Previous Year Questions(Solved) | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Q1: Write short notes on: Role of Cobalt in Ruminant Nutrition. 
Ans:
Progress in understanding the mode of action of cobalt in the animal organism was slow until the discovery that the antipernicious anemia factor in liver, subsequently designated as vitamin B₁₂ is a cobalt compound containing almost 4 per cent of the metal Within three years after this discovery, complete remission of all signs of cobalt deficiency in lambs was secured with parenteral injections of vitamin B₁₂ Thus, it is proved that cobalt deficiency in ruminants is actually a vitamin B₁₂ deficiency brought about by the inability of the rumen micro-organisms in the absence of dietary cobalt to synthesize sufficient vitamin B₁₂ to meet the need of ruminant tissues for this vitamin. The other function of cobalt in animal nutrition has so far been demonstrated as the activating ion in certain enzyme reactions. Cobalt deficient animals virtually starve There is gradual wasting. In sheep, wool becomes straggly, rough and severe anemia develops with almost complete absence of appetite. As the condition becomes advanced, the animal becomes dull, listless and the skin around the eyes and the mouth becomes blanched. The O₂ carrying capacity of the blood gets reduced and the blood volume also is reduced. There is total absence of body fat. Instead, liver becomes fatty. Cobalt and vitamin B₁₂ decline to subnormal levels in the liver and the kidneys, which are the main sites of vitamin B₁₂ storage. The level of B₁₂ in the blood also is reduced.

Q2: Importance of Vitamin A in animal nutrition. (Paper I, Section B, Q. (c), CSE, 1986)
Ans:
Vitamin A is a dietary essential in all animals. The need of Vitamin A in farm animals is met by carotene which is normally present in plant kingdom, the chief source of food for the animal. The retina of the eye contains a protein known as rhodopsin or visual purple which changes the light energy into nerve impulse. Rhodopsin is bleached in light but is regenerated in the absence of light. Rhodopsin is a protein and Vitamin A complex which when bleached is converted into a light yellow compound known as retinine or Vitamin A - aldehyde. Retinine then breaks up into protein and Vitamin A. The protein then reunites with Vitamin A reservoir to synthesize rhodopsin. In the case of Vitamin A deficiency the resynthesis of rhodopsin is checked so that visibility of the eye is affected resulting in night-blindness. There are various eye symptoms caused in different species. Xerophthalmia occurs in children and rats due to Vitamin A deficiency. In cows copious lacrimation results. In chicken the tear glands dry up and eyelids stick together. Respiratory infections are common in Vitamin A deficiency, since the lining of the respiratory tract is affected and this fails to prevent bacterial infection. Sterility, renal calculi and intestinal inflammation occur in Vitamin A deficiency. Gastro-intestinal disorders and diarrhea are caused in Vitamin A deficiency. Skin disorders as dryness, roughness and eruptions of skin also result. Vitamin A is responsible for the normal development of bones. Bones are deformed if Vitamin A is deficient. Teeth are also affected. Abnormal development of spinal and other bones affect degeneration of nerves due to pressure on them. The narrowing of bone canal causes constriction of optic nerve, causing blindness in calves. Avitaminosis of vitamin A causes deafness in dogs due to injury of the auditory nerve. Bone changes also cause incoordination of muscle and other nervous symptoms in sheep, swine and cattle, deficient in vitamin A They also increase the cerebrospinal pressure. Vitamin A deficiency causes congenital malformation in some of the soft tissues e.g., birth of pigs without eyeballs. Egg production decreases and clutch size increases during egg production in hens. Poor production is accompanied by poor hatchability.

Q3: Significance of trace elements in animal nutrition.
Ans: There are certain elements which occur in the animal body in traces but exert a considerable influence on animal's health and production. They are called trace elements or microelements. They are measured as parts per million (ppm). The important trace elements include molybdenum, selenium, and fluorine though chromium, tin, and vanadium are also other trace elements essential for normal growth in some animals. Iron is a component of hemoglobin which helps in the transport of oxygen. It is a component of various enzyme systems. Iron deficiency is not common in ruminants and poultry but is common in pigs, producing anemia. Copper is present in more than a dozen enzymes in the animal body and its role extends from utilization of iron to pigmentation of skin. Deficiency symptoms include anemia, depressed growth, bone disorders, etc. 'Stringy wool' appears in sheep in copper deficiency. Cobalt is required for synthesis of vitamin B12 and cobalt deficiency symptoms are actually vitamin B12 deficiency symptoms. Thyroid gland contains more than half of the iodine contained in the whole body. It is incorporated as thyroxine, a hormone secreted by the thyroid gland. Deficiency of iodine results in reduced production of thyroxine and goiter is produced consequently. Iodine deficient pregnant animals produce hairless, weak or dead young. Manganese is required for proper formation of bones, development and functioning of the reproductive system and normal growth of animal. Deficiency causes slipped tendon and poor hatchability in poultry. Zinc deficient diets cause stunted growth, skin diseases, lowered feed efficiency and delayed sexual maturity in general and lowered fertility and milk production in cows. Molybdenum is important for its toxicity when in excess. Its deficiency produces 'teartiness' in ruminants. Selenium is required in traces along with vitamin E for metabolic functioning of animals. Vitamin E can partially replace selenium. Fluorine is required in traces for skeletal development. Deficiency causes dental caries. Fluorine is a cumulative poison causing cavities in teeth and bone and joint abnormalities. Trace elements are required in traces for development and production in livestock and at the same time their toxic effect is highly significant when taken in excess. Hence, care should be taken to see that they are given only the required (traces) amounts and never in high concentrations.

Q4: Write short notes on: Role of B Vitamins in metabolism of energy and protein.
Ans:
All the vitamins of B group are water-soluble and many of them are components of various enzyme systems. All the vitamins of B group are essentially required by the animal cells which cannot synthesize any of the vitamins except niacin and choline. Thiamine (Vitamin B1) after absorption from the small intestine is carried to the liver where it is phosphorylated in the presence of ATP and forms coenzyme, cocarboxylase. There are two such coenzymes which contain thiamine, viz., thiamine pyrophosphate (cocarboxylase) and lipothiamide. Thiamine is therefore involved in the decarboxylation of a-keto acids such as pyruvic and a-ketoglutaric. Riboflavin (Vitamin B2) functions in the body as a constituent of many enzyme systems. Warburg's yellow enzyme is a combination of riboflavin with phosphoric acid and a protein. In the breakdown of glucone to provide energy, one or more yellow enzymes are required along with coenzymes I or II. Riboflavin is also a part of xanthine oxidase which is responsible in purine metabolism and of D-amino acid oxidase which functions in the final stages of protein metabolism. Thus, this vitamin plays an important role in the release of energy and assimilation of nutrients. Nicotinamide is the amide derivative of niacin (nicotinic acid). In the body, nicotinamide is the physiologically active form of the vitamin, niacin. Nicotinamide is found in coenzymes I and II. They function in the oxidation-reduction system by accepting the hydrogen atoms from substrates and transferring this for the other hydrogen acceptors. All the three forms of pyridoxine (Vitamin B6) are converted into pyridoxal phosphate, which is an active coenzyme of various enzyme systems including the decarboxylation and transamination of the amino acids, which helps in tissue transamination and catalysis, and the transfer of the amino group of glutamic acid and certain other amino acids to keto acid forming new amino acids. This helps in the biological synthesis of tryptophane from serine and indol. In rats and swine, it is necessary for the complete metabolism of tryptophane. Pantothenic acid functions as a part of coenzyme A in various metabolic processes and is a component of the enzyme which is required for acetylation of choline for the formation of acetylcholine and functions in acetate metabolism and other biochemical processes. Biotin is a component of ADP biotin enzyme complex and is responsible for carboxylation reactions. Choline furnishes methyl group for transmethylation in tissue metabolism. In the absence of enough amounts of methionine, choline furnishes methyl group to the non-essential amino acid homocystine to convert it to methionine. It also serves as a constituent of many phospholipids and phosphatids. Acetylcholine helps in the transmission of nerve impulses and reduces the blood pressure. It also helps in fat metabolism. Folic acid functions in certain enzyme systems including that concerned with oxidation of tyrosine. It also helps in the synthesis and metabolism of nucleic acids and their derivatives. Thus, the various B complex vitamins help in the metabolism of energy and protein.

Q5: Name the major and minor mineral elements considered essential for livestock. What are the functions of calcium and phosphorus in the animal body? Write a note on the interrelationship of calcium, phosphorus and vitamin D in nutrition.
Ans:
Essential mineral elements are those minerals which have been proved to have a metabolic role in the animal body. These are classified into two categories: (i) Macroelements and (ii) Microelements based on their concentration in the body. The concentration of macroelements (major elements) is expressed in terms of percentage while the concentration of microelements (commonly known as trace elements) is expressed in terms of parts per million (ppm) since their concentration is very low in plants and animals.

The major elements or macroelements are Calcium, Phosphorus, Potassium, Sodium, Sulfur, Magnesium, and Chlorine.

The microelements or trace elements are Manganese, Iron, Copper, Iodine, Zinc, Cobalt, Molybdenum, Chromium, Fluorine, and Selenium.

Over the years, reports have appeared showing growth response to few other trace elements. Six elements, aluminum, bromine, boron, chromium, tin, and strontium were reported to give significant growth response when added to the diet of chickens. Subsequently, Tin, Nickel, Vanadium, and Silicon appeared to be likely essential for animals though clear-cut data are not available. These elements may be considered as minor mineral elements.

The functions of calcium in the animal body are:

1. Bone formation including teeth and growth.
2. Clotting of blood.
3. Regulation of heart and working of muscles.
4. Maintenance of acid-base equilibrium.
5. Control of irritability of the neuromuscular system.
6. Maintenance of selective permeability of cell membrane.

The following are the functions of phosphorus in the animal body:

1. It is a constituent of bone and teeth.
2. It is a constituent of the high-energy compound ATP and so is necessary for energy transductions, essential for cellular activity.
3. The oxidation of carbohydrates leading to the formation of ATP requires phosphorus.
4. Phospholipids are constituents of cellular membranes and are active determinants of cellular permeability.
5. Phosphorylated compounds are necessary for the synthesis of DNA and RNA.

Interrelationship of Calcium, Phosphorus, and Vitamin D in animal Nutrition: Adequate nutrition of calcium and phosphorus depends upon three factors: an adequate supply of these minerals, a suitable ratio between these elements, and the presence of vitamin D. These factors are interrelated to each other. The most appropriate ratio between calcium and phosphorus for proper nutrition is between 2:1 and 12, although nutrition may be possible beyond these limits. A ratio beyond this (say 10:1) may also mean adequate amounts of phosphorus and calcium but the utilization will be poor. The same is true when the ratio is reversed. The ratio is of less importance with adequate amounts of vitamin D in the ration as it affects more efficient utilization of these minerals. The utilization of calcium and phosphorus is very poor in the complete absence of vitamin D although other factors may be optimum. The relative importance of these factors varies considerably in different species depending upon the physiological function in question. It has been found by De Luca (1964) that vitamin D stimulates the incorporation of phosphorus into phospholipids of intestinal mucosa. Even after calcium and phosphorus have been absorbed, they may not be deposited in the bones but instead, they may be excreted immediately if vitamin D is not present. Thus, net absorption of calcium and phosphorus, i.e., the amount which actually remains in the body, depends on the presence of vitamin D. Vitamin D or Vitamin D derivatives intensify the diffusion of calcium ions across the intestinal wall by counteracting the factors which reduce the concentration of Ca2+ or by increasing the permeability of the membrane of intestinal epithelium. A special calcium transport system is formed or initiated in the presence of vitamin D.