Behavioral and physiological responses of different genetic lines of free-range broiler raised on a semi-intensive system

Abstract

The aim of the study was evaluate the ability of adaptation of seven different genetic lines of free-range broilers to a semi-intensive raising system. Four hundred and twenty chicks of the Pescoço Pelado (PP), Carijó (CG), Colorpak (CPK), Tricolor (TRC), Caboclo (CBC), Gigante Negro (GNG) and Pesadão Vermelho (PS) genetic groups were used. At 28 days of age the birds were allowed access the paddocks and after three days of adaptation the monitoring of the animals has started, being performed behavioral visual observations from 07:00 to 17:00. Cloacal temperature (CT) and respiratory rate (RR) were collected once a week. The environment was monitored considering the temperature, relative humidity and black globe temperature at various points of the paddocks and the shed. The physiological variables were evaluated using a randomized complete block design with a split plot arrangement. Behavioral variables were analyzed using nonparametric Friedman test. Birds of Carijó and Colorpak genetic line presented greater RR, 34.6 mov/min and 36.0 mov/min respectively, compared to the birds of the Caboclo and Gigante Negro genetic line, 29.0 mov/min and 28.4 mov/min respectively. The average values of RR and CT for all genetic lines were higher in the afternoon. At 7:00 and 17:00 the foraging behavior was more intense. The Caboclo and Gigante Negro genetic line were those that stood out in the behavior of foraging, consequently, they are more able to adapt to the semi-intensive raising system.

Performance and welfare of different genetic groups of laying hen

“…This behavior was observed mainly in Black hens because they are birds of a larger size and body weight. Gonçalves et al, (2017), observed an increase in movement of discomfort in lines with greater body weight (Carijó, Colorpak, Pesadão Vermelho, Tricolor) because they present greater sensitivity to the higher temperatures. Neme et al (2006) in the comparison between Hy-Line Brown and Hy-Line W36 strains, found that Hy-Line Brown in the morning spent more time eating, drinking, chasing, nesting, bathing sand and investigating feathers that line Hy-Line W36.…”

“…and Black Chicken 1,875 kg. As presented by Gonçalves (2017), animals of lower body mass have advantages in dissipating heat in relation to those of greater mass.…”

Computational Analysis of Load Ventilation in Broiler Transport

“…Unlike an inert load, the transport of live chickens is complex because chickens emit approximately 120W of heat (Kettlewell et al, 2001) and continuously adapt physiologically in an attempt to maintain their thermal balance through thermoregulatory mechanisms (Souza-Junior et al, 2019). The main thermal transfer route physiologically is the evaporative route, which can be seriously compromised by the elevation of the ambient temperature and accumulation of relative humidity of the air, in the microclimate in which it is inserted (Gonçalves et al, 2017). The renewal of air inside the load can be an efficient and viable solution to reduce/dissipate the accumulation of water vapor and thermal energy during livestock transport (Norton et al, 2013).…”

Broilers’ behavioural adjustments when submitted to natural heat stress and fed different maize particle sizes in the diet

“…In this type of environment, the thermal equilibrium of birds is affected since they do not have sweat glands (Egbuniwe et al ., 2018), leading to productive losses (Attia and Hassan, 2017; Silva et al ., 2017; Attia et al ., 2018). This thermal challenge motivates animals, especially broilers, to adjust their behaviour during the hottest times of day (Gonçalves et al ., 2017; El-Deek and El-Sabrout, 2019) in order to maximize the dissipation of excess body heat to avoid overheating (Egbuniwe et al ., 2018; Tickle and Codd, 2019), which causes mortality (Attia et al ., 2006; Pawar et al ., 2016).…”