Factors Influencing Milk Quality and Subclinical Mastitis in Dairy Herds Housed in Compost-Bedded Pack Barn System.

The compost-bedded pack barn (CBPB) system has been increasingly adopted by dairy farms due to its ability to enhance animal comfort and milk production. This study evaluated the associations among bedding characteristics, milk quality and composition, and subclinical mastitis (SCM) occurrence in dairy herds housed in CBPB systems. Over a period of six months, data related to milk quality and udder health and bedding sampling were collected from eight dairy farms. Monthly measurements of the bedding temperature and wind speed inside the CBPB were taken, while temperature and relative humidity data inside the CBPB were recorded using a datalogger. Bedding samples were subjected to analysis of moisture, pH, microbiological count, and carbon/nitrogen ratio. Data on milk composition (fat, protein, milk urea nitrogen, and total solids) and quality (somatic cell count and standard plate count) of bulk tank milk were obtained from DHIA results. Canonical correlation analyses were used to evaluate the association between the analyzed group variables, and linear regression models were used to identify associations between bedding characteristics and SCM occurrence in the studied herds. The bedding characteristics that most influenced milk composition and quality were moisture, temperature at 30 cm depth (T30), and bedding pH. Environmental variables played an important role in bedding composting, as they were closely related to the surface temperature and pH. Overall, 62.71% of the variation in milk quality and composition could be explained by the bedding variables, and 77.50% of the variation in the bedding variables was associated with environmental variables. Median SCM prevalence and incidence were 28.6 and 13.8%, respectively. An increase of 1 °C for T30 resulted in a 0.6% reduction in the prevalence of SCM. Additionally, the bedding surface temperature at 22.3 °C resulted in the highest incidence of SCM (~18.1%). Our results demonstrate the importance of controlling microclimatic conditions in the CBPB to optimize the bedding composting process and milk quality.

Effects of Heat Stress in Dairy Cows Raised in the Confined System: A Scientometric Review.

Due to climate change, heat stress is a growing problem for the dairy industry. Based on this, annual economic losses in the dairy sector are verified mainly on a large scale. Despite several publications on thermal stress in lactating dairy cows in confinement systems, there need to be published reviews addressing this issue systematically. Our objective was to scientometrically analyze the effects of heat stress in dairy cows managed in a confinement system. Based on PRISMA guidelines, research articles were identified, screened, and summarized based on inclusion criteria for heat stress in a confinement system. Data was obtained from the Web of Science. A total of 604 scientific articles published between 2000 and April 2022 were considered. Data was then analyzed using Microsoft Excel and CiteSpace. The results pointed to a significant increase in studies on heat stress in lactating cows housed in confinement systems. The main research areas were Agriculture, Dairy Animal Science and Veterinary Sciences. The USA showed the highest concentration of studies (31.12%), followed by China (14.90%). Emerging themes included heat stress and behavior. The most influential journals were the Journal of Dairy Science and the Journal of Animal Science. The top authors were L. H. Baumgard and R. J. Collier. The leading institutions were the Chinese Academy of Agricultural Sciences, followed by the State University System of Florida and the University of Florida. The study maps the significant research domains on heat stress of lactating cows in confinement systems, discusses implications and explanations and highlights emerging trends.

Placental Development and Physiological Changes in Pregnant Ewes in Silvopastoral and Open Pasture Systems during the Summer.

This study aimed to analyze the reproductive and physiological changes in ewes subjected to heat stress during pregnancy at UTFPR-Brazil. Twenty-four pregnant crossbred ewes were kept in a silvopastoral system (SP) or an open pasture system (OP) throughout the final trimester of pregnancy. Both systems were stressful, but the SP system had lower air temperature than the OP system (26.0 ± 0.38 and 26.9 ± 0.41 °C, respectively; p = 0.0288). Moreover, the radiant thermal load of the two groups presented a difference of 34 Wm-2 (p = 0.0288), and the grass temperature was also lower in the SP system compared to that in the OP system (23.4 ± 0.37 and 25.6 ± 0.44 °C, respectively; p = 0.0043). The respiratory and heart rates of animals from the OP group were higher than those from the SP group (p < 0.001), but no difference was observed in the mobilization of white blood cells (p = 0.4777), and the neutrophil count was only affected by time (p < 0.0001). As regards placental biometry, placentas in twin pregnancies had a greater membrane area (p = 0.0223), but no differences between the systems were observed in placental weight (p = 0.1522) and the number of cotyledons (p = 0.5457). We concluded that the type of rearing system used affects the thermal comfort of pregnant ewes, and that an SP system can offer more amenable microclimatic conditions, which result in greater comfort for the ewes.

A systematic review of the effects of silvopastoral system on thermal environment and dairy cows' behavioral and physiological responses.

Does the silvopastoral system (SPS) promote a satisfactory thermal environment for dairy cows to perform their natural behaviors and perform a suitable thermoregulatory function? To answer this, peer-reviewed articles, written in English and evaluating the effects of silvopastoral systems on thermal environment, dairy cows' behavior, and physiology were used in this systematic review; additionally, a bibliometric approach was performed. Web of Science and Google Scholar were used to compile the literature. The resulting articles (1448) underwent a 4-step appraisal process and resulted in 19 articles that fitted our inclusion criteria. Microclimate variables and thermal comfort indicators were the most researched topics (discussed in 89% of studies); 47% of studies addressed cattle behavior and 36% physiological responses. Our review highlights different benefits of silvopastoral systems for grazing dairy cows. For example, the SPS provides a more comfortable thermal environment than treeless pasture, which increases feeding behaviors; furthermore, dairy cows in SPS show lower drinking events, surface temperature, and respiratory rate than cows raised in treeless pasture. However, for nine of the variables related to cows' behavior (e.g., resting, rumination) and physiology responses (e.g., internal temperature), the results of the studies were unclear. Furthermore, behaviors associated with lying down (e.g., idling and rumination) and milk production in SPS were explored only in six and two studies, respectively. These findings provide consistent evidence that the silvopastoral systems are beneficial to thermal comfort of dairy cows; nonetheless, the effect on cows' behavioral and physiological responses is still scarce and unclear.

Compost Dairy Barn Layout and Management Recommendations in Kentucky: A Descriptive Study.

This study was conducted to describe the building layout and dimensions, characterize the bedding material, and observe the management practices in 42 compost-bedded pack (CBP) barns in Kentucky (USA). The average herd size found in the study was 90 cows and the breeds consisted of Jersey (6.8%), Holstein (72.7%), and mixed (20.5%). The average CBP barn dimensions were 49.1 m (length) by 21.9 m (width). Many of these barns had feed alleys and driveways; overshot ridges with frequent orientation from NE to SW; and green sawdust, kiln-dried sawdust, or a mixture of both as the most common bedding materials. The bed-turning process was performed mechanically at depths of less than 0.25 m, and the loading of fresh material was performed every one to five weeks, varying by season, weather conditions, barn size, and cow density. The average bedding moisture content was found to be 59.0% (wet bulb-w.b.) and ranged from 36.2 to 71.8%. Coliforms were not present in barns that had a higher compost temperature, and the E. coli, Bacillus, and Streptococcus counts were higher in the barns that had a lower moisture content. In conclusion, it was observed that heterogeneous management was used among the barns and that the producers were satisfied with the compost barn system.

The Welfare of Dairy Cows in Pasture, Free Stall, and Compost Barn Management Systems in a Brazilian Subtropical Region.

The effect of milk production systems on the welfare of dairy cows has been studied worldwide, but studies that compare pasture-based, compost barn, and free stall systems, according to animal welfare, are more scarce. In this work, the welfare of 51 dairy herds, including 17 from each management system, was investigated through the application of the Welfare Quality® protocol. Descriptive statistics and the Kruskal-Wallis non-parametric method were used to analyze variables. In the present work, the welfare of the evaluated herds was significantly better in the pasture-based system than in the confinement systems. However, the pasture-based system presented weaknesses in providing water resources. The compost barn had fewer animal welfare critical points than the free stall system, as well as it was better than the free stall in measures related to comfort and health. The free stall did not present better scores than the other systems. It is concluded that the welfare of dairy cows is affected by the rearing system, with better scores, in most measures, in the pasture-based system, followed by the compost barn and, finally, the free stall.

Determination of Thermal, Chemical and Physical Properties of Bedding Materials for Compost Dairy Barns.

The thermal, chemical, and physical properties of compost bedding materials play an important role in every phase of compost production. Based on this, we aimed to assess the thermal, chemical and physical properties of bedding materials for compost-bedded pack (CBP) barns. The database for this study was registered from 42 CBP barns, distributed throughout the state of Kentucky (USA). The thermal conductivity showed a linear relationship with moisture content and bulk density, while thermal resistivity decreased with increasing particle size. The bedding moisture average was 46.8% (±11.5). The average finer index (p < 0.05) was the highest weight percentage (30.1%) in the samples studied. Water-holding capacity (WHC) increased with increasingly fine particle size. The higher bulk density value was 3.6 times that of the lowest bulk density value. The chemical characterization of the bedding material provided the following results: 42.7% (±3.8%) C, 1.6% (±0.4%) N, and 28.2 (±8.0) C:N ratio. However, thermal properties are strongly dependent on particle size. Producers can use the bedding material as fertilizer in their crops, due to the chemical characteristics of the materials. Beds with good physical and chemical properties improve their moisture content.

Spatio-Thermal Variability and Behaviour as Bio-Thermal Indicators of Heat Stress in Dairy Cows in a Compost Barn: A Case Study.

The spatial variability and behavioural aspects of compost-bedded pack barns remain unknown in subtropical regions. In this study, we investigated whether spatial variability occurs in the thermal environment of a compost barn and how the behaviour of dairy cows with different numbers of lactations differs in this system. The spatial sampling design comprised a grid of 108 locations inside the facility. At each location, we measured air temperature, relative humidity, wind speed, and bed temperature at 9:00, 12:00, and 15:00. We performed 24-h behavioural observations. Regarding spatial variability, the north face showed high air temperature values, and the distribution of relative humidity varied from the north to the south face. Kriging maps revealed a high bedding temperature trend, indicating heterogeneous ventilation management. Primiparous cows visited the water trough during the hottest hours of the day, whereas multiparous cows displayed a higher probability of walking during these periods. In conclusion, we observed a heterogeneous management of ventilation through the spatial distribution of the thermal environment inside the compost-bedded pack barn, with multiparous cows exhibiting dominance over primiparous cows seeking environmental resources.

Microclimate in an agro-ecological silvopastoral system with bamboo at different tree-shade projection distances: a case study in Southern Brazil / Microclima em sistema silvipastoril agroecológico com bambu em diferentes distâncias de projeção de sombra: um estudo de caso no Sul do Brasil

The aim of the present study was to evaluate the ability of an agro-ecological silvopastoral system, composed of bamboo and tree species, to promote microclimatic alterations at different projection distances from the canopy of trees. A total of 16 paddocks in an agro-ecological silvopastoral system were evaluated. The paddocks were divided into four separate groups (silvopastoral treatments): a) Bambusa vulgaris L. and planted trees, b) only bamboo, c) only trees, and d) open grassland system. The following microclimate parameters were studied: air temperature, relative humidity, grass temperature and wind speed. All parameters were measured at a height of 20 cm above the soil. The measurements were recorded by different time intervals, in order to examine the effect of three factors: time of day, silvopasture treatment and distance to the row of trees. The results show that there was an increase in relative humidity and a reduction in wind speed close to the tree line. The agro-ecological silvopastoral system acts therefore as a windbreaker and retains humidity close to the trees. Thus, it can be concluded that regardless of the presence of bamboo, due to the limited canopy area at young stage of B. vulgaris, the agro-ecological silvopastoral system promoted microclimatic alterations to the environment, indicating the potential of this integrated system to reduce the heat load for livestock and plants.

O objetivo do presente estudo foi avaliar a capacidade de um sistema silvipastoril agroecológico, composto por espécies de bambu e árvores, em promover alterações microclimáticas a diferentes distâncias de projeção a partir do dossel das árvores. Um total de 16 piquetes em um sistema silvipastoril agroecológico foram avaliados. Os piquetes foram divididos em quatro grupos separados (tratamentos silvipastoris): a) Bambusa vulgaris L. e árvores plantadas, b) somente bambu, c) somente árvores, e d) sistema de pastagem aberta. Os seguintes parâmetros do microclima foram estudados: temperatura do ar, umidade relativa do ar, temperatura da grama e velocidade do vento. Todos os parâmetros foram medidos a uma altura de 20 cm acima do solo. As medidas foram registradas por diferentes intervalos de tempo, a fim de examinar o efeito de três fatores: horário do dia, tratamento da silvipastoril e distância até a fileira de árvores. Os resultados mostram que houve aumento na umidade relativa e uma redução na velocidade do vento próximo à linha de árvores. O sistema silvipastoril agroecológico age, portanto, como um quebra-vento e retém a umidade perto das árvores. Assim, pode-se concluir que, independente da presença de bambu, devido à limitada área de copa em estágio jovem de B. vulgaris, o sistema silvipastoril agroecológico promoveu alterações microclimáticas ao ambiente, indicando o potencial deste sistema integrado de reduzir a carga de calor para gado e plantas.

Probability distributions for frequency analysis of rainfall at southwest region of Paraná state, Brazil / Distribuições de probabilidade para análise de frequência de chuva no sudoeste do Paraná

The study of monthly rainfall probabilities is of great importance due to the increasing occurrences of extreme events in different regions of Brazil. However, the rainfall distribution at the southwest region of Paraná State, Brazil, is still unknown. Thus, the aim of this work is to assess the probabilistic distribution of rainfall frequency at Dois Vizinhos, in the southwest of Paraná State, Brazil. A probabilistic analysis was performed using a historic 40-year rainfall dataset (1973-2012). The gamma, Weibull, normal log, and normal probability distributions were compared. The distribution adherence was performed through Akaike Information Criterion, and the R statistical software was used for estimation. The results showed that the gamma and Weibull distributions were most suitable for probabilistic fitting. Based on this, the average annual rainfall for Dois Vizinhos (PR) was found to be 2,010.6 mm. Moreover, we found that throughout the year, October has the highest rainfall occurrence probability, with an 86% rainfall probability of above 150 mm and 64% rainfall probability above 200 mm.

O estudo de probabilidades mensais de precipitação pluvial torna-se importante em virtude do aumento de ocorrências de eventos extremos em diversas regiões do país. Entretanto, poucas informações são conhecidas a respeito da distribuição de chuva na região do sudoeste do Paraná. Com base no exposto objetivou-se por meio desta pesquisa analisar a distribuição probabilística mensal da precipitação pluvial na região de Dois Vizinhos, sudoeste do estado do Paraná. Analisou-se a série histórica de precipitação pluvial de 40 anos (1973-2012). Foram comparadas as seguintes distribuições de probabilidade: gama, Weibull, log normal e normal. A aderência das distribuições aos dados pluviométricos da região foi verificada através do critério de Akaike (AIC). As análises foram realizadas utilizando o software estatístico R. Por meio dos resultados observou-se que as distribuições de gama e Weibull foram as mais adequadas em termos de ajustes probabilísticos. Com base nas distribuições, a média anual de chuva na região de Dois Vizinhos é de 2.010,6 mm e o mês de outubro registra a maior probabilidade de ocorrência de precipitação, sendo 86% de probabilidade de chuvas acima de 150 mm e 64% acima de 200 mm.

Probability distributions for frequency analysis of rainfall at southwest region of Paraná state, Brazil / Distribuições de probabilidade para análise de frequência de chuva no sudoeste do Paraná

The study of monthly rainfall probabilities is of great importance due to the increasing occurrences of extreme events in different regions of Brazil. However, the rainfall distribution at the southwest region of Paraná State, Brazil, is still unknown. Thus, the aim of this work is to assess the probabilistic distribution of rainfall frequency at Dois Vizinhos, in the southwest of Paraná State, Brazil. A probabilistic analysis was performed using a historic 40-year rainfall dataset (1973-2012). The gamma, Weibull, normal log, and normal probability distributions were compared. The distribution adherence was performed through Akaike Information Criterion, and the R statistical software was used for estimation. The results showed that the gamma and Weibull distributions were most suitable for probabilistic fitting. Based on this, the average annual rainfall for Dois Vizinhos (PR) was found to be 2,010.6 mm. Moreover, we found that throughout the year, October has the highest rainfall occurrence probability, with an 86% rainfall probability of above 150 mm and 64% rainfall probability above 200 mm.(AU)

O estudo de probabilidades mensais de precipitação pluvial torna-se importante em virtude do aumento de ocorrências de eventos extremos em diversas regiões do país. Entretanto, poucas informações são conhecidas a respeito da distribuição de chuva na região do sudoeste do Paraná. Com base no exposto objetivou-se por meio desta pesquisa analisar a distribuição probabilística mensal da precipitação pluvial na região de Dois Vizinhos, sudoeste do estado do Paraná. Analisou-se a série histórica de precipitação pluvial de 40 anos (1973-2012). Foram comparadas as seguintes distribuições de probabilidade: gama, Weibull, log normal e normal. A aderência das distribuições aos dados pluviométricos da região foi verificada através do critério de Akaike (AIC). As análises foram realizadas utilizando o software estatístico R. Por meio dos resultados observou-se que as distribuições de gama e Weibull foram as mais adequadas em termos de ajustes probabilísticos. Com base nas distribuições, a média anual de chuva na região de Dois Vizinhos é de 2.010,6 mm e o mês de outubro registra a maior probabilidade de ocorrência de precipitação, sendo 86% de probabilidade de chuvas acima de 150 mm e 64% acima de 200 mm.(AU)

Microclimate in an agro-ecological silvopastoral system with bamboo at different tree-shade projection distances: a case study in Southern Brazil / Microclima em sistema silvipastoril agroecológico com bambu em diferentes distâncias de projeção de sombra: um estudo de caso no Sul do Brasil

The aim of the present study was to evaluate the ability of an agro-ecological silvopastoral system, composed of bamboo and tree species, to promote microclimatic alterations at different projection distances from the canopy of trees. A total of 16 paddocks in an agro-ecological silvopastoral system were evaluated. The paddocks were divided into four separate groups (silvopastoral treatments): a) Bambusa vulgaris L. and planted trees, b) only bamboo, c) only trees, and d) open grassland system. The following microclimate parameters were studied: air temperature, relative humidity, grass temperature and wind speed. All parameters were measured at a height of 20 cm above the soil. The measurements were recorded by different time intervals, in order to examine the effect of three factors: time of day, silvopasture treatment and distance to the row of trees. The results show that there was an increase in relative humidity and a reduction in wind speed close to the tree line. The agro-ecological silvopastoral system acts therefore as a windbreaker and retains humidity close to the trees. Thus, it can be concluded that regardless of the presence of bamboo, due to the limited canopy area at young stage of B. vulgaris, the agro-ecological silvopastoral system promoted microclimatic alterations to the environment, indicating the potential of this integrated system to reduce the heat load for livestock and plants.(AU)

O objetivo do presente estudo foi avaliar a capacidade de um sistema silvipastoril agroecológico, composto por espécies de bambu e árvores, em promover alterações microclimáticas a diferentes distâncias de projeção a partir do dossel das árvores. Um total de 16 piquetes em um sistema silvipastoril agroecológico foram avaliados. Os piquetes foram divididos em quatro grupos separados (tratamentos silvipastoris): a) Bambusa vulgaris L. e árvores plantadas, b) somente bambu, c) somente árvores, e d) sistema de pastagem aberta. Os seguintes parâmetros do microclima foram estudados: temperatura do ar, umidade relativa do ar, temperatura da grama e velocidade do vento. Todos os parâmetros foram medidos a uma altura de 20 cm acima do solo. As medidas foram registradas por diferentes intervalos de tempo, a fim de examinar o efeito de três fatores: horário do dia, tratamento da silvipastoril e distância até a fileira de árvores. Os resultados mostram que houve aumento na umidade relativa e uma redução na velocidade do vento próximo à linha de árvores. O sistema silvipastoril agroecológico age, portanto, como um quebra-vento e retém a umidade perto das árvores. Assim, pode-se concluir que, independente da presença de bambu, devido à limitada área de copa em estágio jovem de B. vulgaris, o sistema silvipastoril agroecológico promoveu alterações microclimáticas ao ambiente, indicando o potencial deste sistema integrado de reduzir a carga de calor para gado e plantas.(AU)

Environment, behavior and welfare aspects of dairy cows reared in compost bedded pack barns system

The compost bedded pack barns is a loose housing confinement system for dairy cows, which aims to provide greater comfort in the resting area. Therefore, objective of this review was to investigate the environment, behavior and welfare aspects of dairy cows in the compost bedded pack barns system. The system is characterized by the large collective bed area, in which the objective is the composting of that area. In this way, the ideal bed management is the key point to the success of this system. In addition to daily revolving, an efficient ventilation system is required to perform the air exchange in the shed, and maintain adequate bed humidity levels, while maintaining a comfortable dry environment for the cows to lie down. The ventilation system also has great importance in the cows thermal comfort. In seasons of high average temperatures, ventilation reduces possible stress situations, raising the animals welfare level. Another characteristic of compost bedded pack barns is the greater spacing per animal in the bed area, allowing animals to express naturally the behavior of lying down and decrease the competition among animals. The compost bedded pack barns system presents the potential to provide comfort and welfare for dairy cows. However, good bed management and microclimatic environmental conditions are necessary. However, further studies are needed at the national level to provide more information on the ideal management of the system under climatic conditions in Brazil and the cows behavior in the system.(AU)

Environment, behavior and welfare aspects of dairy cows reared in compost bedded pack barns system

The compost bedded pack barns is a loose housing confinement system for dairy cows, which aims to provide greater comfort in the resting area. Therefore, objective of this review was to investigate the environment, behavior and welfare aspects of dairy cows in the compost bedded pack barns system. The system is characterized by the large collective bed area, in which the objective is the composting of that area. In this way, the ideal bed management is the key point to the success of this system. In addition to daily revolving, an efficient ventilation system is required to perform the air exchange in the shed, and maintain adequate bed humidity levels, while maintaining a comfortable dry environment for the cows to lie down. The ventilation system also has great importance in the cows’ thermal comfort. In seasons of high average temperatures, ventilation reduces possible stress situations, raising the animals’ welfare level. Another characteristic of compost bedded pack barns is the greater spacing per animal in the bed area, allowing animals to express naturally the behavior of lying down and decrease the competition among animals. The compost bedded pack barns system presents the potential to provide comfort and welfare for dairy cows. However, good bed management and microclimatic environmental conditions are necessary. However, further studies are needed at the national level to provide more information on the ideal management of the system under climatic conditions in Brazil and the cows’ behavior in the system.

Pre-slaughter losses of broilers: effect of time period of the day and lairage time in a subtropical climate / Perdas pré-abate de frangos de corte: efeito dos períodos diários e do tempo de espera em clima subtropical

Mortality losses of broilers during pre-slaughter operations consists of actual challenge for maintaining world leadership of Brazilian poultry industry. In relation to thermal environment and its influence on abattoirs handling, some studies has advanced about the knowledge of these variables on poultry welfare. However, few studies was developed in subtropical conditions, considering a joint analysis of involved thermal factors. In this context, the aim of this work was to assess the mortality of broiler chickens transported throughout daily periods and submitted to different lairage time intervals. A trial was conducted in a commercial slaughterhouse at São Paulo state, during 2006. More than 13,000 loads was registered regarding broiler mortality data during pre-slaughter operations, as well as factors which had influence on losses, such as daily periods, lairage time and bioclimatic variables. Higher mortality rates of broiler transportation were registered during afternoon, around 13 birds per truck. Regarding the interaction between daily periods and lairage time at abattoir, during morning and afternoon, the mortality rate was reduced when birds were submitted to a lairage time of two hours in a controlled environment. These results showed the high level of pre-slaughter losses during hottest periods and the importance of environment control during pre-slaughter...(AU)

As perdas por mortalidade nas operações pré-abate de frangos de corte constituem-se desafios atuais na manutenção da liderança do setor avícola brasileiro no cenário mundial. Com relação ao ambiente térmico e sua influência no manejo em abatedouros, algumas pesquisas têm avançado quanto ao entendimento destas variáveis no bem-estar das aves. Entretanto, poucos estudos foram realizados em condições subtropicais, considerando a análise conjunta dos fatores térmicos envolvidos. Neste contexto, objetivou-se avaliar a mortalidade de frangos de corte, transportados ao longo dos períodos diários e submetidos aos diferentes intervalos de tempo de espera em abatedouro. A pesquisa foi conduzida em um abatedouro comercial no Estado de São Paulo, no ano de 2006. Mais de 13 mil caminhões foram registrados quanto aos dados de mortalidade de frangos de corte durante as operações pré-abate, bem como os fatores influentes nas perdas, tais como os períodos do dia em que as aves foram transportadas, tempo de espera pré-abate e variáveis bioclimáticas. Durante o período da tarde foram registradas as maiores proporções de mortalidade durante o transporte, ou seja, em torno de 13 aves por caminhão. Quanto à interação entre períodos diários e tempo de espera em abatedouro, durante o período da manhã e tarde, a mortalidade foi menor quando as aves foram submetidas ao tempo de espera acima de duas hora...(AU)

Pre-slaughter losses of broilers: effect of time period of the day and lairage time in a subtropical climate / Perdas pré-abate de frangos de corte: efeito dos períodos diários e do tempo de espera em clima subtropical

Mortality losses of broilers during pre-slaughter operations consists of actual challenge for maintaining world leadership of Brazilian poultry industry. In relation to thermal environment and its influence on abattoirs handling, some studies has advanced about the knowledge of these variables on poultry welfare. However, few studies was developed in subtropical conditions, considering a joint analysis of involved thermal factors. In this context, the aim of this work was to assess the mortality of broiler chickens transported throughout daily periods and submitted to different lairage time intervals. A trial was conducted in a commercial slaughterhouse at São Paulo state, during 2006. More than 13,000 loads was registered regarding broiler mortality data during pre-slaughter operations, as well as factors which had influence on losses, such as daily periods, lairage time and bioclimatic variables. Higher mortality rates of broiler transportation were registered during afternoon, around 13 birds per truck. Regarding the interaction between daily periods and lairage time at abattoir, during morning and afternoon, the mortality rate was reduced when birds were submitted to a lairage time of two hours in a controlled environment. These results showed the high level of pre-slaughter losses during hottest periods and the importance of environment control during pre-slaughter...

As perdas por mortalidade nas operações pré-abate de frangos de corte constituem-se desafios atuais na manutenção da liderança do setor avícola brasileiro no cenário mundial. Com relação ao ambiente térmico e sua influência no manejo em abatedouros, algumas pesquisas têm avançado quanto ao entendimento destas variáveis no bem-estar das aves. Entretanto, poucos estudos foram realizados em condições subtropicais, considerando a análise conjunta dos fatores térmicos envolvidos. Neste contexto, objetivou-se avaliar a mortalidade de frangos de corte, transportados ao longo dos períodos diários e submetidos aos diferentes intervalos de tempo de espera em abatedouro. A pesquisa foi conduzida em um abatedouro comercial no Estado de São Paulo, no ano de 2006. Mais de 13 mil caminhões foram registrados quanto aos dados de mortalidade de frangos de corte durante as operações pré-abate, bem como os fatores influentes nas perdas, tais como os períodos do dia em que as aves foram transportadas, tempo de espera pré-abate e variáveis bioclimáticas. Durante o período da tarde foram registradas as maiores proporções de mortalidade durante o transporte, ou seja, em torno de 13 aves por caminhão. Quanto à interação entre períodos diários e tempo de espera em abatedouro, durante o período da manhã e tarde, a mortalidade foi menor quando as aves foram submetidas ao tempo de espera acima de duas hora...