Effects of Heat Stress on the Well-Being, Fertility, and Hatchability of Chickens in the Northern Guinea Savannah Zone of Nigeria: A Review

Abstract

The paper examines heat stress and its adverse effects as a hindrance to profitable poultry production in the tropics, with emphasis on the Northern Guinea Savannah zone of Nigeria. It elucidates the general negative effects of heat stress on physiological parameters of domestic chickens, and the specific impact of the stress on reproduction in the tropics. The deleterious effects are expressed in poor poultry well-being and reproductive performance. It is concluded that measures aimed at alleviating heat stress in domestic chickens must be adopted in order to enhance reproductive and, consequently, efficiency of modern poultry production in the tropics.

Physiological Responses of Slow-Growing Chickens under Diurnally Cycling Temperature in a Hot Environment

“…The high HR in the first week may have resulted from the high relative humidity. Literature reports show that direct meteorological factors affecting chickens include elevated T a and high RH, resulting in heat stress which leads to elevated HR (Ayo et al, 2011). The subsequent HR decreases observed in this study could also be a consequence of habituation due to repeated exposure to similar environmental conditions as well as to handling.…”

“…It is vital to understand the effects of high temperatures on free-range chicken performance, in view of the anticipated increase in global average surface temperature by between 1.88°C and 4.08°C in the next 60 years (Renaudeau et al, 2011). High T a and RH are some of the direct meteorological factors affecting birds, and may cause severe heat stress (Ayo et al, 2011).…”

Effects of strain and sex on the behaviour of free-range slow-growing chickens raised in a hot environment

“…High humidity impacts thermoregulation and welfare of chickens (Lin et al 2005), in that humid conditions reduce the effectiveness of heat dissipation (Warriss et al 2005). This impairs normal body functions as efficiency is achieved if body temperature is kept constant or maintained within a narrow range (Ayo et al 2011). The normal body temperature of an adult chicken is 40.6-41.7°C, while the thermo-neutral zone (TNZ) is 18-24°C (Fanatico et al 2007).…”

“…Factors such as temperature (Kristensen et al 2007) and humidity influence life cycles, reproductive ability, growth rates and thus body weights (BWs) of birds. Direct meteorologic factors affecting birds include, especially, high ambient temperature and relative humidity, and may result in severe heat stress (Ayo et al 2011). High humidity impacts thermoregulation and welfare of chickens (Lin et al 2005), in that humid conditions reduce the effectiveness of heat dissipation (Warriss et al 2005).…”

“…Meteorologic elements constitute a major variable for outdoor operations (Sossidou et al 2011), and the concern and emphasis for such elements in recent years are due to the fact that they are not constant, but change continuously (Ayo et al 2011). Factors such as temperature (Kristensen et al 2007) and humidity influence life cycles, reproductive ability, growth rates and thus body weights (BWs) of birds.…”