However, the inbreeding may result in homozygous recessive genes coming together to express some harmful phenotypic traits. Many breeding scientists have observed that hybrid vigour and fertility were lost due to repeated inbreeding. Such recessive and harmful genes are removed by some special techniques without sacrificing the major quality of the animal. If the race is relatively free of such harmful recessive genes, the process of inbreeding is a safe method for improvement of animals.
Out breeding in animals is useful for different purposes viz.,
Beef cattle may be crossed with dairy cattle to produce calves for superior veal (flesh) production.
Representative examples of improvements in animals by mutations include poultry that is resistant to white diarrhoea, increased egg production in fowls, increased fat content in milk and better meat yielding in Turkeys etc.
The animal breeder faces many complex problems during hybridisation experiments because many traits of animals are dependent on the interaction of multiple genes. When the attempts are made only to increase the size of eggs in fowls,it was observed that the progeny produced yielded few number of eggs or even they die sometimes. That is if only one character is taken for improvement of the animals, the other characters will degenerate or result in harmful effects. Hence at the time of selection all the desirable characters are to be taken into consideration. The techniques for the improvement of animals involve principles of selection based on quantitative variations. It is not possible for all of the desirable traits to be obtained in one individual. The successful product must contain maximum number of desirable traits and a minimum number of undesirable traits.
In milk yielding cattle and egg yielding fowls if most of their food material is converted into productivity, such cattle and fowls are considered as more valuable. The above mentioned are only few of the desirable qualities that the animal breeders select for improvement of animals.
- Bacterial diseases
- Viral diseases
- Fungal diseases
- Protozoan diseases
- Parasitic diseases
- Nutritional deficiency diseases
- This is the egg transmitted disease.
- The production of the eggs falls down in layers.
- The symptoms of the disease are sneezing, swollen sinuses, eyes and respiratory distress, reduced body weight, etc.
- Disease could be controlled by dipping of hatching eggs in antibiotic solutions and giving antibiotics such as Tylosin.
- This disease is spread by the birds like crows.
- The symptoms of the disease are
(a) Greenish yellow diarrhea
(b) Purplish discoloration of comb and wattles, and
(c) Respiratory trouble, stop feeding.
- Disease could be controlled by treating with sulphonamides and antibiotics.
- The disease is transmitted through water and moist litter.
- Symptoms of the disease are coughing, sneezing, swoollen face, breathing problem, eye lids stick together and the discharge from the eyes and nostrils emit bad smell, reduced feed consumption and low egg production.
- Disease may be controlled by treating the birds with sulphathiazole in water and feed or giving streptomycin intramuscularly.
- This disease is caused by Salmonella pullorum to young chicken of 5-10 days.
- The fowls themselves are the carriers of this disease.
- The body of young chicken is moist and aggregate in groups.
- Symptoms of the disease are . dullness, and white diarrhoea. Due to this symptom, this disease is called Bacillary white diarrhoea. Breathing problem and high mortality occur in these birds.
- Nitroferan compounds are used to control mortality.
- This disease is caused by spirochaets.
- The disease is transmitted by the fowl ticks, hence it can be called tick fever.
- Symptoms of the disease are high fever, greenish diarrhoea, pale combs and wattles, increased thirst and paralysis before death.
- The disease may be controlled by killling ticks and giving pencillin for the birds.
- This is contagious disease.
- The wings and fleck fall down. They do not drink water. Weight of the body reduces. They move away from other fowls.
- Symptoms are paralysis and loss of vision in old birds.
- No treatment is available but vaccination to the young chicks gives protection.
- This is also called New castle disease.
- It is a contagious disease.
- Symptoms are breathing problem, coughing, nasal discharge, greenish diarrhoea and paralysis.
- No specific treatment is available. However, mild doses of vaccine followed by booster doses of strong vaccine reduce the risk of disease.
- This is a contagious disease.
- Symptoms are sneezing, coughing, high mortality in young ones, drop in egg production, thin shell eggs, etc.
- No specific treatment, but mass vaccination of young chicks is effective in preventing the disease.
- This is a contagious disease which affects the older birds.
- The symptoms are:
(a) Marked respiratory problems, swelling of the face
(b) Drop in egg production and
(c) High mortality rate.
- No definite treatment but vaccination controls the disease to some extent.
- This is a mild disease effecting young chicken and layers.
- The main symptom to identify this disease is the typical wart -like structure, skin or mouth found on the comb.
- Breathing is difficult. It spreads through mosquitoes.
- Vaccination is proved to be effective.
- It is infectious and effects younger birds of 4-8 weeks.
- Disease spreads through feed and water.
- Symptoms of the disease are watery diarrhoea, depression stop feeding and young ones shiver.
- This disease is also named as Aspergillosis. It is caused by a fungus, Aspergillus fumigatus. This disease spreads through litter and feed to the young ones of brooding stage.
- Symptoms of the disease are breathing problem, gasping, inflammed eyes and high mortality.
- No treatment is available.
- This disease is caused by Asperigillus flavus.
- It spreads through contaminated litter and feed.
- The symptoms are variable. Fall of immunity and are liable to be afected with other diseases. The egg laying capacity falls down and the fowls are destroyed.
- It may be prevented by avoiding moisture, contaminated teed and litter.
- The protozoan parasite, Elmeria causes coccidiasis in fowls.
- It spreads mostly to young ones through litter and water.
- The symptoms are: depression, droopiness, ruffled feathers, young ones agregate in flocks, take less food and water, and bloody diarrhoea. Mortality in these birds is severe.
- This can be treated through water medication. Nitrofurazone and other medicines are often used.
- Ectoparasites Ticks, mites, lice and fleas are the common ectoparasites. They cause generally severe irritation by biting or sucking.
They can be prevented by using insecticide like DDT.
- Endo parasites Helminths like nematodes (round worms) cestodes (tape worms) and trematodes (flukes) are the common endo parasites. The symptoms caused by these organisms vary depending on the parasite. For treatment, the drugs like carbontetrachloride, turpentine are used.
- The poultry houses or farms are to be located in non-residential areas so that the poultry is away from noise, dust, etc.
- The farm should be constructed in such a way that it maintains good environmental conditions.
- The farm should be elevated from the ground. Due to this, water may not get into the farm during rainy season.
- The poultry farms are to be constructed in east to west direction along their length. As a result, good sun-shine is available.
- The farm is to be located in a place where transport facilities are available. Water, electricity, feed and equipment are to be within the reach of the farm.
- The farm is to be located near the consumer areas.
- The poultry housing also requires proper temperature and light. At 30° C, the chicken can lay eggs well. Electric bulbs should be arranged at a height of 7ff. in poultry farms to provide warmness. These lights are to be switched on during first seven weeks. A relative humidity of 50-60% is ideal for poultry.
- The sheds are to be ventilated properly. Proper ventilation helps in providing sufficient oxygen for birds and removes harmful gases such as ammonia and carbon dioxide. It also removes moisture in the house and helps in keeping optimum temperatures. To facilitate ventilation, the farm house is to be constructed in such a way that it should have an open front, adjustable windows or cloth covered frames and ventilation at ridge level.
- The flooring of poultry house is to be constructed either with cement or napa slabs. Its roof is to be constructed either with palmyra leaves or cement sheets.
- The chicken in a poultry farm are to be fed with sufficient food and water. Food troughs and water troughs are to be arranged depending on the size of poultry farm. The egg laying pots are also to be established in poultry sheds. One food trough is to be kept for every 20 fowls. The food troughs should not be filled completely with food material. The water given to fowls should be always clean and sufficient.
- Deep Litter System
- Cage System
- In this method, there is no wastage of space and food.
- Chicks involved in cannibalism may be easily identified and removed. Cannibalism in poultry is referred to as one bird pecking at the other bird.
- The diseased birds can easily be separated.
- Less labor is involved in this method.
- Collection of eggs is an easy process.
- Mortality rate is less in this system.
- The cracked eggs are common.
- It is difficult to clean the individual cages and to dispose the manure.
- The food may not be distributed accurately depending on the consumption of the birds in the cage.
- The birds are frequently subjected to a disease called cage layer fatigue. The bird lies on its side giving an impression that it is affected with paralysis. Hence, this is referred to as cage paralysis or cage layer fatigue.
- Fatty liver syndrome is common in cage system. It is characterised by
(a) a gradual drop in egg production (40% - 10%),
(b) fatty, enlarged, tan colored liver is noticeable, and
(c) birds become fatty.
- In summer, water is to be sprinkled on cages. This is due to the fact that cage poultry needs protection from excessive heat in severe summer.
- The chicks should be subjected to dubbing and debeaking. As a result of debeaking, the chicken may not involve in cannibalism and can easily procure the soft food without waste.
Water is to be supplied 3 to 4 times a day. The temperature maintained in the brooders is to be decreased gradually per every week. As a result, only 75° - 80°F temperature persists in brooders. From 9th week onwards, the lights may be reduced in the poultry. For a few days, zero watt bulbs are used to maintain light. The young chicken are subjected to debeaking on 21st day.
The chicks grown for about twenty weeks are called growers. The growers are to be fed with grower mash or grower ration.
After one month the male and female are to be separated and reared separately.
The food given to broilers up to 42 days is called broiler starter mash. It contains 25% of proteins. From 7th week onwards, each broiler weighs 1 - 1.5 kgs. and get ready for marketing purpose. The food given to broilers from 7th week onwards is called broiler finish mash. It contains more carbohydrates and less proteins. In broilers the wieght of male or cock is higher than female or hen.
- Poultry requires less investment.
- It generates income in a short span of time.
- It provides work round the year.
- It can be started as a cottage industry.
- It produces good quality of animal proteins. (Nutrient value of egg is 13.3% of proteins; 13.3% of fats; 173 K. cal. of energy; 60 mg. of calcium; 220 mg. of phosphorus and some vitamins, iron efë. About 100 gms. of flesh of chicken consists of 26.0% proteins; 0.6% fats; 109 K. cal. of energy; 25mg. calcium and 245 mg. phosphorus).
- It can be started as a self employment scheme.
- The feed can be better utilised by poultry. As a result, less food consumption and better growth of poultry are realised.
- Poultry is also suitable for mixed farm conditions.
- Marketing facilities for the sale of poultry products are available.
- May be hereditary
- Rearing of number of fowls in less space
- Since they are not subjected to debeaking
- Supplying more tasteful, energetic and salty food and
- More temperature in the poultry farm.
- As food
- They give by-products
- To control diseases
- Fin fish fishery
- Shell fish fishery.