Afrânio Márcio Corrêa Vieira

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

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.

Productive losses on broiler preslaughter operations: effects of the distance from farms to abattoirs and of lairage time in a climatized holding area

This work aimed to assess the effects of preslaughter lairage time on the welfare and mortality of broilers transported in different farm-abattoir distances. It was evaluated 215 poultry transport trucks from a commercial poultry slaughterhouse from 2006 to 2007. Data were obtained from the holding area acclimatized through fans and water misting in the mornings, afternoons and at night. The thermal variables (temperature and relative humidity), distance, lairage time and density of birds per cage were considered in the analysis. The effects of distance and lairage time were important in the variation of rectal temperature of the animals and on the number of dead animals per truck. Two models were developed (mean and dispersion), for each response variable in function of the interaction between lairage time and distance. As the lairage time in the holding area increased, the rectal temperature of the birds was reduced for all the studied distances. In farm-abattoir distances higher than 25 km, mortality was low when lairage time was lower than 1 hour. However, for distances below 25 km, in the same time interval, the number of dead birds was two-fold higher than in the first situation. The adjustment of lairage time has to be done accordingly to the distance provided that the lairage environment is correctly climatized.

Thermal stress related with mortality rates on broilers' preslaughter operations: a lairage time effect study

Concerning the reduction of preslaughter death losses, high temperature and relative humidity in the tropics are the major concerns regarding broiler survival prior slaughtering. However, the relationship between different lairage times under controlled environment and the thermal condition outside the holding area is still unclear. Thus, the aim of this study was to compare different intervals of lairage time with different environmental temperature and relationship with poultry mortality rates. A study was conducted in a commercial poultry abattoir in the State of Sao Paulo, Brazil, in the year of 2006. The historical data set from 13,937 trucks, about broiler mortality during preslaughter operations, was given by the abattoir. Factors that influence the welfare of birds were studied, such as lairage time in abattoir and hourly dry-bulb temperature. The statistical analysis was performed using the Double Generalized Linear Models. The lower incidence of death losses before arrival at the processing plant (approximately 13 dead birds per truck) was observed when the lairage time was between 1 to 3 hours, under high temperatures (above 22°C). This effect was more pronounced under critical (25-28°C) and lethal intervals (above 29°C) (12 and 13 dead birds per truck, respectively). In relation to lairage time, the reduction in mortality rates was more pronounced in the intervals up to 1 hour of lairage under climatized conditions, with a reduction of 3 dead birds per truck. It was concluded that thermal stress have negative influence for broilers welfare kept under preslaughter conditions and variations on mortality rate are strongly related with different lairage times.

Transporte de ovos férteis: Influência das idades das matrizes, tempos de estocagem e das estradas

The aim of this study was to assess the influence of age of breeder hens and storage periods on number of cracked eggs during transportation on different types of roads. The study was conducted in a poultry farm located in Mogi-Mirim, State of Sao Paulo, Brazil, through tracking of three loads in different seasons of the year (spring, summer and autumn). An environmentally controlled truck was used, with total capacity of 592 egg boxes. Vibration levels (m s-2) and shocks during asphalt and land track were registered by accelerometers (n = 4). The number of cracked eggs was obtained through visual accounting of 18 egg boxes, which showed three breeder ages and three storage periods. A completely randomized experimental design was adopted, with a 3 x 3 factorial design. It is concluded that old and intermediate broiler breeders showed a higher number of cracked eggs. The higher vibration levels and load shocks were observed towards horizontally. The asphalt road offered harsh conditions for egg transportation.

Níveis de vibração e choques em diferentes estradas durante o transporte de ovos férteis

The levels of vibration and shock due to transport can affect the quality of fertile eggs. The aim of this study was to characterize and to evaluate the influence of roads on the levels of vibration and shock in the transport of fertile eggs. The survey was conducted in the poultry integrator company in the State of Sao Paulo, by tracking shipments in three different seasons (spring, summer and autumn). An air-conditioned trunk was used, with a capacity of 592 boxes of eggs, totaling an average of 90,840 eggs. The evaluation of vibration levels (m s-2) and shocks on unpaved and asphalt roads were recorded by four accelerometers brand Hobo. For the vibration level, the experimental design was completely randomized in a 3 x 2 x 4 factorial. For the number of shocks the experimental design was completely randomized with a factorial 3 x 2. The worst levels of vibration and shock load occurred in the vertical direction. The asphalt road provided the worst conditions for the transport of eggs. The transport losses exceeded 1%, which are attributed to cracks and breakage of eggs.

Double generalized linear model for tissue culture proportion data: A Bayesian perspective

Joint generalized linear models and double generalized linear models (DGLMs) were designed to model outcomes for which the variability can be explained using factors and/or covariates. When such factors operate, the usual normal regression models, which inherently exhibit constant variance, will under-represent variation in the data and hence may lead to erroneous inferences. For count and proportion data, such noise factors can generate a so-called overdispersion effect, and the use of binomial and Poisson models underestimates the variability and, consequently, incorrectly indicate significant effects. In this manuscript, we propose a DGLM from a Bayesian perspective, focusing on the case of proportion data, where the overdispersion can be modeled using a random effect that depends on some noise factors. The posterior joint density function was sampled using Monte Carlo Markov Chain algorithms, allowing inferences over the model parameters. An application to a data set on apple tissue culture is presented, for which it is shown that the Bayesian approach is quite feasible, even when limited prior information is available, thereby generating valuable insight for the researcher about its experimental results.

Modelización de la mortalidad previo al sacrificio de pollos con modelos lineales generalizados doble - DOI:10.5039/agraria.v9i2a3178

El objetivo de este estudio fue estimar parametros y disenar modelos para predecir la mortalidad de pollos de engorde en distintas condiciones de pre abate, utilizandose de un modelo linear generalizado doble. Datos del pre abate de 13.937 pollos fueron colectados diariamente durante el ano de 2006 en un matadero comercial en Brasil. Distintos factores que tienen influencia sobre la tasa de mortalidad fueron analizados, como la media de temperatura de bulbo seco y humedad relativa del aire, tiempo de estabulacion, periodos diarios, densidad de los pollos por caja y estaciones del ano. Los datos fueron analizados utilizandose del Modelo Linear Generalizado Doble, una extension del Modelo Linear Generalizado (MLG), que proporciona un marco para el modelado de la dispersion en los modelos lineares generalizados y tambien la media. Como resultado, el modelaje linear generalizado doble demostro una alta precision para estimar la tasa de mortalidad de pollos de engorde, a traves de las interacciones entre los principales factores que influyen en las operaciones antes del abate de los animales.

Thermoregulatory responses of day-old chickens submitted to simulated transport condition: effect of exposure time under different thermal ranges.

In this study, we assessed the thermoregulatory responses of day-old chickens exposed to different dry-bulb temperature and relative humidity ranges and varying exposure times, under simulated condition of transport. In this experiment, Cobb 500 1-day-old chicks (n = 900), were exposed to a thermoneutral (35°C; relative humidity 60%), cold stress (20°C; 75%) and heat stress (38°C; 75%) treatments during three time intervals (0, 3 and 6 hours), in a climatic chamber. Those animals were obtained from a commercial hatchery, from selected eggs which were stored and incubated in the same conditions. Female broiler breeders were about 41 weeks old. The animals were placed in boxes (n=3) for day-old chicks transport, divided in 100 chicks per box, and each box was intercalated with empty boxes, all stacked vertically, for each thermal treatment. Body weight, respiratory rate, body surface temperature, mortality rate and cloacal temperature were monitored in a sample of 5 animals per box after the time interval treatment. The thermal profile inside the climatic chamber was monitored through temperature, relative humidity and specific enthalpy. A completely randomized design was adopted and the treatment structure was a 3 x3 factorial design (3 thermal ranges and 3 time intervals). Data were analysed by ANOVA and means differing significantly were separated by the Tukey’s test procedure. It can be concluded that the heat stress during day-old chicks was the most stressful condition, considering physiological and mortality responses. Also, these responses were more aggravated after 3 hours of exposition to harsh environmental conditions.

Caracterização fuzzy do transporte pré-abate de frangos de corte: uma abordagem qualitativa

The poultry industry at Brazil is one of the most important sectors of agribusiness, which expansion and maintenance of the international markets are directly linked with the final product quality. One of the major problems on the poultry production system is related with distribution logistics and consequently with the types of livestock transport. In this research, the objective was to determine the classification of productive losses levels on the poultry transport, using as decision tool the fuzzy logic. After the assessment of input information on fuzzy system, it was verified that the developed model is important due two reasons: firstly, to the clear and direct classification of transport conditions, and secondly to the perspective of the stability or not of the assorted condition, showing this potential for change, which may be used with the aim to pay attention during the choose of transport strategies.

Bioclimatic Evaluation of Gestating Sows housed in Bedding and Concrete Floor Systems

Abstract: Regarding to heat stress at animal facilities, the use of bedding and pig production might be meaning of trouble, besides that, there is few literature talking about this type of system during the gestation. The objective of this work was to verify the effect of using shallow wood shavings bedding to improve the thermal comfort in gestating sows when they are housed at different systems during the gestation period. 1) full-period group housing + shallow wood shavings bedding; 2) full-period group housing + concrete floor (no bedding); 3) group housing after 28 days of gestation in the cage + shallow wood shavings bedding and 4) group housing after 28 days of gestation in the cage + concrete floor (no bedding). Rectal temperature (RT) and superficial temperature (ST) responses of gestating sows were taken during 8 periods at 3 days by 3 different hours per day. Environmental variables were taken using the same methodology. Bedding utilization has increased mean air temperature and enthalpy inside the facilities. Means of enthalpy showed values of 55.25kJ/kgdry air (shallow wood shavings bedding) and 52.88kJ/ kgdry air (concrete floor). However, rectal temperature has not changed doing the bedding system. On the other hand, the superficial temperature on the head showed higher when bedding treatment was applied compared back to concrete floor (34.47C and 33.947C, respectively). The superficial temperature of the shoulder, loin and ham have showed statistical significance (P<0.05) between bedding effect and housing systems, then, bedding showed higher values. The range of temperature for thermal comfort was changed since bedding was used. It was possible to conclude that for using bedding during summer time there is some disadvantages during gestation period for sows. However, this system should be analyzed in general, emphasizing alternative ways to minimize loss by heat stress at tropical conditions.