Thermoneutral zone and resting metabolic rate of broilers

Area of Science:

• Animal Science
• Poultry Science
• Environmental Physiology

Background:

• Broiler production is a significant global industry.
• Optimizing environmental conditions is crucial for broiler health, performance, and economic efficiency.
• Understanding metabolic rate and thermal comfort thresholds is key to effective environmental management.

Purpose of the Study:

• To develop mathematical models describing the metabolic rate of broilers.
• To establish equations for the lower critical temperature (Tcl) in relation to age and body weight.
• To provide data for optimizing environmental control to enhance broiler performance and reduce production costs.

Main Methods:

• Metabolic rate (oxygen consumption) was measured weekly in broilers from 1 to 63 days of age.
• Regression analyses were performed to derive equations for metabolic rate and Tcl based on body weight and age.
• Data were collected for both male and female broilers across different weight and age ranges.

Main Results:

• Specific equations were determined for minimal resting metabolic rate as a function of body weight, differing between sexes and weight categories.
• Equations were established for Tcl in relation to age for young chicks and older birds, as well as a single equation for Tcl versus body weight across sexes.
• Upper critical temperature (Tcu) data were also considered in conjunction with Tcl and metabolic rate equations.

Conclusions:

• The derived equations provide a quantitative basis for understanding broiler energy metabolism and thermal requirements.
• Implementing environmental control strategies based on these equations can lead to maximal broiler performance.
• Optimized environments, informed by these metabolic and thermal models, can significantly reduce production costs in broiler farming.