Climate Change Impact on Immune …
491
Breast Blisters and Crooked Sternum
This phenomenon occurs in heavy-weight birds which brooding in wire cages or on
the floor. As age and weight increase, birds sit on the wired floor or mattress. During
this period, this weight is placed on the bone sheath. There are blisters and breast
ulcers, especially during high temperature, the birds search for the wet places inside
the house. Also, the increase of humidity mattresses with poor specifications, high
content of microbes and pathogens. This leads to the occurrence of breast defects and
lower the carcass quality during the stages of slaughtering, then reduce economic
return. The breeders can reduce the incidence of this phenomenon by work for a
program to market heavy birds first to early ages, ensure the cleanliness and quality
of the mattress and finally avoid the presence of dark areas in the house so as not to
be left to birds.
4 Feeding Strategies to Deal with Heat Stress
4.1 Feed Restriction
Starving the birds during peak heat stress is an effective way to reduce body temperature and increase survival, as feed intake increases heat increment resulting from
ingestion, digestion, absorption and metabolism of nutrients. Feed restriction, in the
meantime, makes birds quiet and less energy-producers. Metabolic heat increment
is a maximum after 3–6 h of feed intake. Therefore, it is necessary to feed the birds
early in the morning and late in the afternoon so that the production of metabolic
heat will not occur during higher temperature period of the day (09:00 to 16:00 h).
By this way birds will be encouraged to eat during cooler periods of the day and help
maintain their performance during hot weather.
4.2 Feed Pelleting
The amount of feed intake by chickens is reduced at hot weather [13] and as a
result, the amount of feed components consumed decreases. This is one of the main
reasons leading to lower productivity of birds and their performance with the high
feed conversion ratio to non-economic degree. Therefore, there are many attempts
to increase the quantity and/or the concentration of feed ingredients consumed,
without increasing internal body heat, in order to improve birds’ performance and
productivity.
Pelleting process increases the physical density of feeds; the pelleted diet also
improves the digestibility, decreasing the production of metabolic heat with respect
491
Breast Blisters and Crooked Sternum
This phenomenon occurs in heavy-weight birds which brooding in wire cages or on
the floor. As age and weight increase, birds sit on the wired floor or mattress. During
this period, this weight is placed on the bone sheath. There are blisters and breast
ulcers, especially during high temperature, the birds search for the wet places inside
the house. Also, the increase of humidity mattresses with poor specifications, high
content of microbes and pathogens. This leads to the occurrence of breast defects and
lower the carcass quality during the stages of slaughtering, then reduce economic
return. The breeders can reduce the incidence of this phenomenon by work for a
program to market heavy birds first to early ages, ensure the cleanliness and quality
of the mattress and finally avoid the presence of dark areas in the house so as not to
be left to birds.
4 Feeding Strategies to Deal with Heat Stress
4.1 Feed Restriction
Starving the birds during peak heat stress is an effective way to reduce body temperature and increase survival, as feed intake increases heat increment resulting from
ingestion, digestion, absorption and metabolism of nutrients. Feed restriction, in the
meantime, makes birds quiet and less energy-producers. Metabolic heat increment
is a maximum after 3–6 h of feed intake. Therefore, it is necessary to feed the birds
early in the morning and late in the afternoon so that the production of metabolic
heat will not occur during higher temperature period of the day (09:00 to 16:00 h).
By this way birds will be encouraged to eat during cooler periods of the day and help
maintain their performance during hot weather.
4.2 Feed Pelleting
The amount of feed intake by chickens is reduced at hot weather [13] and as a
result, the amount of feed components consumed decreases. This is one of the main
reasons leading to lower productivity of birds and their performance with the high
feed conversion ratio to non-economic degree. Therefore, there are many attempts
to increase the quantity and/or the concentration of feed ingredients consumed,
without increasing internal body heat, in order to improve birds’ performance and
productivity.
Pelleting process increases the physical density of feeds; the pelleted diet also
improves the digestibility, decreasing the production of metabolic heat with respect