EFFECT OF PHOTOPERIOD,LIGHT DARK REGIMS ,RESPONSE IN

EFFECT OF PHOTOPERIOD,LIGHT DARK REGIMS ,RESPONSE IN POULTRY PRODUCTS BY Ameelal Jakhar 2010AS240M: 

EFFECT OF PHOTOPERIOD,LIGHT DARK REGIMS ,RESPONSE IN POULTRY PRODUCTS BY Ameelal Jakhar 2010AS240M

Introduction: 

Introduction In the Mediterranean region poultry are raised in a climate in which the summer temperatures are rather high and the winter temperatures are more or less severe. The type of final product desired is greatly influenced by the eating habits and the age-old traditions of this region.

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Both the environment and breeders have interacted in the selection of animals over time so as to obtain strains that are adapted to particular conditions.

Effects of light: 

Effects of light 1. Photoperiod:- Light is of fundamental importance in the reproduction of birds, both during the rearing and the laying time . Two different situations can be identified :- a) in which closed sheds and artificial light are used, and b) in which the sheds have windows, and natural light is available.

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During the rearing period (0-18 weeks), the most convenient light programme can be used in situation A :- a constant 8 hours of light and 16 hours of dark (8L:16D) for the entire period. . In situation B, there are two phenomena:-

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1"- Chicks born more or less between April 1 and September 15, are in the best situation (in the northern hemisphere) since they have a decreasing photoperiod and it is not necessary to modify the number of hours of natural light ; 2"- Chicks born between September 16 and March 31 are worse-off because the natural photoperiod is increasing and this can lead to premature laying.

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According to Shanawany ( 1983 ), the best age for the hen to reach sexual maturity is 150-160 days, and this is the condition for producing the largest number of eggs with the best alimentary conversion index(ACI). When the number of hours of light is increased from 8L:16D to 14L:lOD by the 15th to 18th weeks of life instead of the 21st, there is an increase in the number of eggs produced, but they weigh less ( Leeson and Summers , 1980).

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Therefore, it is generally advised to start a progressive increase in light during the 18th week of life, with the daily increases suitable for stimulating sexual maturity and with it the initiation of oviposition at the best time. The hens begin to lay about 4 weeks after the start of photostimulation.

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A photoperiod of 10L:14D is sufficient for stimulating oviposition and 14L:lOD provides the maximal production. Further increases to 17L:7D do not consistently increase production and if the exposure to light is even greater than this, production decreases. Rowland (1982) compared 18L:6D with 15L:9D and found a larger percentage of breakage of the shell in the oviduct, 6.4 vs 2.4 YO, and a worsening of the specific gravity of the shell with the longer light exposure

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Quality of the light:- Except for the first week, in which intense light is needed to stimulate the chicks to eat, the intensity of the light should be lower than natural light . Different studies with the hen ( Cavalchini et al., 1976 ; Morris,1968 ) found that for good reproductive activity there should be at least 10 lux of light .

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There is a strict linear correlation between the intensity of light and body activity. As one increase light from 1 to 120 lux, the motor activity of the animals increases. Several studies of the influence of the colour of light have shown that birds are more sensitive to wavelengths toward orange and red and less sensitive to blue, green or yellow.

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The optimal wave-lengths are between 600 and 750 nm. In studies that if monochromatic light is used, sexual maturity is shifted from day 131 to day 124 of life.

Manipulations of the photoperiod and ahemeral cycles: 

Manipulations of the photoperiod and ahemeral cycles In the last few decades most of the research into the effects of light has been carried out to determine the possibility of using intermittent light programmes or circadian cycles longer or shorter than 24 hours, called ahemeral cycles.

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Lighting programs improve livability by decreasing mortality as spelled out in the following partial list of causes:-- a) Reduction in mortality due to ascites (water-belly) and sudden death (flip overs). b) Reduction in mortality due to leg disorders such as valgus/varus, spondylolisthesis (kinky back) and rotated tibia

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c) Reduction in spiking mortality d) Improved immunocompetence

Lighting Programs for Commercial Layers : 

Lighting Programs for Commercial Layers

Lighting Programs for Breeders (broiler and commercial layers) : 

Lighting Programs for Breeders (broiler and commercial layers)

Lighting Programs for Broilers/Roasters: 

Lighting Programs for Broilers/Roasters