Pre-slaughter Operations Research Articles

Poultry Preslaughter Operations in Hot Environments: The Present Knowledge and the Next Steps Forward.

Poultry production faces significant challenges, including high feed prices, diseases, and thermal stress, which impact broiler welfare and productivity. Despite advances in cooling technologies and ventilation, preslaughter operations still lead to considerable losses. This review highlights the need for the improved management of thermal environments and animal logistics. Preslaughter operations typically involve fasting broilers for 8-12 h to reduce gastrointestinal contents and contamination. Following fasting, broilers are caught, crated, and transported. Stress levels vary based on distance and conditions, with manual catching often causing stress and injuries. Catching should occur during cooler periods to minimise these issues, and transport conditions must be carefully managed. Lairage, the waiting period after transport, should be kept short (1-2 h) in climate-controlled environments to avoid stress and deterioration. Proper handling and efficient unloading are essential to prevent injuries and reduce economic losses. Stunning methods, such as electronarcosis and a controlled atmosphere, aim to minimise suffering before slaughter, though practices vary culturally and religiously. Logistics and real-time monitoring technology are crucial for enhancing animal welfare during transportation. Effective planning and the optimisation of transport processes is vital for reducing stress and losses, especially with regard to rising global temperatures and production demands.

Effect of three different lairage times (0, 18 and 24 hours) on meat quality parameters in camels

Animal stress has frequently been linked to pre-slaughter operations, particularly the transportation and handling process. Therefore, it is assumed that an optimal lairage time before slaughter will exert positive effects on the animal's welfare and meat quality. However, the impact of this practice on camels is unknown. This study aimed to assess the influence of three lairage durations: 0 h (L0), 18 h (L18), and 24 h (L24) on the quality of camel meat. Ninety adult male camels aged 6 years were included in this study. Longissimus lumborum was sampled to analyze for muscle glycogen, muscle pH (45 min; 48 h), muscle temperature (45 min; 48 h), electrical conductivity (45 min; 48 h), drip loss (DL), cooking loss (CL), and thawing loss (TL). The L24 group had the lowest (p < 0.05) of muscle glycogen and the highest ultimate pH (48 h). Further, the L24 group had the lowest muscle temperature, electrical conductivity, drip loss, and thawing loss (p < 0.05). In conclusion, a lairage period of 24 h is recommended in the field conditions studied here for full recovery from stress response caused by the pre-slaughter process and for achieving better camel meat quality.

Correlation between circulating cortisol and indicators of stress and oxidant stress during the preslaughter operations in camels

In livestock, pre-slaughter stress begins at the farm or market, continues during transport and upon arrival at the slaughterhouse, ending at slaughter. In this investigation, a survey was conducted in the slaughterhouse of Casablanca in Morocco to record the duration of the preslaughter operations and the frequency of urination in camels. Two groups of camels were constituted, the least stressed animals (Group I, n= 12) and the most stressed animals (Group II, n= 12). Group I animals had a waiting time before loading ≤ 24 h, a loading time ≤ 15 min, an unloading time ≤ 5 min, a water and food deprivation time before slaughter ≤ 24 h, a duration of accompaniment to the slaughter room ≤ 11 min and a frequency of urination during this accompaniment < 3 times. Those in group II had higher duration and frequency values for the same parameters. In addition, serum stress [cortisol (COR)], oxidant stress biomarkers [malondialdehyde (MDA)] and activities of catalase (CAT) and superoxide dismutase (SOD) were analyzed in both groups, and correlations between these biomarkers and the durations of various preslaughter operations and the frequency of urination were established. The most stressed camels (G II) showed high serum concentrations of COR and MDA, and low CAT and SOD activities by comparison to the less stressed camels (G I) (P<0.05). Significant correlations were recorded between COR, MDA, CAT and SOD, and the durations of various preslaughter operations, and between COR and the frequency of urination.

What slaughterhouse workers' attitudes and knowledge reveal about human-pig relationships during pre-slaughter operations: A profile-based approach

Slaughterhouse workers are strategic capital for the meat industry in terms of operational and animal welfare issues; however, information about the attitudes of workers toward the human-animal relationship is limited. The main aim of our study was to identify the profiles of workers based on their attitudes toward pigs, occupational satisfaction, sociodemographics, and animal handling. The survey included 171 workers in 12 Colombian pig slaughterhouses. A factor analysis and a hierarchical cluster analysis identified four segments or worker profiles. The first comprised workers who relate to animals and their work in a mechanical way, the second comprised professional workers who are emotionally close to animals, the third comprised those committed to animals and their work, and the fourth comprised workers who are apathetic toward animals and work activity. The human-animal relationship at the slaughterhouse level is multifaceted, but is influenced by dependent on work satisfaction and sympathy toward the animals.

Application of Electroencephalography in Preslaughter Management: A Review.

Simple SummaryPreslaughter stress has a negative impact on animal welfare, consumer acceptance, carcass, and meat quality. These preslaughter stressors include mishandling, the novelty of place and environment, social isolation, mixing with unfamiliar animals, knife sharpness, and slaughtering of animals in front of other animals (psychological/emotional stress). This is assumed to occur due to the ignorance and lack of awareness of the personnel involved in the industry, especially in developing countries. Previously, research has proven the impact of these factors by measuring neurohormonal and biochemical parameters. At the time of slaughter, these factors may have a greater influence on animals’ welfare in terms of pain during slaughter, as these hormonal-based methods often have a lag time following the stress or pain-induced change. A timely, rapid, and accurate pain assessment is crucial for proper animal welfare during slaughter. Electroencephalography measures the electric activity of the brain and pain instantaneously, accurately, and objectively. Various physiological and biochemical parameters are well correlated with the changes in EEG variables. The application of EEG in animal welfare studies has significantly enhanced our current scientific knowledge about pain perceptions, such as the effect of various non-noxious and noxious stimuli during slaughter.Electroencephalography (EEG) can be reliable for assessing the brain’s electrical activity of preslaughter stress and pain. The duration between the ventral neck cut and induction of a state of unconsciousness/insensibility is crucial in the slaughtering of animals, reducing pain, fear, and distress. Various EEG variables, such as median frequency (F50), the total power of EEG spectrum (Ptot), waves patterns (amplitude and frequencies), epileptiform EEG, index of consciousness, and isoelectric EEG, are used to identify a valid indicator of the state of unconsciousness. Association among various behavioral, physiological, and hematological parameters with EEG variables could provide an overall assessment and deep insights into the animal stress levels or welfare status during various managemental and preslaughter operations, such as transport, stunning, and slaughtering operations. The application of EEG could help in further refining the stunning technologies and slaughter protocols in livestock, poultry, and fish. The present review analyzed the application of EEG as a neurophysiological tool for assessing animal welfare during the critical state of preslaughter handling and slaughter, thus ensuring proper compliance with animal welfare principles.

Transcriptome profiling reveals stress-responsive gene networks in cattle muscles.

In meat-producing animals, preslaughter operations (e.g., transportation, mixing unfamiliar animals, food and water deprivation) may be a source of stress with detrimental effects on meat quality. The objective of this work was to study the effect of emotional and physical stress by comparing the transcriptomes of two muscles (M. longissimus thoracis, LT and M. semitendinosus, ST) in Normand cows exposed to stress (n = 16) vs. cows handled with limited stress (n = 16). Using a microarray, we showed that exposure to stress resulted in differentially expressed genes (DEGs) in both muscles (62 DEGs in LT and 32 DEGs in ST, of which eight were common transcription factors (TFs)). Promoter analysis of the DEGs showed that 25 cis transcriptional modules were overrepresented, of which nine were detected in both muscles. Molecular interaction networks of the DEGs targeted by the most represented cis modules helped identify common regulators and common targets involved in the response to stress. They provided elements showing that the transcriptional response to stress is likely to (i) be controlled by regulators of energy metabolism, factors involved in the response to hypoxia, and inflammatory cytokines; and (ii) initiate metabolic processes, angiogenesis, corticosteroid response, immune system processes, and satellite cell activation/quiescence. The results of this study demonstrate that exposure to stress induced a core response to stress in both muscles, including changes in the expression of TFs. These factors could relay the physiological adaptive response of cattle muscles to cope with emotional and physical stress. The study provides information to further understand the consequences of these molecular processes on meat quality and find strategies to attenuate them.

Impact of pre-slaughter factors on welfare of broilers

Pre-slaughter factors adversely affecting bird welfare were studied at the slaughterhouse. The incidence of dead on arrival (DoA), bruises and dehydration was investigated in 64 different mixed-sex batches of broilers coming from 64 different farms rearing fast-growing genotypes (Ross or Cobb). The effects of catching team, method of catching, time of day for catching and transport, density per cage, transport duration, transport distance, lairage duration and water withdrawal were considered. The average DoA was 0.29%, ranging from 0.02% to 1.89% per batch. DoA rate has a higher probability of increase with the increase in transport distance (t=2.142; P=0.037; estimate=0.009) and with catching the birds after midnight (t=-2.931; P=0.005; estimate=0.022). Longer transport durations for birds caught after midnight as well as longer lairage durations for birds caught after midnight are associated with the increase of DoA rate.Bruises were observed in 3.37% of birds, ranging from 0.43% to 8.29% per batch. Bruises occurred mostly on wings (3.06%), followed by legs (0.19%) and breast (0.12%). A higher percentage of bruises occurred in batches with more birds per transport crate (t=2.185; P=0.029; estimate=0.001). Dehydrated carcasses were observed in 22 out of 64 batches, accounting for 2.68% of condemnations. Signs of dehydration on carcasses were more frequently observed in batches subjected to longer withdrawal durations. Short transport distances, catching the birds before midnight and doing the transport by night are crucial in decreasing the DoA rate. Catching and crating processes seem to be responsible for the increase of percentage of bruises. Pre-slaughter operations should be adequate planned namely, transport and lairage durations, catching period and crating procedure in view to reduce negative effects on animal welfare.

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Animal welfare: impacts of pre-slaughter operations on the current poultry industry

Animal welfare: impacts of pre-slaughter operations on the current poultry industry

Bruises in beef cattle at slaughter in Mexico: implications on quality, safety and shelf life of the meat.

In emergent economies and developing countries of Africa, Asia and Latin America, the major cause for carcass rejection from the international market is bruising; nevertheless, many of these carcases are destined to local markets and meat processing industries for human consumption. Therefore, the aim of the present study was to assess the effect of bruised meat on pH, microbiologic count and biogenic amine (BA) profiles along 21days of ageing (sampling 1st, 7th, 14th and 21st day) with two packaging method (plastic bag vs vacuum) at 4°C. A total of 50 bruised carcasses were sampled from 1000 young bulls (Brown Swiss X Zebu) of 18-24months old and an average live weight of 450 ± 66kg. The results showed significant differences between packaging systems and bruised vs non-bruised meat. The bruised meat caused higher biogenic amine concentrations than did non-bruised meat. We conclude that bruised meat favoured increments of biogenic amine concentrations, even more than did non-bruised meat. The plastic bag + vacuum system limited the increments of BA concentration during storage time therefore it improved shelf life of meat. These results emphasized the importance of implementing best management practices during pre-slaughter operations of cattle in order to reduce a possible risk factor for bruised meat.

Main animal welfare problems in ruminant livestock during preslaughter operations: a South American view

Animals destined for meat production are usually exposed to many stressful conditions during production and particularly during preslaughter operations. Handling animals on farm, loading into and unloading from vehicles, transportation, passing through livestock markets, fasting, lairage and stunning can all affect their welfare. How badly welfare can be affected will depend on both the intrinsic factors of the specific type of animal involved and the extrinsic factors of the environment where those animals live or are being handled, including the animal handlers. In South America (SA), it has been part of a strategy for improving animal welfare (AW) to address not only ethical aspects, but to emphasize the close relationship existing between handling ruminants preslaughter and the quantity and quality of the meat they produce. This has resulted not only in improvements in AW, but has also brought economic rewards to producers which in turn can lead to higher incomes for them and hence better human welfare. For producers with a high number of animals, considering AW during production and preslaughter operations can determine the possibility of exporting and/or getting better prices for their products. At smallfarmer level, particularly in some less developed countries, where human welfare is impaired, using this strategy together with education has also been relevant. It is important that education and training in AW are done not only considering global knowledge, but also including specific geographical and climatic characteristics of each country and the cultural, religious and socio-economical characteristics of its people; therefore, research within the context of each country or region becomes relevant. The aim of this review was to show the results of research dealing with AW of ruminant livestock in Chile and some other SA countries. Some of the main problems encountered are related to lack of proper infrastructure to handle animals; long distance transport with high stocking densities in the larger countries; long fasting times due to animals passing through livestock markets and dealers; bad handling of animals by untrained personnel in these and other premises; and finally the lack of knowledge and skills by operators in charge of stunning procedures. Interventions at these stages have considered training animal handlers and transporters by showing them the consequences of bad handling with audiovisual material prepared on site. Research results have helped to improve AW and support the development of new legislation or to make changes in the existent legislation related to AW.

Pre-slaughter losses of broilers: effect of time period of the day and lairage time in a subtropical climate

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 lairage of broiler chickens, with adoption of increasing time intervals when lairage environment is controlled.

Modeling preslaughter mortality of broiler chickens using double generalized linear models

The aim of this study was to estimate parameters and design models for mortality prediction of broiler chickens in different preslaughter conditions, using the double generalized linear models. Preslaughter data from 13,937 broiler flocks were recorded daily during 2006, in a commercial slaughterhouse in Brazil. Several factors which influenced mortality rate were analysed, such as daily mean dry-bulb temperature and relative humidity, lairage time, daily periods, density of broilers per crate and season of the year. The data were analysed using a Double Generalized Linear Model, an extension of Generalized Linear Models (GLM), which provides a framework for modeling the dispersion in generalized linear models as well as the mean. As results, the double generalized linear models showed high accuracy for broiler mortality estimation, through interactions between the main factors which have influence on preslaughter operations.

A note on the effects of pre-slaughter operations of llamas (Lama glama) on the concentrations of some blood constituents related to stress and carcass quality

El objetivo de este trabajo fue evaluar el efecto de las operaciones presacrificio sobre indicadores fisiologicos de estres (constituyentes sanguineos) y de calidad de la canal (pH y contusiones) en llamas bajo condiciones comerciales. Treinta llamas criadas a pastoreo, de 18-24 meses de edad y peso vivo 54,2±6,4 kg fueron transportadas durante 3 h en un vehiculo a matadero. Se tomaron muestras de sangre a las llamas en predio una hora antes de cargar, despues de descargar, despues del reposo en matadero (18 h) y durante la exsanguinacion. Se encontro un aumento significativo (P < 0,05) de cortisol despues del transporte (16,9 ng/mL), como tambien de actividad de CK despues del reposo (528,4 UI/L); la concentracion de β -hidroxibutirato se mantuvo en los muestreos. Se registraron 19 contusiones en 9 de las 30 canales de llamas. Las lesiones superficiales, pequenas y de color rojo brillante, fueron las mas frecuentes. La region del lomo presento mas contusiones (57,89%), seguida del torax (21,05%). Las lesiones de forma irregular fueron mas frecuentes (81,25%), seguidas de circulares (18,75%). Se concluyo que las operaciones presacrificio de llamas bajo las condiciones comerciales del estudio produjeron cambios fisiologicos similares a los observados en otras especies, que caen dentro de limites aceptables para su bienestar; sin embargo, el estres y los efectos adversos en las canales, como las contusiones, podrian minimizarse mediante diseno de estructuras apropiadas para el manejo, aplicacion de las recomendaciones de OIE para el bienestar durante el sacrificio y capacitacion del personal que maneja las llamas a lo largo de la cadena carnica en Bolivia

Reducing pre-slaughter losses of broilers: crating density effects under different lairage periods at slaughterhouse

The aim of this work was to assess the effects of densities per crate on mortality rates of broilers during pre-slaughter operations, under different lairage time intervals. Pre-slaughter data from 13,937 broiler flocks were recorded daily during 2006, in a commercial slaughterhouse in southeastern Brazil.

Risk factors influencing bruising and high muscle pH in Colombian cattle carcasses due to transport and pre-slaughter operations

The aim of this study was investigate risk factors as possible causes for bruising and high muscle pH under commercial operating conditions in Colombia. Data was recorded for 86 journeys referring to 1179 animals. Carcasses were analyzed in terms of muscle pH and bruises (site, size, severity and shape). Our results indicate that truck load density, stops during transportation of cattle and the lairage time at the plant increased the risk of bruises appearing on carcasses. A lairage time of 18 to 24h at the plant increased the prevalence of bruises 2.1 times compared to lairage periods of between 12 and 18h. Furthermore, intermittent stops during transit are a risk factor for the increase in the incidence of bruises. However, the transport time (up to 4h) was not related to the presence of bruises and high muscle pH. Finally, steers were found to have less risk of presenting a high muscle pH.

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.

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.

Ambiência animal e as perdas produtivas no manejo pré-abate: o caso da avicultura de corte brasileira.

A evolução dos estudos sobre a ambiência na avicultura de corte tem alcançado patamares notáveis no que diz respeito às informações sobre a qualidade do ar, o ambiente térmico, acústico e lumínico nas diferentes fases de criação de frangos de corte. No entanto, pouca preocupação é dada à fase entre a retirada do animal da granja e o abate, ou seja, o manejo pré-abate, o que explica a elevada proporção de perdas produtivas nesta etapa. As informações sobre as condições ideais são escassas, principalmente considerando as condições climáticas críticas em regiões tropicais, como é o caso do Brasil. Consequentemente, as perdas por mortalidade pré-abate podem ultrapassar 1% ao longo do ano, resultando em grande prejuízo para todos os segmentos da cadeia avícola. Visando a redução de perdas nas operações pré-abate de frangos de corte, o levantamento de estudos e informações úteis é necessário, para que seja possível a padronização de procedimentos de manejo. O objetivo desta revisão é abordar pontos importantes que possam nortear a redução de perdas no manejo pré-abate da avicultura de corte, no que diz respeito aos fatores que influenciam nas perdas por mortalidade, no transporte de frangos da granja até o abatedouro, na espera no abatedouro e as principais soluções científicas desenvolvidas na ambiência e logística avícola.

Influence of Pre-Slaughter Process on Pork Quality: An Overview

Handling practices prior to slaughter have significant influence in the stress level and animal welfare of pigs, and consequently, in the final meat quality. This paper reviews current knowledge about ante mortem factors (fasting period, farm handling, mixing, loading, unloading, transport, lairage conditions, and driving to the stunner) related to the live animal that influence pork quality with special emphasis on technological quality attributes. The development in slaughter technologies and their practical applications in pig slaughterhouses are described. In spite of genetic effects and slaughter techniques, poor pre-slaughter operations lead frequently to an increase of physiological and physical stress in pigs. Ante mortem factors, such as lairage time or moving pigs into the slaughter rooms, and inadequate design of slaughterhouse facilities have an important effect on pig stress, affecting meat quality after slaughter. Some recommendations to guarantee animal welfare and obtain the best meat quality are reviewed.