Preslaughter mortality of broilers in relation to lairage and season in a subtropical climate

Abstract

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.

On oxidation resistance and meat quality of broilers challenged with lipopolysaccharide

“…However, selection for these economically important traits has been accompanied by an increase in the number of problems encountered during the intensive production system, especially birds are easily susceptive to a variety of stressors (Cheng et al 2004). This situation may affect bird welfare as well as increase stress-related diseases, resulting in poor performance, high mortality and inferior meat quality (Ngoka et al 1982;Sackett et al 1986;Küchenmeister et al 2002;Ferguson & Warner 2008;Young et al 2009;Vieira et al 2011). Lipopolysaccharide (LPS) isolated from Escherichia coli bacteria is recognized by immune cells as a pathogen-associated molecular pattern and activates innate immune responses.…”

Influência das condições térmicas do galpão de espera climatizado na mortalidade pré-abate de frangos de corte

“…O aumento de 1ºC na temperatura do ar correspondeu ao aumento de 0,09U de variabilidade da mortalidade. A explicação para esse fato refere-se à heterogeneidade térmica existente ao longo da carga no caminhão de transporte e ao ambiente de espera no abatedouro, de acordo com trabalhos anteriores (Simões et al, 2009;Silva e Vieira, 2010 Vieira et al (2011b), os quais afirmaram que as condições térmicas são pouco variáveis nesse período, ou seja, a temperatura é mais elevada e, com isso, o conforto e o bemestar para as aves são críticos. A mortalidade é elevada nesse período e pouca variação dentro dessa faixa é observada nessa situação.…”

Pre-slaughter losses of broilers: effect of time period of the day and lairage time in a subtropical climate

“…The main factors in this study were the time of the day (morning, afternoon, or nighttime) and lairage time. Lairage time was considered as the time between the truck's arrival at the lairage platform and the unloading of the crates onto the slaughter platform, which was categorized as short (less than 1 hour), moderate (between 1 and 2 hours), medium (between 2 and 3 hours), and long (more than 3 hours), according to the previous studies performed by Vieira et al (2011).…”