title: Metabolic and biochemical changes during heat stress in relation to the feathering degree of the domestic hen.
abstract: Rhode Island Red layers, consisting of four genetically different feathering types- fully feathered (nanaff), fully frizzled feathered (nanaFf), naked neck (Nanaff), naked neck frizzled type (NanaFf)- were exposed to heat stress, and the physiological and metabolic responses were evaluated according to the feathering degree. Heat stress conditions (34 degrees C and relative humidity of 45%) were maintained for 8 weeks. Body temperature measured at different points, body characteristics and blood gas and electrolytes were determined and related to the environmental heat conditions. A plumage reduction led to higher body surface temperature, improved heat loss and, consequently, lower body-core temperatures. This was accompanied by a reduced polypnoea as reflected by higher blood levels of CO2, and smaller increases in blood pH and alkalosis with better stabilization of acid-base balance and electrolytes homeostasis. Reduced plumage seems to contribute to a greater resistance to hyperthermia caused by high ambient temperatures.
authors.affiliation: Institute for Animal Production, Technical University, Berlin, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Pech-Waffenschmidt
authors.forename: E
authors.initials: E
authors.lastname: Bogin
authors.forename: Y
authors.initials: Y
authors.lastname: Avidar
authors.forename: P
authors.initials: P
authors.lastname: Horst