Productive Responses From Broiler Chickens Raised in Different Commercial Production Systems - Part I: Fuzzy Modeling

Abstract

Broiler chickens are classified as homoeothermic animals and require a production environment within well-defined thermal comfort intervals. Therefore, the development of algorithms (mathematical models) to control the environment that can be embedded in microcontrollers becomes necessary. Hence, this work aimed to develop a fuzzy model for predicting the productive performance of broiler chickens as a function of the thermal environment during the various breeding phases. The Mamdani inference and defuzzification methods were used, by means of the gravity center, to develop the fuzzy model. Two hundred and forty-three rules with weighting factors of 1.0 each were elaborated. Three commercial warehouses (conventional system, wind tunnel with negative pressure and dark house) were evaluated for testing of the model. We recorded the thermal environment (dry bulb temperature-tdb and relative humidity-RH) and productivity data (feed intake-FI, weight gain-WG, feed conversion-FC and productive efficiency index-PEI) over six lots in each aviary. The resulting fuzzy model was capable of forecasting FI, WG, FC, and PEI, with standard deviations and mean percentage errors of 4.16 g and 5.05%, 146.53 g and 8.04%, 0.06 g g-1 and 4.96%, and 24.51 g and 12.29%, respectively.

Performance of broilers submitted to different intensities and duration of thermal stress

“…The lowest FC value associated with t db of 30°C is in agreement with literature, given that this temperature is considered as thermal comfort for broilers in the second week of life [5,23].…”

“…For t db of 33°C, as the duration of thermal stress increases, it was verified the reduction in the effect of t db in FI at 21 days of the birds' age, indicating the occurrence of adaptation of the broilers to the stress environment. It is also verified that t db of 33°C applied to thermal stress duration of 2, 3 and 4 days, does not yet represent a condition of significant discomfort (p>0.05, Scott-Knott test) for broilers when compared to the condition recommended in the literature as of comfort (t db = 30°C) [5,23].…”

“…In Table 1, it can be observed that the thermal stress was applied in four duration (1, 2, 3 and 4 days) in the first four days that compose the second week (8th, 9th, 10th and 11th days of life). Soon after this period the t db returned to the recommended value as characteristic of the thermal comfort zone (30°C) [5,23].…”

Spatial variability of enthalpy and illuminance in free-range broiler sheds

“…Thus, it can be concluded that the internal environment of the sheds was out of the comfort conditions for broilers during the entire trial period, demonstrating the importance of the study of thermal comfort in the facilities, as well as the application of different techniques to improve animal welfare Ribeiro et al, 2016;Sampaio et al, 2018;Coelho et al, 2019;Lourençoni et al, 2019).…”

Efficiency of cooling systems in broiler houses during hot days

“…In this study, we used weather forecasts to select days with extreme temperatures and a high risk of heat stress, as the inside environment of the most vulnerable facilities can reflect the outside environmental conditions. Expert systems such as fuzzy logic, data mining, and artificial neural networks (VALE et al, 2010;JHA et al, 2019;LOURENÇONI et al, 2019) can be used to develop warning systems based on weather forecasts (ACEVEDO & FITZJARRALD, 2003;MARTO, 2005;CARDOSO et al, 2010). These models assist in the decision-making of specific actions, such as adding potassium chloride supplementation in drinking water (AHMAD et al, 2008), environmental modifications (e.g., activation of cooling systems), and nutritional strategies (e.g., restriction of feed and fat addition) (see review: NAWAB et al, 2018) for minimizing broiler mortality on high-temperature days (VALE et al, 2008).…”