The Influence of Litter on Thermal Conditions inside a Broiler House

Grzegorz Nawalany,Waclaw Bieda

doi:10.5539/jas.v4n1p202

Abstract

The paper presents an analysis of the following measurements: litter temperature (QL), indoor air temperature (Qi) and ground temperature during the winter and summer broiler production cycles in real operating conditions of a mass scale broiler farm. The assessment of thermal conditions in the broiler living zone is widened by the parameter of operative temperature (Qo), taking into consideration not only Qi but also QL – the only partition that comes in direct contact with the birds. The paper also presents the percentage division of the researched area depending on the difference between optimal air temperature (Qopt) and litter temperature (QL) in the winter and summer production cycle. This is considered for three variations: QL < Qopt – 10-14-day period at the beginning of the production cycle characterized by the feeling of cold; QL = Qopt – middle and short period of thermal comfort and QL > Qopt – the longest, approx. 4-week period with the feeling of heat surplus. Daily fluctuation of QL =5-11 K in the winter season is much larger than in the summer season QL =1-3 K. Higher daily amplitude of QL favorably influences physical activity of birds and their thermal comfort. Moreover, the work describes the character of heat exchange between the litter and the ground, which from week 3 of the production cycle is favorable for thermal conditions by limiting the increase of QL to 33-34oC. It is the authors’ opinion that taking into consideration QL, the only partition that comes in direct contact with the birds, in the development of thermal conditions within the broiler living zone will inevitably lead to the improvement of breeding technology, which would answer to birds’ thermal preferences at various stages of the production cycle.

Highlights

Thermal conditions in the broiler living zone on a given day of the production cycle are most frequently evaluated by comparing air temperature inside the production hall ( i) with air temperature recommended by standards or producers’ instructions
For each of the 35 days of the winter and summer production cycle, the proportion of litter area with L was defined compared to operative air temperature: L < opt; L = opt and L > opt, which were presented in figures 4a and 4b
A small isofield of thermal comfort L = opt appears in day 5 and in such a scope maintains until the 20th day of the production cycle

Summary

Introduction

Thermal conditions in the broiler living zone on a given day of the production cycle are most frequently evaluated by comparing air temperature inside the production hall ( i) with air temperature recommended by standards or producers’ instructions ( opt).Specialist literature which enumerates significant microclimate parameters of broiler houses does not always mention thermal radiation of partition walls coming in direct contact with the birds. Thermal conditions in the broiler living zone on a given day of the production cycle are most frequently evaluated by comparing air temperature inside the production hall ( i) with air temperature recommended by standards or producers’ instructions ( opt). It is not surprising that the influence of litter on thermal conditions in the broiler living zone is often disregarded. The research revealed that, irrespective of time of year, at the beginning of the broiler production cycle, litter temperature ( L) is definitely lower than i, even by 6.5-13.5 K; afterwards, a short period of thermal comfort i = L ensues; whilst in the last three weeks of the cycle, L is much higher than i, even by 13-16 K (Nawalany et al, 2004).

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