The preslaughter handling and transport of broilers are stressful operations that might affect welfare and meat quality and could increase numbers of deaths before slaughter. However, the influence of thermal factors during transportation and lairage at slaughterhouses is complex in subtropical regions, where increasing temperature and high RH are the major concerns regarding animal survival before slaughter. In this study we assessed the influence of a controlled lairage environment on preslaughter mortality rates of broiler chickens that were transported during different seasons of the year and had varying lairage times in the subtropical climate. Preslaughter data from 13,937 broiler flocks were recorded daily during 2006 in a commercial slaughterhouse in southeastern Brazil. The main factors that influenced daily mortality rate were mean dry bulb temperature and RH, lairage time, daily periods, density of broilers per crate, season of the year, stocking density per lorry, transport time, and distance between farms and slaughterhouse. A holding area at the slaughterhouse with environmental control was assessed. Using a double GLM for mean and dispersion modeling, the seasons were found to have significant effects (P < 0.05) on average mortality rates. The highest incidence was observed in summer (0.42%), followed by spring (0.39%), winter (0.28%), and autumn (0.23%). A decrease of preslaughter mortality of broilers during summer (P < 0.05) was observed when the lairage time was increased, mainly after 1 h of exposure to a controlled environment. Thus, lairage for 3 to 4 h in a controlled lairage environment during the summer and spring is necessary to reduce the thermal load of broiler chickens.

A produção de carne de frango no Brasil é um dos setores mais importantes do agronegócio, sendo que a expansão e manutenção dos mercados externos estão diretamente relacionadas com a qualidade do produto final. Um dos grandes problemas no sistema de produção de frangos, esta relacionado com a logística de distribuição e conseqüentemente as formas de transporte de cargas vivas. Nesta pesquisa objetivou-se determinar a classificação do nível de perdas produtivas na carga viva de frangos de corte, utilizando como ferramenta de decisão a lógica fuzzy. Após a avaliação das informações de entrada no sistema fuzzy verificou-se que o modelo obtido é importante por dois fatores: o primeiro pela classificação clara e direta das condições de transporte e segundo pela perspectiva de estabilidade ou não das condições classificadas, mostrando o potencial de mudança das mesmas, o que poderá ser utilizada como objeto de atenção para a escolha de estratégias de transporte. SUMMARYThe poultry industry at Brazil is one of the most important sectors of agribusiness, which expansion and maintenance of the international markets are directly linked with the final product quality. One of the major problems on the poultry production system is related with distribution logistics and consequently with the types of livestock transport. In this research, the objective was to determine the classification of productive losses levels on the poultry transport, using as decision tool the fuzzy logic. After the assessment of input information on fuzzy system, it was verified that the developed model is important due two reasons: firstly, to the clear and direct classification of transport conditions, and secondly to the perspective of the stability or not of the assorted condition, showing this potential for change, which may be used with the aim to pay attention during the choose of transport strategies. INTRODUÇÃOA preocupação com o bem estar de frangos de corte nas operações pré-abate é crescente, com destaque em regiões tropicais. Apesar de outros fatores influírem nas perdas produtivas, como as injúrias e traumas provenientes da pega e do carregamento, distância entre as granjas e o abatedouro, vibração do caminhão e restrição de água, os fatores térmicos correspondem cerca de 40 % das perdas totais (Ritz et al., 2005).No transporte, há uma variação térmica por volta de 2 a 5 ºC entre o microclima interno das caixas e o ambiente externo (Mitchell e Kettlewell, 1998). Esses fatores,