enzymes (NAD and NADH). These enzymes are involved in a series of reactions in the metabolism of all nutrients, in which biological oxidation-reductions take place. Niacin is required by the young preruminant calf. In addition, rumen microbes may not synthesize adequate amounts of niacin to meet needs of high producing animals in early lactation. The major reason for improvement in milk production that occurs with added niacin may be related to the role of niacin in carbohydrate and lipid metabolism and resultant decrease in ketosis. Niacin may also influence rumen fermentation, as evidenced by greater microbial protein synthesis and increased levels of rumen propionate with niacin supplementation. When dairy animals are fed heated soybean meal, rumen response to niacin is greater than when they are fed unheated soybean meal.
Folic Acid (Folacin):
Folic acid plays an important role in intermediary metabolism. Due to its synthesis in the rumen, it is not a dietary essential.
Pantothenic Acid (Vitamin B5):
Pantothenic acid forms part of co-enzyme A, which is essential for the nutrients to enter the tricarboxylic acid cycle in metabolism. Its deficiency in calves is characterized by a scaly dermatitis around the eyes and muzzle, loss of appetite, diarrhea, weakness, inability to stand, and convulsions. Its deficiency is unlikely to occur in animals with normally functioning rumens (microbial synthesis).
Vitamin B12 (Cobalamin):
Vitamin B12 deficiency has been produced in preruminant calves by feeding them a diet having no animal protein. Signs of deficiency included poor appetite and growth, muscular weakness, and poor general condition.
Vitamin C (Ascorbic):A deficiency of vitamin C can reduce the ability of neutrophils to migrate to the site of inflammation allowing for increased oxidative damage to the neutrophils and reduced production of major anti microbial agent hypochlorous acid. Ascorbic acid may also modulate the immune system via its role in regulation of hormones associated with stress. There is a close synergism between ascorbic acid and vitamin E is enhancing neutrophil function and minimizing free radical damage. Vitamin C can quench free radicals and there by protect the structural integrity of the cell of immune system.
Vitamin c is synthesized in the rumen of buffalos and cattle. It is in generally assumed that endogenously produced ascorbic acid is sufficient to meet the metabolic demands of ruminants. Under specific environmental and physiological conditions, the amount of ascorbic acid produced by the animal may be insufficient to meet its requirement.
Dairy Cow Nutrition
Dairy cow nutrition varies with phases of lactation and gestation. Lactation period of dairy cow is divided into five phases:
Phase 1. This is phase of early lactation consists of early 70 days postpartum. This is the period during which milk production increases rapidly, peaking at 6 to 8 weeks after calving. During this phase nutrient requirements are not fulfilled because feed intake does not keep pace with nutrient needs for milk production, especially for energy, and body tissue will be mobilized to meet energy requirements for milk production. Ration adjustment is an important management practice during early lactation. Fiber level in the total ration should not be less than 18 percent ADF, 28 percent NDF. Forage should provide at least 21 percentage units of NDF or about 75 percent of the total NDF in the ration. Physical form of the fiber is also important. Normal rumination and digestion will be maintained if greater than 20 percent of the forage is 2 inches in length or longer. Chopping (less than 3/8 inch theoretical length of chop—TLC), grinding, and/or pelleting all reduce physical form of fiber and its effectiveness to stimulate rumination. Protein is a critical nutrient during early lactation. Rations may need to contain 19 percent or more crude protein to meet requirements during this period.
Nutrients requirements must be met to avoid the problems like ketosis or low peak production. Loss of 1 litre milk in peak production leads to loss of 100 litres milk for lactation.
Phase 2. This phase is from 70 to 140 days postpartum during which animal reaches peak DM intake. During this phase animal is at its peak production and this production should be maintained as long as possible. Animal should be provided high quality forage along with concentrate.
Phase 3. This period is of mid to late lactation i.e. 140 to 305 days postpartum. During this phase milk production is declining and the cow is pregnant. Animal require nutrients for milk production and replace body weight lost during early lactation. Lactating cows require less feed to replace a pound of body tissue than dry cows. Young cows should receive additional nutrients for growth (2-year-old, 20 percent more; 3-year-old, 10 percent more than maintenance).
Phase 4. Phase 4 is dry period that covers 60 to 14 days before parturition. This is a critical phase of the lactation cycle. A good, sound nutritional management during this phase may lead to high milk yield during the following lactation and minimize metabolic problems at or immediately after parturition as animal is preparing for next lactation during this phase.
Dry cow requirements include body maintenance, fetal growth, and replacing any additional body weight not replaced during phase 3. Nutrients requirements during this phase are lowest. Animal should be provided 1.8-2.1% DM of body weight. A minimum of 12 percent CP in the DM is recommended. Concentrate requirements druing this phase are less. Give 1 Kg Concentrate per day to maintain ruminal movements and microflora. A high forage (85%) content is thought to be beneficial to maintain maximum rumen volume and motility. Due to higher chewing activity more saliva is produced, which will buffer the rumen and help maintain a higher rumen pH which will allow rumen wall lesions to recover from high gain rations during lactation.
Calcium and phosphorus requirements should be met, but large excesses must be avoided. Dry cow rations above 0.6 percent calcium and 0.4 percent phosphorus (DM basis) have substantially increased milk fever problems. Adequate amounts of vitamin A, D, and E in rations to improve calf survival and lower retained placenta and milk fever problems should be proved. Trace minerals, including selenium for most producers, should be adequately supplemented in dry cow diets.
Phase 5. This period is called transition period or close up period which includes last two weeks of parturition. Nutritional requirements for fetal growth are higher during this phase. Good nutritional planning is required during this phase to get high milk production after parturition. DMI intake decreases and energy requirement increases to meet fetal growth so high energy diets should be provided. Mineral and vitamin supplementation is also required. Ingredients like concentrate to be used during lactation should be started in small amounts during this phase as it reduces the nutritional stress after parturition. CP % should be exceeded upto 15%. Feeding some of additional protein in the form of undegradable protein may be beneficial in supplying amino acids for fetal growth. Fat content in the ration should be limited as high fat feeding will depress DM intake. In case of problem of edema salt should be removed from the ration.
