Influência de diferentes sistemas de criação na produção de frangos de corte industrial com ênfase no bemestar animal

Abstract

The general objective of this research is to evaluate three housing systems for broiler chickens production, aiming to characterize the thermal environment and the variables that may influence in the production system, determining the conditions favorable to better animal performance, based on indicators of welfare as response to the environment they are growing. The experiment was conducted in a production cycle of 42 days, in the city of Carpina, state of Pernambuco, at the Experimental Station for Small Animals of the Federal Rural University of Pernambuco (UFRPE). The survey was developed in four production modules, divided in four boxes with 10 birds per box, totaling 15 boxes, submitted to the three housing systems: semi-confined with 3 m2/broiler of paddock area (SC 3), semiconfined with 6 m2/broiler of paddock area (SC 6) and total confinement (CONF). The experiment was carried out into three stages, depending on the data evaluation: bioclimatic analysis, behavioral analysis and production systems analysis. The bioclimatic evaluation was performed through the record of physiological parameters respiratory rate (mov.min-1) and cloacal temperature (°C) and the meteorological variables, dry bulb temperature (Tbs;oC), wet bulb temperature (Tbu; oC) and black globe temperature (Tg; oC) registered in both the production modules and the external environment, which allowed characterization of thermal efficiency, the black globe humidity index (ITGU) and enthalpy (h). For birds performance evaluation, 6 random birds were chosen in each system, totaling 18 birds to the appraisal, 3 birds per box, in three replicates of each separate system of accommodation in hourly intervals from 7:00 to 8:00AM, 10:00 to 11:00AM, 01:00 to 02:00PM and 04:00 to05:00PM, registering the behavior in a spreadsheet with the behavioral relation every 5 min. The analysis of the production system resulted in the following zootechnical indices as variable answers to the housing systems (feed consumption, CR; weight gain, GP; feedconversion, CA; body weight, PV) and carcass yield and slaughtering. The experimental design for data general analysis was completely randomized (CRD), in split plots, being the weeks allocated in the plots and the accommodation systems (SC 3, SC 6, CONF and EXT)in the sub-plots with the averages compared through the Tukey test. The meteorological variables and comfort indexes indicated the semi-confined system of accommodation SC 3 as one that allowed better natural conditioning heat to the birds, presenting the average values of 25.4 °C, 69.9 kJ kg-1 and 75.7 for Tbs, h and ITGU, respectively. Physiological parameters respiratory rate (mov.min-1) and cloacal temperature (C) had average values more appropriate in birds subjected to the semi-confined accommodation system SC 3, in response to lower heat stress, with a value higher in 38% of the considered normal condition of 40 mov.min-1 compared to the other systems of accommodation that had an increase of 44% for respiratory rate. For cloacal temperature there were not values that outperformed the temperatures considered normal for broiler chickens, between 41 and 42 °C in all accommodation systems. The housing systems did not promote significant changes in performance and improvement of broiler chickens, assuming that the birds with access to the paddock at 21 days of age showed no negative effect on productivity. The birds subjected to the semi-confined system SC 3 were those that had better opportunity to express their natural behavior and explore the external environment to the module of production, leveraging the animal welfare.