Animal husbandry

ANIMAL BREEDING

A group of animals related by descent and similar in most characters like general appearance, features, size, configuration etc. are said to belong to a 'breed'. Animal breeding is producing improved breeds of domesticated animals by improving their genotypes through selective mating.

Objectives of Animal Breeding:

The main objectives of animal breeding are: (i) Improved growth rate, (ii) increased production of milk, meat, egg, wool, etc., (iii) superior quality of milk, meat, eggs, wool, etc., (iv) improved resistance to various diseases, (v) increased productive life and (vi) increased or, at least, acceptable reproduction rate, etc.

Methods of Animal Breeding : Two methods of animals breeding are: inbreeding and outbreeding (based mainly on breeding work done with cattle).

1. Inbreeding.

When breeding is between animals of the same breed for 4-6 generations, it is called inbreeding. e.g. between breeds of cows, buffaloes, poultry etc.

Inbreeding may be explained by taking an example of cows and bulls.

Superior cows and superior bulls of the same breed are identified and mated.

The progeny obtained from such mating are evaluated and superior males and females are identified for further mating.

A superior female, in the case of cattle, is the cow that produces more milk per lactation.

On the other hand, a superior male is that bull which gives rise to superior progeny as compared to those of other males.

Inbreeding, as a rule, increases homozygosity.

Thus inbreeding is necessary if we want to develop a pureline in any animal.

Inbreeding exposes harmful recessive genes that are eliminated by selection.

It also helps in accumulation of superior genes and elimination of less desirable genes.

But continued inbreeding reduces fertility and even productivity.

This is called inbreeding depression.

In this condition, the selected animals of the breeding population should be mated with superior animals of the same breed but those which are unrelated to the breeding population.

2. Outbreeding.

Outbreeding is the breeding between the unrelated animals which may be between individuals of the same breed (but not having common ancestors) or between different breeds (cross breeding) or different species (interspecific hybridization).

(i) Outcrossing. It is the mating of animals within the same breed but not having common ancestors on either side of their pedigree up to 4-6 generations. The offspring of such a cross is called an outcross. Outcrossing is the best breeding method for animals that are below average in productivity and milk production, growth rate in beef in cattle etc. Sometimes only one outcross helps to overcome inbreeding depression.

(ii) Cross-breeding. In cross-breeding, superior males of one breed are mated with superior females of another breed. Many new animal breeds have been developed by this strategy. It gives better breeds. Cows of an inferior breed may be mated to bulls of a superior breed to get better progeny. Hisardale is a new breed of sheep developed in Punjab by crossing Bikaneri ewes and Marino rams.

(iii) Interspecific Hybridisation. In this approach, male and female animals of two different species are mated. The progeny obtained from such a mating are usually different from both the parental species. But in some cases, the progeny may combine desirable characters of both the parents. Mule is produced from a cross between female horse (mare) and male donkey. Mules are sturdier than their parents and are well suited for hardwork in mountainous regions.

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Controlled Breeding Experiments :

These are carried out using artificial insemination and Multiple Ovulation Embryo Transfer Technology (MOET).

1. Artificial Insemination (AI) :

The semen of superior male is collected and injected into the reproductive tract of the selected female by the breeder.

The semen can be used immediately or can be frozen for later use.

When a bull inseminates a cow naturally, approximately 5 to 10 billion sperms are deposited in the vagina.

However, when semen is deposited artificially, considerably fewer sperms are required to achieve conception.

Therefore, artificial insemination is very economical.

The spread of certain diseases can be controlled by this method.

2. Multiple Ovulation Embryo Transfer (MOET) :

In this method, hormones (with FSH-like activity) are given to the cow for inducing follicular maturation and super ovulation.

Instead of one egg, which they usually give per cycle, they produce 6-8 eggs.

The cow is either mated with a best bull or artificially inseminated.

The embryos at 8-32 cell stage are recovered and transferred to surrogate mothers.

The genetic mother is available for another super ovulation.

MOET has been done in cattle, sheep, rabbits, buffaloes, mares, etc.

High milk giving breeds of females and high quality (lean meat with less lipid) meat giving bulls have been bred successfully to obtain better breed in a short time.

Animal husbandry is the science of rearing, improvement and caring of domesticated animals.

Although the word "Animal" includes any of the various organisms belonging to the kingdom Animalia but when we use it in animal husbandry, we mean only those domesticated animals which are reared mostly for economic or for recreation purposes, such as cattle, buffalo, sheep, goat, camel, pig, horse, etc.

It also includes poultry farming and fisheries.

Since long time, animals like bees and silkworm have been used by humans.

All above mentioned livestock (animals kept for use or profit) has been used by humans for products like milk, eggs, meat, wool, silk, honey, etc.

The word 'husbandry' means the management of domestic affair.

The term used in connection with animal husbandry includes proper feeding, breeding, health care, housing etc.

Domestication of animals probably began during the 'hunting and gathering' phase of human civilisation.

As humans realised the importance of domesticating animals for use as beasts of burden and as sources of milk, meat, leather and fur, methods of improvement through selective breeding were used.

Curiosuly, Old World Agriculture employed animals.

While there is little evidence of the use of animals in the primitive agriculture of the New World.

Most of the useful animals raised today have evolved from their wild ancestors.

One of the earliest animals to be domesticated was the dog.

Starting from a few basic types, the wild dog, the wolf and the jackal, man has produced an amazing variety of breeds. The Eskimos still use huskies to draw sledges.

Cattle livestock :

Buffalo in India, termed 'water-buffalo' in the western literature, constitutes the most important species of livestock in India.

They serve as the primary source of milk -the only dietary animal protein for a majority of Indians.

The cattle are used to draw water from wells.

Their dung is used as fuel and for the generation of biogas.

India happens to be one of the largest exporters of leather goods made from cattle hide.

Horns, hooves and bones are used to prepare cattle feed and fertilizers.

Indian cattle are hardy and highly resistant to major diseases.

Bulls from India are used for crossbreeding with European and American varieties.

The best Indian cattle breeds are found in the drier parts of the country.

There are 26 breeds of cattle and seven breeds of buffaloes which differ in their body colours, horns and shape of forehead.

The family of domestic cattle is Bovidae.

There are two main groups of bovidae (domestic cattle) i.e.,

(i) Bos Indicus found in India and Africa . They are also called Zebu Cattle or humped cattle.

(ii) Bos taurus are found in Europe and North America and are non humped cattle.

The zebu is characterised by

(i) presence of prominent hump,

(ii) upright horns,

(iii) a long face,

(iv) drooping ears and

(v) large and slender legs. In the U.S. Zebus are called Brahman cattle.

The cattle breeds are classified into three groups.

(i) Milch breeds: The cows of these breeds are good milk producers, however, bullocks are of poor quality.

(ii) Draught breeds : The bullocks of these breeds are good for working but cows are poor milk producers.

(iii) General utility breeds (Dual-purpose breeds) : The cows of these breeds are good milk producers and the bullocks are good draught animals. They are intermediate between milch and draught breeds.

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Cross Breeds

1. Karan Swiss: This breed has been evolved at the National Dairy Research Institute, Karnal in Haryana, by breeding the Sahiwal cows with the semen of Brown Swiss bulls imported from U.S.A.

2. Sunandini: This breed originated in Kerala by crossing the local non-descript cattle with Jersey, Brown Swiss and Holestein-Friesian breeds.

3. Karan Fries: The breed has got its origin at the National Dairy Research Institute Karnal, out of crossing between Tharparkar and Holstein-Friesian.

Some exotic (foreign) breeds of cattle (Bos taurus) that are used for cross-breeding purpose in India.

Compared to cows, buffaloes (Bubalus bubalus) generally yield more milk of high fat content.

They also have greater disease resistance and longevity.

The milk yielding capacity of buffaloes is three times more than cows. Buffalo milk is superior to cow's milk in fat content as well as minerals.

CATTLE MANAGEMENT AND FEEDING

1. India has about 227 million cattle and buffaloes. In terms of sheer numbers, India ranks fifth in the world. However, in milk production, India figures very poorly. Cattle management practices vary in different parts of the country depending upon climatic conditions. India is lowest in milk yield per cow.

Feeding: Ninety percent livestock subsists on grazing in public and government-owned lands and forests.

2. The prepared feed given to them is classified into :

(i) Roughages which include fodder, silage, hag and straw. This feed has a high fibre content.

(ii) Concentrates which include cereals, millets, forage crops with high leaf protein and oil cake, oil seeds, and animal by-products. Although low in fibre content, the concentrates have high nutrient value and digestibility. Minerals and vitamins are added to the feed of high yielders. The proportion of balanced feed differs for the young and the adult animals.

Cattle-Breeding

1. In the villages, a few good pedigree bulls are selected on the basis of draught ability and permitted to graze with the cows to bring about random breeding. Bulls not selected for breeding are castrated when young and converted to bullocks. They are the main source of animal draught power in India.

2. Mature cattle having more than 3 years of age should be used for breeding. The best local cows with a good milk yield should be mated with a pure breed exotic bull which should have high genetic potential. One bull is usually enough for 60 to 70 cows.

3. About 10 to 60 per cent cows are artificially inseminated by semen collected from high quality bulls. Artificial insemination ensures good quality progeny and is also economical as semen from a single bull can inseminate several thousand cows. Average gestation period of the cow is 280 days. The length of gestation of buffaloes varies, influenced by breed and environment, between 276 and 340 days, but on an average, it lasts for 310 days or 10 months, in contrast to the cow with an average gestation of 280 days or 9 months.

4. An average cow or buffalo produces 8-10 calves during its productive life time : Generally only one ovum is fertilized at a time. Selective breeding, progeny testing and improvement take longer time in the livestock than in annual food crops. With the exception of certain Indian breeds which have been maintained for good yield, the majority of Indian cattle have been on marginal inputs and are infertile and poor milk yielders. Research on the cause of infertility led to the use of pregnant mare serum gonadotropin to augment fertility in sterile cows and to induce lactation immature females by implantation of stilbesterol tablets.

5. Artificial Insemination (AI). It involves the insemination of the semen of superior bulls of exotic or indigenous breeds into the native cows. The semen should be deposited either deep in the cervix or at beginning of the body of the uterus. When insemination is performed deep in the cervix, spermatozoa are likely to live longer in the cervix than in the uterus. Deposition of semen in the vagina results in dilution, contamination and lowered conception rate. When a bull inseminates a cow naturally, approximately 5 to 10 billion spermatozoa are deposited in the vagina. However, when semen is deposited artificially into the cervix considerably fewer sperms are required to achieve conception. Therefore, artificial insemination is very economical. Semen collected from a single superior bull can be used for fertilizing many cows. Semen from desired bull located at distant places can be used. The spread of certain diseases can be controlled by this method. Artificial insemination was first introduced in India at Indian Veterinary Research Institute, Izzatnagar, Bareilly, Uttar Pradesh.

6. To increase the milk yield, Indian cows are cross-bred with European breeds like Holstein, Brown Swiss, Jersey, Red Dane and others. The Karanswiss and Sunandini are the breeds developed through cross-breeding at the National Dairy Research Institute, Karnal , and in Kerala, respectively.

7. Super Ovulation and Embryo Transplantation: It is also called as MOET (Multiple ovulation and embryo transfer) A pedigreed bull and a high production cow are chosen to produce super milch cows. Superovulation is induced by hormone injection. After artifical insemination, 4 to 10 embryos are collected at a time. Each embryo is then transplanted into a 'carrier' cow (surrogate mother). Such embryo transplants can also be carried out in sheep, goats, and other livestock. By deep freezing (-196^QC), it is possible to preserve seven days old foetuses for several years to be used when needed. An embryo can be cut into two, to obtain homozygotic twins. The most beneficial outcome of embryo transplantation is the selection of high quality bulls for genetic upgrading. India has launched research using the above-mentioned techniques.

Use of Buffaloes

Milk: Buffaloes provide milk with all the essential nutrients. It has bigger size fat globules. The milk is rich in calcium and phosphorus and low in sodium and potassium. Buffalo milk is almost free from carotenoids (golden yellow in colour) due to conversion of all carotenoid materials into vitamin A (colourless by the liver cells). That is why buffalo milk and ghee is white whereas ghee made from cow milk is golden yellow in colour because of incomplete conversion of carotenoids into vitamin A inside liver cells which appears in cow milk.

Cattle Diseases

Most Zebu cattle (domesticated cattle, Bos indicus) are resistant to diseases like Rinderpest or cattle plague, foot and mouth and other bacterial and viral diseases.

Rinderpest has been controlled through a National Programme.

Vaccination is given to highly productive herds.

Domesticated animals suffer from a variety of diseases.

In animals, disease may be defined as a state of discomfort associated with an abnormal function of the animals body.

Diseases may be caused by mutant genes (genetic diseases), improper nutrition or pathogens.

Genetic diseases are strictly selected against during animal breeding.

Generally, animals are raised on properly balanced diets to avoid nutritional disorders and to ensure optimum performance.

Domesticated animals suffer from diseases caused by (a) viruses, (b) bacteria, (c) protozoa, (d) fungi, and (e) animals, like worms.

Such diseases are commonly known as infectious diseases because they are caused by pathogenic infections.

Many of the infectious diseases are known as contagious diseases since they spread to healthy animals by contact with diseased animals, or with materials that were in direct contact with the diseased animals.

Some of the infectious diseases may spread to humans from the animals, e.g. anthrax.

Infections can occur through skin, digestive tract, respiratory tract, conjunctiva, urogenital tract, placenta, umbilicus, udder, teats and egg.

It is a good policy to implement measures for the prevention of infectious diseases, some of which are as follows.

(i) Isolation of animals suffering from or suspected to be infected with an infectious disease

(ii) Proper disposal of the carcass and all materials that were in contact with the diseased animals(s).

(iii) Proper cleaning and disinfection of the animal house and other materials that were in contact with diseased animal(s).

(iv) Transfer of healthy animals to a pasture other than that used by diseased animal(s).

(v) Vaccination of animals.

(vi) Injection of antiserum into healthy animals whenever an epidemic is expected.

(vii) The authorities of the veterinary department should be immediately informed of cases of infectious diseases. This will allow them to initiate measures to prevent the spread of these diseases.

Bacterial Diseases

Animals suffer from several bacterial diseases. For example, cattle suffer from anthrax, mastitis, pneumonia, etc.

1. Anthrax:

Anthrax is caused bythe bacterium, Bacillus anthracis.

This disease is contagious and affects cattle, buffaloes, horse, sheep and goats; it can also spread to human beings.

In animals, anthrax spreads through contaminated food, water and pastures.

Symptoms and diagnosis:

In very acute cases, there is increased respiration, and blood-mixed foamy discharge from mouth, nose and anus.

In such cases, the infected animals may die within minutes.

But in subacute and chronic cases, the infected animals have high fever (up to 41.1ºC), and increased pulse and respiration rates.

There is discharge of black, shiny and foamy material from natural openings of animals.

The infected animals die within 2 to 3 days.

The anthrax bacterium uses up the oxygen carried by the animal blood.

As a result, the animals die due to a lack of oxygen.

Disease diagnosis can be confirmed by microscopic observation of the the bacterium in the blood of patients, or by culturing the bacterium present in the blood on a suitable medium.

Treatment:

In the case of human beings, a suitable antibiotic like ciprofloxacin is quite effective, particularly if used in the initial stages of the disease.

But in cattle, ciprofloxacin may be effective only in chronic cases.

Anthrax antiserum can also be used with good results.

In any case, antiserum should be given to all healthy animals to protect them from the disease.

Prevention and control:

The general measures for prevention of infectious diseases should be followed.

The healthy animals should be vaccinated.

Animals that have come in contact with diseased animals should be given anthrax antiserum to protect them from the disease.

2. Mastitis: It is the inflammation of udder that often occurs in dry cows due to infection of bacterium "cornybacterium pyogenes".

Viral Diseases

Animals suffer from a variety of viral diseases. For example, cattle suffer from rinderpest, foot and mouth disease, cowpox, etc. In this section, rinderpest is discussed in detail.

1. Rinderpest: This disease is caused by a virus and is highly contagious. The virus is present in all the fluids and secretions of the body of diseased animal. The disease spreads rapidly by direct contact with patient animals, through contaminated food, water, workers and their clothes and by flies.

Symptoms: Initially, the infected animal develops fever (40.0º to 42.2°C), loses appetite, develops constipation, and passes hard faeces that often are covered with blood. In the final stages of the disease, animal suffers from loose motions which gives off offensive odour. The body temperature declines and may go down below normal. The animal usually dies in about 7 days.

Treatment: Treatment is effective only when it is started in the initial stages of the disease. Injection of sulphamethazine sodium is often effective. Injection of rinderpest antiserum is highly effective, especially when combined with injection of sulphamethazine sodium.

Prevention: All the measures for prevention of infectious diseases should be implemented. It is highly desirable to vaccinate the animals against rinderpest. In 1954, a massive vaccination programme was initiated in India. This project has been highly successful, and rinderpest is no longer a dreaded disease.

Cattle of higher altitudes: Mithun is found in north-eastern India at an altitude of 700 to 1700 m. It is used for meat. Yak is found in Tibet, Ladakh, Lahaul, Spiti, Garhwal and Sikkim. Yak gives meat, hide and wool. It is also used for tilling land. The transport of people and goods across the desolate trans Himalayan region would be impossible without the yak.

2. Foot and mouth disease: If affects cattle, sheep, goats, pigs and other ruminants, caused by ssRNA Aphthovirus. It is characterised by eruption of vesicles over the lips, inside buccal cavity, over legs, feet, udder and even teats.

There is loss of appetite but dribbling of saliva is present. Lameness occurs.
The infected animals should be separated immediately and the animal house thoroughly disinfected.

3. Cow pox : It is mild self limiting eruptive skin disease of cows caused by cow pox virus. The infection is confined to udder and teats.

It spreads to humans accidently while milking infected animals.
Inoculum from cow pox lesions was used by Edward Jenner in 1798 as vaccine against small pox.

POULTRY

Poultry-farming deals with the rearing of fowls (chicken), ducks, turkeys, and pheasants for their eggs and meat. India and the neighbouring countries are recognised as the original home of the red jungle fowl (Gallus gallus). There is evidence that Aseel or Malay fowl were carried to Europe through the Middle East about 2,000 years ago and have given rise to the present-day European breeds.

1. Poultry and poultry products are a rich source of animal protein and other nutrients such as fats, vitamins and minerals. Consumption of eggs would pave the way for overcoming protein malnutrition prevalent especially among children in India.

2. Poultry-farming has definite advantages over livestock-rearing. Poultry birds are easy to raise, can be acclimatised to a wide range of climatic conditions, have short life span and are prolific breeders. Hens have an average yield of 60 eggs per year (upto 240 eggs in high-yielding varieties). Poultry-farming requires less space, is easier to manage and maintain and brings fast returns within a span of six months.

3. In a poultry farm, comfortable, well-ventilated and illuminated dry houses are built. Birds of different ages are kept in separate houses. In regions with moderate climate, they are kept in cages (coops). The floor is littered with chopped straw, paddy husk, dry leaves or ground nut hulls. It is made rat proof and provided with water channels with proper drainage. Minerals which are important for poultry diets are calcium, phosphorous, sodium, copper, iodine, iron, manganese and zinc. Vitamins required are vitamin A, 0 3' E, pyridoxine, riboflavin, pantothenic acid, niacin, folic acid, B12 and choline. The male breeder's diet should contain extra calcium, manganese and vitamin E to ensure proper fertility. Thus, a balanced diet is the requirement so that the utilization for building of tissues and egg production is maximised. Clean and fresh water is very essential for birds.

Light management: Light is essential for high egg production. 14 to 16 hours of light including daylight is required for optimum production. When the pullets (young hens especially at the time they begin to lay eggs) come into production, start giving additional light if the daylight is less than 12 hours. Gradually increase the light 20 minutes every week till 16 hours of total light is there. One tube light of 40 watt is sufficient for 36 sq.m area while 40 watt bulb is sufficient for 18 sq.m floor area. Light should spread uniformly. The light should not be provided for whole night.

4. Fowls are widely distributed as domestic animals and the most common species of jungle fowls are Gallus gallus, G. lafayetti and G. sonneratti.

5. Poultry feed includes all the nutrients and is made of cereals and millets, oil cake, protein concentrates, fish and meat meal, minerals and green vegetables.

6. The domestic fowl (Gallus domesticus) population of our country can be roughly classified into two types:

(i) Indigenous (desi type), (ii) Exotic (improved type)

Some of the indigenous breeds like Aseel , Karaknath, Ghagus, Brahma, Busra are the best table birds. The Aseel fowls are used in cock-fighting. The exotic breeds are classified, according to their source of origin, into American class, English class, Mediterranean class and Asiatic class. Some examples are White Leghorn, Rhode Island Red, Plymouth Rock and New Hampshire. They are now completely acclimatised to Indian conditions. Some of them are excellent egg-layers, whereas others give good meat.

Table : Breeds of Chickens

The indigenous breeds are crossed with exotic breeds for improving egg production. Heterosis has been utilised for producing better egg layers and broilers (birds grown for meat) with high nutritive value.

Some of the diseases like fowl pox, ranikhet, coryza, fowl cholera and aspergillosis take a heavy toll on poultry. But with better management, proper housing and nutrition and timely vaccination of the chicks, these diseases can be controlled.

7. Ducks comprise 6 per cent of the total poultry population in India. They are abundant in the southern and eastern parts of India. There are 20 breeds of duck of which Muscori, Pekin, Aylesbury and Campbell are popular exotic breeds; indigenous breeds include Indian Runner, Syhelt meta, etc. Brown and white geese are common in India. Turkeys which are in demand during Christmas time, belong to the breeds Narfold, British White, Broad Breasted Bronze and Beltsville Small White.

8. Poultry Diseases

(i) Encephalomalacia: Deficiency of vitamin E causes softening of brain tissue in young poultry.

(ii) Coccidiosis: The protozoan Eimeria causes coccidiosis in fowls. It causes bloody diarrhoea.

(iii) Bacterial Diseases

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Viral Diseases: Ranikhet, Fowl pox, Infectious bronchitis, Lymphoid leukosis.

Fungal Dieases: Thrush, Aflatoxicosis, Brooder pneumonia.

Ranikhet Disease is respiratory disease caused by Paramyxovirus characterised by coughing, sneezing and marked signs of respiratory diseases. Also known as 'New Castle disease'.

Marck's disease is primarilya disease of the young growing fowls caused by DNA virus. Paralysis is one of the major clinical symptoms.'

Bird Flu resembles influenza and is caused by a virus HN₁. The virus enters the man through chicken.

Coccidiosis caused by a group of protozoans called coccidia (e.g. Eimeria, Isopora) which affect the different parts of intestine.

Tick fever is transmitted through the fowl tick (Argus persicus). Usually tick bites the birds at night and parasite is transmitted into blood. High temperature, dullness, depression, greenish diarrhoea are its symptoms.

Perosis is due to deficiency of manganese in poultry birds. There is enlargement of tibiometatarsal joint twisting and bending of end of tibia.

Infectious Coryza is caused by Haemophilus gallinarum and infected birds show discharge from the nostrils and eyes.

Pullorum disease is caused by Salmonella pullorum. The heart, spleen, liver, kidney, lung and digestive tract are affected.

Aspergillosis is mainly disease of young chick and is caused by a fungus Aspergillus fumigatus. Normally the lungs are the major area of internal infection.

Mycosis is caused by a yeast called Candida albicans. It affects mostly upper portion of the digestive tract (mainly crop, proventriculus and gizzard).

APICULTURE

It is the care and management of honey bees. Honey bees give us honey and wax. They are good pollinators.

1. Common breeds of honey bee are

Apis dorsata (Rock bee)

Apis indica (Indian bee)

Apis florea (Little bee)

Apis mellifera (Italian bee)

2. Honey produced by the honey bee Apis species is probably the oldest sweetening agent in our civilisation. Honey contains two sugars -dextrose and levulose -and a mixture of several other substances. It is tasty, health-giving and also medicinally useful. Honey bees also yield wax, which has multiple uses. A large quantity of honey is still collected from wild sources. However, bee-keeping (apiculture) using domesticated bees has been practised in many parts of the world, including India (using A. dorsata, A. florea and A. indica).

3. Social organization (Castes) of honey bee: The nest of honey bee is known as the bee-hive. The hive consists of 32 to 60 thousand individuals, showing a highly organized division of labour in the colony. Bees are polymorphic, consisting of three types of individuals (Castes) viz, QUEEN, DRONE and WORKER. The characters are given in the following table.

4. From its mandibular gland, the developing queen secretes antiqueen substances or antiqueen pheromones which inhibit the worker bees from building brood chambers and developing ovaries.

5. Drones are male honey bees. They develop from unfertilized eggs. The phenomenon is called arrhenotoky. Drones and virgin queens take part in nuptial flight. After copulation, the drones are not allowed to come back into hive.

6. The queen stores the sperm in her spermatheca. They are sufficient to fertilize all the eggs that are laid by her.

7. Females develop from fertilized eggs. Workers are sterile females. Scout bees search for food and intimate the same, to worker bees by dances -round dance for less than 75 m and tail wagging dance for longer distances (Frisch) of the new food source from the hire.

8. Workers have a pollen collecting apparatus in hind legs called corbicula and nectar storing mechanism in crop and wax secreting glands in abdomen.

9. Young workers secrete royal jelly and are called nurse bees. Royal jelly is given to queen or potential queens. Apiculture is the rearing of bees or bee keeping for collecting of honey and wax.

10. Honey is near neutral sugary syrup with 6.8 pH, having 17-25% water, 3.3% minerals, abundant vitamins (B₁, B₆, C, D), L-fructose (Laevulose, 41%), glucose (35%), sucrose (1.9%) and dextrin (1.5%). It is tonic, laxative and sweetening agent. Bee wax is secreted by abdominal wax glands of the worker bees. It possesses a hardening substance from cephalic gland and a resin called propolis from pollen grains.

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Importance of Honey bees: Honey bees have the following importance.

1. Honey: The honey is a natural valuable tonic for human body. It contains various substances of high medicinal value, including important enzymes, vitamins and sugars, mainly glucose and fructose. It prevents infection if applied to a wound. A number of ayurvedic medicines are taken with honey.

2. Bee wax : Bee wax is made of secretion of worker bees' abdominal glands. It is a product of industrial importance. It is used in the manufacture of many items including cosmetics, shaving cream, face cream, ointments, plasters, carbon papers, pencils, electric goods, toothpaste, lotions, furniture-polishes, boot-polishes, protective coating, ink paints and candles. It is also used in model and mould making and in printing industry. It is also used in the laboratory for microtomy with the common wax for block preparation of the tissues.

3. Pollination: The honey bees are pollinators of many crop species such a sunflower, Brassica, apple and pear.

4. Medicinal value: A drug, prepared from the bodies of honey bees, is used in the treatment of Diphtheria and some other dangerous diseases. The venom of honey bees has been used in the treatment of arthritis and snake bite.

The detailed studies on the habits and behaviour of the honey bee led to the development of apiculture not only as a useful hobby but a large scale profitable trade to produce honey and wax in large quantities.

The honey-bees are reared in wooden boxes having a large brood chamber placed on a wooden platform with an opening for the entry and the exit to the bees at the bottom.

A number of frames coated with wax sheets having hexagonal imprints are placed in the chamber vertically with the help of wires.

The bees start making cells along the margins of hexagonal imprints.

Each wax sheet, known as comb foundation, provides the foundation arc for the bees to build combs on both the sides.

Another frame fitted with wire meshing for the easy passage of the workers is placed over the vertically placed frames.

A chamber called super having additional similar frames for more comb foundations meant for the expansion of the hive, is placed over the brood chamber.

The wire meshing referred to above, extends between the brood chamber and super.

In order to provide ventilation, light and protection, a cover having holes is placed over the super.

To start a colony in the artificial hive, a gravid (fertilized) queen is inducted into the brood chamber.

Artificial hives are placed in gardens, orchards and fields having flowering plants to provide the pollen and nectar.

When sufficient honey has been stored, the combs are removed from the frames and then centrifuged to extract the honey.

The same comb can be used again.

The appliance used for the extraction of honey are a pair of gloves, a knife, a brush to remove the bees from taken out combs and a centrifuge.

Bee Enemies: These include the wax moths (e.g., Galleria mellonella), wasp (e.g., Vespa) , black ants (e.g., Componotus compressue) and bee eaters (e.g., Merops orientalis and king crow, Dicrurus macrocerus). Man is the last but worst enemy of honey bees.

Bee Diseases : Honey bees suffer from Nosema disease caused by a sporozoan Nosema apis, paralysis dysentery and acarine disease caused by a parasitic mite, Acarapis woodi.

FISHERY

A large section of the Indian population uses fish as food. Fish is an easily available source of protein. It is highly nutritious and easily digestible. In India, edible fishes are abundantly available from sea, rivers, lakes, ponds and marshes. Fish is also an item of export trade.

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"Aquaculture" involves production of useful aquatic plants and animals such as fishes, prawns, shrimps, lobsters, crabs, molluscs (edible and pearl oysters) by the proper utilisation of small and large bodies of water. "Pisciculture" is the production of fishes.

Fishes are reared in small rivers, lakes and canals.

Fish eggs are introduced into nurseries (hatcheries).

The young ones hatched from the eggs are fed, tended and nursed and harvested when full grown.

Aquaculture techniques of induced breeding by the administration of pituitary hormones have helped in the production of seed fish in pure form.

Hatcheries with Circulating water have ensured almost 100 percent hatching of fertilised eggs.

Culturing fish in fresh water is known as 'Inland fisheries'.

Fish industry also includes trapping and capturing fishes from estuaries, sea coast and even from within the sea by using sophisticated electronic locaters, baits, nets and trawlers.

A large number of fishermen living in the coastal regions of India still use catamarans and various traditionally built boats.

Mechanised fishing boats have now made deep-sea fishing possible.

Catching, processing and packaging of marine fishes have been developed on a scientific footing in our country.

India exports marine food to several countries.

Besides serving as table food, fishes are of medicinal value.

Shark liver oil and cod liver oil are natural sources of vitamins A, C and D.

Oil from sardines, herrings and salmon is used in the manufacture of soaps and paints.

Concept Builder

Fish meal is a rich source of protein for cattle and poultry. It is prepared from the nonedible parts of fishes such as tails, fins and bones which are discarded from factories that extract oil from fishes. Fish waste is also used for making fertilisers and adhesives. Shark leather (shark skin) called shagreen is used to make articles such as hand bags, shoes and tobacco pouches and is considered fashionable and fetches a high price in the market.

Pisciculture is rearing, catching and management of fishes.

Culture fishery is the raising of fishes in tanks and ponds while capture fishery is management of catching of fish without actually raising them.

India has 1.6 million hectares of inland water (annual yield 2.242 million tonnes, 1996 data) and over 2.59 km² of continental shelf for fishing (annual yield 2.7 million tonnes, 1996 data).

Table : Important Edible Fishes of India

Culture Fishery: In this method, pituitary hormone extract is injected into male and female breeder fish.

Two males and one female are then kept in a breeding happa, a bamboo and cloth container.

Spawning takes place in 3-6 hours.

The fertilized eggs are removed and kept in hatchery, where they hatch in 15-18 hours.

The hatchlings are kept in glass-jar hatcheries.

A mouth is formed on the third day and the young fish are now called fry.

They are kept in rearing ponds for about three months, where they grow into 4"-6" long fingerlings.

The fingerlings are then released into stocking ponds where they grow to the required size.

In composite fish culture, different species of fish like catla, rohu and mrigal are cultured together.

Types of Ponds: Three types of ponds are required for the culture of Indian major carps: nursery, rearing and stocking ponds.

(i) Nursery Ponds: Efficient pond fish culture requires special preparation of nurseries to receive the tender hatchlings at spawn. Small and seasonal nurseries are preferred as they facilitate effective control of the environmental conditions. The steps adopted towards preparation of nurseries are control of predatory fishes and weeds, There should be production of zooplankton to serve as food for spawn and control of algal blooms.

(ii) Rearing Ponds: The fries (sing. fry = young one of fish) are collected from the nursery ponds and released in rearing ponds where fries develop into fingerlings.

(iii) Stocking Ponds: The fingerlings are netted out from the rearing ponds to stocking ponds where they change to fish. In the stocking ponds, the fishes are kept for stocking.

Marine fisheries: The marine fishery is divided into coastal fisheries (about 3 miles from the coast line), and deep sea fisheries, which have different fauna of fish. In India, about 75% of the marine fish catch is from the western coast.

The main marine fisheries are Sardines (26%), Mackerel (9.7%) and the Bombay duck (11%).

Crustacean fisheries i.e. Prawns, Lobsters, Crabs, Penaeus sp. are dominant on the west coast. Mollusc fisheries include oysters, clams, mussels, squids, cuttlefish and octopus.

Estuarine fisheries : The place where the fresh water of rivers meets the salt water of the sea is called an estuary. It contains brackish water.

At estuary only those fishes of fresh water and sea can survive that can tolerate a change of salinity.

The estuary also forms the nursery ground for several marine and fresh water species.

Fishing on large scale from such places, results in the death of number of young and immature fishes.

Bag nets are most commonly used in estuarine fishery.

The major estuarine systems in India are (1) Hooghly -in West Bengal. (2) Mahanadi estuary in Orissa. (3) Cauvery estuary in Tamil Nadu. (4) Narmada and Tapti estuary in Gujarat and (5) Godavari-Krishna estuary in Andhra Pradesh.

Carp fishes such as catla (theila), Labeo rohita (rohu), Cirrhinus mrigala (mrigal) and Labeo calbasu (kalbasu) are commonly cultured together in our country.

Such a practice of culturing together of fishes is called polyculture or composite culture.

Important edible fishes are :

A. Fresh water fishes: Rohu (Labeo rohita), Calbasu (Labeo calbasu), Catla (Catla catla), Singhara (Mystus singhala), Magur (Clarias batrachus), Singhi (Heteropneustes)

B. Marine fishes : Bombay duck (Harpodon sp.), Hilsa (Hilsa sp.), Eel (Anguilla sp.), Pomphret (Stromatetis sp.), Salmon (Aluitheronema sp.), Sardine (Sardinella sp.)