Tiêu đề Animal Husbandry Part-11.pdf ✅

www.iaritoppers.in Whatsapp : +91-9694095242 Page | 1 Animal Husbandry 5 th Edition 2024
www.iaritoppers.in Whatsapp : +91-9694095242 Page | 2 Incubation and Hatching: Principles of Incubation: Five major functions are involved in the incubation and hatching of poultry eggs. They are: 1) Temperature 2) Humidity 3) Ventilation (Oxygen and Carbon dioxide level and air velocity) 4) Position of eggs 5) Turning of eggs 1. Temperature:  Embryo starts developing when the temperature exceeds the Physiological Zero.  Physiological zero is the temperature below which embryonic growth is arrested and above which it is reinitiated.  The physiological zero for chicken eggs is about 75°F (24°C).  The optimum temperature for chicken egg in the setter (for first 18 days) ranges from 99.50 to 99.75°F and in the hatcher (last 3 days) is 98.50°F. 2. Humidity:  Humidity for the first 18 days - 55 and 60% (in setter)  For the last 3 days ranging between - 65 and 75%.  Higher humidity during hatching period is given to avoid dehydration of chicks. 3. Ventilation:  Generally the oxygen content of the air in the setter remains at about 21%.  For every 1% drop in oxygen there is 5% reduction in hatchability.  The tolerance level of CO2 for the first 4 days in the setter is 0.3%.  CO2 levels above 0.5% in the setter reduce hatchability and completely lethal at 5.0%. 4. Position of eggs:  Artificially incubating eggs should be held with their large ends up.  Under normal circumstances eggs are set with large end up for the first 18 days (in setter) and in horizontal position for the last 3 days (in hatcher). 5. Turning of eggs:  eggs to be turned at least 8 times a day.  In large commercial incubators the eggs are turned automatically each hour i.e. 24 times a day.
www.iaritoppers.in Whatsapp : +91-9694095242 Page | 3  Most eggs are turned to a position of 45o from vertical, and then reversed in the opposite direction to 45° from vertical.  Rotation less than 45o are not adequate to achieve high hatchability.  Turning is not required in Hatcher. Factors Setter Hatcher Temperature 99.50 to 99.75°F 98.5°F Relative Humidity 55-60 % 65-70 % Position Large end up Horizontal Turning Manual - 8 times Automatic - 24 times No turning Brooding of Chicks:  Brooding is the art and science of rearing baby chicks. A newly hatched chick does not develop the thermoregulatory mechanism fully and takes about two weeks to develop this mechanism and homeostasis. Therefore, they cannot maintain the body temperature properly for the first few weeks of life; and may be subjected to chilling, if not properly taking care of. Natural brooding:  It is done with the help of broody hens after hatching, up to 3 to 4 weeks of age. Artificial brooding:  In artificial brooding large number of baby chicks are reared in the absence of broody hen.  Equipments used for brooding are called brooders. Brooder comprises of three elements: 1. Heating source 2. Reflectors 3. Brooder guard Heating source may be electrical, gases like natural gas, LPG and methane, liquid fuel like kerosene, solid fuel like coal, wood can be used as a heating material. 1. Charcoal stove / kerosene stove 2. Gas brooder 3. Electrical brooder:
www.iaritoppers.in Whatsapp : +91-9694095242 Page | 4  One electrical brooder can be used for 300 to 400 chicks. 4. Infra-red bulbs:  It is a self reflecting bulb. One 250 watts IR bulb can provide brooding for about 150 to 250 chicks. 5. Reflectors: Fig: Light reflector These reflectors are called Hovers. 6. Brooder guard / chick guard  Brooder Diameter – 5 feet  Brooder Height – 1.5 feet  Materials like cardboard sheet, GI sheet, wire mesh, and mat etc. can be used depending upon the season of brooding.  During summer season, brooding is done for 5-6 days. In winter season it is 2-3 weeks.