Evaluation of losses and bioclimatic factors present on poultry preslaughter lairage condiction

Author(s)

Frederico Márcio Corrêa Vieira

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2008-06-11

Examining board members

Iran José Oliveira da Silva; Douglas Emygdio de Faria; Vicente Jose Maria Savino

• Advisor: Iran José Oliveira da Silva

Abstract

Nowadays, Brazilian poultry industry has a challenge of reducing losses. However, the disinformation about the critical points limits this advance, mainly on preslaughter operations. Therefore, studies must be carried through diagnosing scenes and identifying the critical points, which is found the biggest losses. Therefore, the objective of this work was to evaluate the climatization in lairage on slaughterhouse and its interactions with the lairage time, aiming to characterize the influence of environmental variables on thermal comfort, welfare and on the productive losses of broilers chickens. The study was developed in a commercial poultry abattoir, situated in the State of S~ao Paulo, Brazil. To the entire agreement of the problem, the research was divided in 3 parts, which the first stage was the historical evaluation of productive losses in function of the climatic variables and characteristics related to preslaugher operations, where historical data set of 13,937 trucks were analyzed about climatic factors and variables related to preslaughter stages, such as temperature and humidity, density of birds per cage, turn of the day and seasons of the year, as well as the lairage time. On the second stage, the effect of climatization and lairage time were evaluated on bird\'s thermal comfort in preslaughter lairage ambient, through the data collection of 218 trucks in the lairage module, where factors as the distance farm-abattoir and bioclimatic factors of the module were analyzed jointly with the variables registered previously, verifying the effect on mortality and on bird\'s rectal temperature alteration. On these two stages, the statistical analysis were carried out by the Double Generalized Linear Models. On the third stage, aiming at the complementation of previous stages informations, was done the recognition of standards related to preslaughter operations and to predict the losses by mortality through the use of Artificial Neural Network. More than 3,000 data of total set were used on the learning of neural nets models and on simulation of three scenes related to factors of mayor influence on preslaughter losses. As results, was verified that the biggest losses occurred during the afternoon, on summer, with densities of birds per cage above 8, high internal and external temperatures and relative humidity and to long distances. On generality, the increase of the lairage time results on reduction in the bird\'s rectal temperature and in mortality when external temperature is high, when density of birds per cage was major than 7 birds and to short distances. About the efficiency of climatization in the lairage shed, that was reached when external temperature and relative humidity were above the alert band and when internal climatic variables to the shed were in the comfort band. Related to neural network, these presented a great generalization power to the presented conditions, predicting satisfactorily the mortality of half of scenes, evidencing its use potential to the prediction of broiler chicken\'s mortality, submitted to preslaughter operations. (AU)