Influence of loading handling and facilities on the subsequent response to pre-slaughter stress in pigs

Validation of the slaughterhouse porcine heart model for ex-situ heart perfusion studies

INTRODUCTION

To validate slaughterhouse hearts for ex-situ heart perfusion studies, we compared cold oxygenated machine perfusion in less expensive porcine slaughterhouse hearts (N = 7) to porcine hearts that are harvested following the golden standard in laboratory animals (N = 6).

METHODS

All hearts received modified St Thomas 2 crystalloid cardioplegia prior to 4 hours of cold oxygenated machine perfusion. Hearts were perfused with homemade modified Steen heart solution with a perfusion pressure of 20-25 mmHg to achieve a coronary flow between 100-200 mL/min. Reperfusion and testing was performed for 4 hours on a normothermic, oxygenated diluted whole blood loaded heart model. Survival was defined by a cardiac output above 3 L with a mean aortic pressure above 60 mmHg.

RESULTS

Both groups showed 100% functional survival, with laboratory hearts displaying superior cardiac function. Both groups showed similar decline in function over time.

CONCLUSION

We conclude that the slaughterhouse heart can be used as an alternative to laboratory hearts and provides a cost-effective method for future ex-situ heart perfusion studies.

Utilizing productivity and health breeding-to-market information along with disease diagnostic data to identify pig mortality risk factors in a U.S. swine production system

Aggregated diagnostic data collected over time from swine production systems is an important data source to investigate swine productivity and health, especially when combined with records concerning the pre-weaning and post-weaning phases of production. The combination of multiple data streams collected over the lifetime of the pigs is the essence of the whole-herd epidemiological investigation. This approach is particularly valuable for investigating the multifaceted and ever-changing factors contributing to wean-to-finish (W2F) swine mortality. The objective of this study was to use a retrospective dataset ("master table") containing information on 1,742 groups of pigs marketed over time to identify the major risk factors associated with W2F mortality. The master table was built by combining historical breed-to-market performance and health data with disease diagnostic records (Dx Codes) from marketed groups of growing pigs. After building the master table, univariate analyses were conducted to screen for risk factors to be included in the initial multivariable model. After a stepwise backward model selection approach, 5 variables and 2 interactions remained in the final model. Notably, the diagnosis variable significantly associated with W2F mortality was porcine reproductive and respiratory syndrome virus (PRRSV). Closeouts with clinical signs suggestive of Salmonella spp. or Escherichia coli infection were also associated with higher W2F mortality. Source sow farm factors that remained significantly associated with W2F mortality were the sow farm PRRS status, average weaning age, and the average pre-weaning mortality. After testing for the possible interactions in the final model, two interactions were significantly associated with wean-to-finish pig mortality: (1) sow farm PRRS status and a laboratory diagnosis of PRRSV and (2) average weaning age and a laboratory diagnosis of PRRS. Closeouts originating from PRRS epidemic or PRRS negative sow farms, when diagnosed with PRRS in the growing phase, had the highest W2F mortality rates. Likewise, PRRS diagnosis in the growing phase was an important factor in mortality, regardless of the average weaning age of the closeouts. Overall, this study demonstrated the utility of a whole-herd approach when analyzing diagnostic information along with breeding-to-market productivity and health information, to measure the major risk factors associated with W2F mortality in specified time frames and pig populations.

Effect of lairage time prior to slaughter on stress in pigs: a path analysis

BACKGROUND

Pre-slaughter process during transportation, handling, and lairage causes stress in pigs, affecting animal welfare and meat quality. Therefore, lairage factors are important for relieving stress. A total of 24 LYD (Landrace × Yorkshire × Duroc) barrows were used to investigate the effect of 6 and 20 h lairage time (LT) on cortisol, serotonin, and catecholamine in blood and physiological factors in muscle, and to verify the causal relationship between these factors.

RESULTS

The results revealed that cortisol was increased (0.064 ± 0.007 µg/ml), and epinephrine (0.020 ± 0.002 µg/ml) and norepinephrine (1.518 ± 0.071 µg/ml) were lower at a LT of 20 h than those at 6 h, and there was no significant effect on the muscle and carcass characteristic factors. In addition, cortisol and norepinephrine showed a negative correlation (r = -50,346, p = 0.0121), epinephrine and glycogen had a positive correlation (r = 0.4417, p = 0.0307), and serotonin and heat shock protein 70 (HSP70) were positively correlated (r = 0.4715, p = 0.0200). Path analysis indicated that the increase in LT had a direct effect on cortisol, epinephrine, and norepinephrine, and an indirect effect on muscle glycogen.

CONCLUSION

This study confirmed the effect of the increase in LT from 6 to 20 h in the lairage room on the stress response of pigs. These findings support the legal requirements that advocate for shorter lairage times, in alignment with enhanced animal welfare standards.

Identification of intestinal and fecal microbial biomarkers using a porcine social stress model

Understanding the relationships between social stress and the gastrointestinal microbiota, and how they influence host health and performance is expected to have many scientific and commercial implementations in different species, including identification and improvement of challenges to animal welfare and health. In particular, the study of the stress impact on the gastrointestinal microbiota of pigs may be of interest as a model for human health. A porcine stress model based on repeated regrouping and reduced space allowance during the last 4 weeks of the finishing period was developed to identify stress-induced changes in the gut microbiome composition. The application of the porcine stress model resulted in a significant increase in salivary cortisol concentration over the course of the trial and decreased growth performance and appetite. The applied social stress resulted in 32 bacteria being either enriched (13) or depleted (19) in the intestine and feces. Fecal samples showed a greater number of microbial genera influenced by stress than caecum or colon samples. Our trial revealed that the opportunistic pathogens Treponema and Clostridium were enriched in colonic and fecal samples from stressed pigs. Additionally, genera such as Streptococcus, Parabacteroides, Desulfovibrio, Terrisporobacter, Marvinbryantia, and Romboutsia were found to be enriched in response to social stress. In contrast, the genera Prevotella, Faecalibacterium, Butyricicoccus, Dialister, Alloprevotella, Megasphaera, and Mitsuokella were depleted. These depleted bacteria are of great interest because they synthesize metabolites [e.g., short-chain fatty acids (SCFA), in particular, butyrate] showing beneficial health benefits due to inhibitory effects on pathogenic bacteria in different animal species. Of particular interest are Dialister and Faecalibacterium, as their depletion was identified in a human study to be associated with inferior quality of life and depression. We also revealed that some pigs were more susceptible to pathogens as indicated by large enrichments of opportunistic pathogens of Clostridium, Treponema, Streptococcus and Campylobacter. Generally, our results provide further evidence for the microbiota-gut-brain axis as indicated by an increase in cortisol concentration due to social stress regulated by the hypothalamic-pituitary-adrenal axis, and a change in microbiota composition, particularly of bacteria known to be associated with pathogenicity and mental health diseases.

Cold Oxygenated Machine Perfusion Improves Functional Survival of Slaughterhouse Porcine Hearts

The aim of our study was to explore the effect of cold oxygenated machine perfusion in slaughterhouse porcine hearts on functional myocardial survival compared to static cold storage (SCS). Seventeen hearts were harvested from Dutch Landrace Hybrid pigs, which were sacrificed for human consumption and randomly assigned to the 4 hours SCS group (N = 10) or the 4 hours cold oxygenated machine perfusion group (N = 7). Hearts were perfused with a homemade Heart Solution with a perfusion pressure of 20-25 mm Hg to achieve a coronary flow between 100 and 200 ml/minute. After 4 hours of preservation, all hearts were functionally assessed during 4 hours on a normothermic, oxygenated diluted whole blood (1:2) loaded heart model. Survival was defined by a cardiac output above 3 L with a mean aortic pressure above 60 mm Hg. Survival was significantly better in the cold oxygenated machine perfusion group, where 100% of the hearts reached the 4 hours end-point, as compared with 30% in the SCS group ( p = 0.006). Interestingly, warm ischemic time was inversely related to survival in the SCS group with a correlation coefficient of -0.754 ( p = 0.012). Cold oxygenated machine perfusion improves survival of the slaughterhouse porcine heart.

Field Implementation of Forecasting Models for Predicting Nursery Mortality in a Midwestern US Swine Production System

The performance of five forecasting models was investigated for predicting nursery mortality using the master table built for 3242 groups of pigs (~13 million animals) and 42 variables, which concerned the pre-weaning phase of production and conditions at placement in growing sites. After training and testing each model's performance through cross-validation, the model with the best overall prediction results was the Support Vector Machine model in terms of Root Mean Squared Error (RMSE = 0.406), Mean Absolute Error (MAE = 0.284), and Coefficient of Determination (R2 = 0.731). Subsequently, the forecasting performance of the SVM model was tested on a new dataset containing 72 new groups, simulating ongoing and near real-time forecasting analysis. Despite a decrease in R2 values on the new dataset (R2 = 0.554), the model demonstrated high accuracy (77.78%) for predicting groups with high (>5%) or low (<5%) nursery mortality. This study demonstrated the capability of forecasting models to predict the nursery mortality of commercial groups of pigs using pre-weaning information and stocking condition variables collected post-placement in nursery sites.

Welfare of pigs during transport

In the framework of its Farm to Fork Strategy, the Commission is undertaking a comprehensive evaluation of the animal welfare legislation. The present Opinion deals with protection of pigs during transport. The welfare of pigs during transport by road is the main focus, but other means of transport are also covered. Current practices related to transport of pigs during the different stages (preparation, loading/unloading, transit and journey breaks) are described. Overall, 10 welfare consequences were identified as highly relevant for the welfare of pigs during transport based on the severity, duration and frequency of occurrence: group stress, handling stress, heat stress, injuries, motion stress, prolonged hunger, prolonged thirst, restriction of movement, resting problems and sensory overstimulation. These welfare consequences and their animal‐based measures are described. A variety of hazards were identified, mainly relating to factors such as mixing of unfamiliar pigs, inappropriate handling methods and devices, the use of pick‐up pens, inexperienced/untrained handlers, structural deficiencies of vehicles and facilities, poor driving conditions, unfavourable microclimatic and environmental conditions and poor husbandry practices leading to these welfare consequences. The Opinion contains general and specific conclusions relating to the different stages of transport of pigs. Recommendations to prevent hazards and to correct or mitigate welfare consequences are made. Recommendations were also developed to define quantitative thresholds for microclimatic conditions and minimum space allowance within means of transport. The development of the welfare consequences over time was assessed in relation to maximum journey duration. The Opinion covers specific animal transport scenarios identified by the European Commission relating to transport of cull sows and ‘special health status animals’, and lists welfare concerns associated with these.

Effect of distance and daily periods on heat-stressed pigs and pre-slaughter losses in a semiarid region

Effective planning animal transport is essential to safeguard animal welfare and reduce production losses. Environmental conditions, specifically extreme temperatures in combination with ranges of relative humidity are highlighted as one of the main risk factors for production losses during transport (e.g., fatalities). The majority of research evaluating both welfare and production impacts of pig transport have been primarily undertaken in Europe and North America, which cover a relatively limited range of distinct climates (e.g., temperate, sub-arctic, etc.). As a result, research on pig transport in semi-arid conditions is lacking. In this study, we evaluated the effects of both distance (short, 30 km; and long, 170 km) and transport daily periods (morning, (05:00-11:00); afternoon (12:00-17:00); and night, (23:00-04:00)) on the preslaughter losses and heat stress of pigs in commercial transport in a semiarid region. Across 19 journeys of standard slaughter-weight pig loads (124.0 ± 2.8 kg), 684 focal animals (36 per journey) were evaluated. For each journey, the load's thermal profile (THI_adj and enthalpy) and physiological responses of individual pigs were recorded. On arrival at designated slaughterhouses, the percentage pig of non-ambulatory non-injured (NANI), non-ambulatory injured (NAI), death on arrival (DOA), and total losses were recorded. Short journeys in the afternoon were shown to be more detrimental to the thermal comfort of pigs, with higher rectal temperatures recorded. The highest percentage of total losses and DOA occurred in afternoon journeys, irrespective of distance, followed by the morning, with the lowest losses observed in pigs transported at night. Additionally, total losses and DOA were further exacerbated by journey distance, with higher rates observed in short journeys. Higher percentage averages of NANI and NAI were observed in shorter journeys, but daily periods effects were only observed for NANI. These results further demonstrate the welfare and production loss risks associated with journey distance and time of day (representing varying environmental conditions) during road transport of pigs, whilst providing novel data in semiarid conditions. Careful and effective planning for pig transportation is essential to minimize heat stress and production losses. Consideration of the thermal environment on the day of travel, as well as providing flexibility to adjust travel times (e.g., early morning or evening), should help to mitigate risks of heat stress and production losses during pig transport.

Evidence-Based Recommendations for Herd Health Management of Porcine Post-Weaning Diarrhea

Simple Summary

In this paper, you will find recommendations on how to prevent post-weaning diarrhea in pigs kept in indoor pig herds. The recommendations are based on the scientific knowledge that is currently available. The authors first validated that Danish veterinarians working with pigs demanded such recommendations. Then, we collected papers written by other researchers who had summarized the scientific knowledge on different topics related to post-weaning diarrhea. From the papers, we extracted and synthesized 79 specific recommendations that may help veterinarians and pig producers make good decisions for their pig herd. The paper exemplifies a novel approach to summarizing and transferring science into practice that may be of interest to people that are not involved with pigs and post-weaning diarrhea.

Abstract

Aided by their advising veterinarians, pig producers need to make difficult decisions regarding herd health management strategies. For instance, the preventive use of antimicrobials and medicinal zinc oxide must be substituted with more sustainable preventive approaches to porcine post-weaning diarrhea. Veterinarians and pig producers may find assistance in knowledge based on evidence in this regard; however, the overwhelming scientific literature is not always readily available. The overall aim of this paper is to suggest herd health management decision-support tools that can aid veterinary-assisted decision making in the control of porcine post-weaning diarrhea at a tactical level. The first objective was to validate the need for a herd health management concept, including two decision-support tools. The second objective was to develop evidence-based recommendations that can aid veterinary-assisted decision-making for the herd health management of post-weaning diarrhea. The first objective was investigated by a questionnaire-based study among veterinary pig practitioners in Denmark. For the second objective, we conducted a scientific summary based on scientific review papers identified through a systematic search in three databases. From the papers, we synthesized and extracted 79 specific recommendations. In this paper, we report comprehensive evidence-based recommendations for the herd health management of post-weaning diarrhea.

Use of two novel trailer types for transportation of pigs to slaughter. 2. Effects on trailer microclimate, pig behaviour, physiological response, and meat quality under Canadian winter conditions

In total, 3,654 market pigs were transported to slaughter in winter (six replicates/treatment; January-February in southwestern Ontario) using three trailers: a modified triple-deck pot-belly (MPB), an advanced flat-deck (AFD) trailer, and a standard pot-belly (SPB). Within trailers, ambient conditions, temperature (T°C), relative humidity (RH%) and temperature and humidity index (THI), were monitored in three compartments (bottom front, BF, middle middle deck, MM, and top rear, TR). In total, 324 pigs were selected for the analysis of hematocrit, lactate, and creatine kinase (CK) levels in exsanguination blood and for the evaluation of pork quality as assessed in the longissimus (LM), semimembranosus (SM), and adductor (AD) muscles. The SPB trailer overall was approximately 2.5°C warmer (P = 0.01) compared to the MPB and AFD trailers while stationary at the farm. No differences (P > 0.10) in blood variables were found between trailers. The pHu value of the SM muscle was greater (P = 0.05) for pigs transported in the SPB trailer than in the AFD and MPB trailers. Given the few substantial effects of trailer models on animal welfare and meat quality, these three trailer models can be used indifferently for short-distance transportation in winter conditions in Canada.

Whole-herd risk factors associated with wean-to-finish mortality under the conditions of a Midwestern USA swine production system

Swine wean-to-finish (W2F) mortality is a multifactorial, dynamic process and a key performance indicator of commercial swine production. Although swine producers typically capture the relevant data, analysis of W2F mortality risk factors is often hindered by the fact that, even if data is available, they are typically in different formats, non-uniform, and dispersed among multiple unconnected databases. In this study, an automated framework was created to link multiple data streams to specific cohorts of market animals, including sow farm productivity parameters, sow farm and growing pig health factors, facilities, management factors, and closeout data from a Midwestern USA production system. The final dataset (master-table) contained breeding-to-market data for 1,316 cohorts of pigs marketed between July 2018 and June 2019. Following integration into a master-table, continuous explanatory variables were categorized into quartiles averages, and the W2F mortality was log-transformed, reporting geometric mean mortality of 8.69 % for the study population. Further, univariate analyses were performed to identify individual variables associated with W2F mortality (p < 0.10) for further inclusion in a multivariable model, where model selection was applied. The final multivariable model consisted of 13 risk factors and accounted for 68.2 % (R²) of the variability of the W2F mortality, demonstrating that sow farm health and performance are closely linked to downstream W2F mortality. Higher sow farm productivity was associated with lower subsequent W2F mortality and, conversely, lower sow farm productivity with higher W2F mortality e.g., groups weaned in the highest quartiles for pre-weaning mortality and abortion rate had 13.5 %, and 12.5 %, respectively, which was statistically lower than the lowest quartiles for the same variables (10.5 %, and 10.6 %). Moreover, better sow farm health status was also associated with lower subsequent W2F mortality. A significant difference was detected in W2F mortality between epidemic versus negative groups for porcine reproductive and respiratory syndrome virus (15.4 % vs 8.7 %), and Mycoplasma hyopneumoniae epidemic versus negative groups (13.7 % vs 9.9 %). Overall, this study demonstrated the application of a whole-herd analysis by aggregating information of the pre-weaning phase with the post-weaning phase (breeding-to-market) to identify and measure the major risk factors of W2F mortality.

Identification of trailer heat zones and associated heat stress in weaner pigs transported by road in tropical climates

Heat stress is major welfare concern during transport of pigs in tropical climates, which can also lead to direct production costs. This study evaluated the dynamics of heat zones through the load and their relationship with heat stress of weaner pigs during road transport in a tropical climate. Both environmental (e.g. temperature and relative humidity) and physiological (e.g. respiratory frequency and lactate) measures were recorded from four vehicle journeys (70 km distance, 216 weaner pigs within each trailer load) within Ceará, northeastern Brazil. Geostatistics and fluid dynamics simulation techniques were applied to understand the dynamics of heat zones and ventilation patterns the truckload. Statistics based on canonical discriminant analysis and ANOVA were performed to verify the relationship between heat zones and heat stress in pigs. The results showed that, during transport, the generation of heat zones occurred with different magnitudes along the load (P < 0.05), which was harmonized by the ventilation dynamics. There was a heat core with high energy content, in the front region of the lower deck (LD) of the trailer. In this zone, weaners pigs had higher rectal temperature (+1.8 °C temperature difference), respiratory frequency (LD = 94 ± 1.3 breaths/min; UD = 86 ± 1.3 breaths/min), and blood cortisol concentration (LD = 32.9 ± 0.8 ng/mL; UD = 30.18 ± 0.6 ng/mL) (all P < 0.05). Weaners pigs transported in the upper deck (UD) compartments had the highest skin temperature (LD = 38.13 ± 0.3 °C; UD = 38.9 ± 0.22 °C) and the highest mean values of blood lactate (LD = 65.5 ± 1.11 m/M; UD = 71.60 ± 1.19 m/M) and Creatine kinase (LD = 3891.23 ± 69U/L; UD = 4107.43 ± 62U/L) (P < 0.05). Weaners transported in compartments of the LD of trailer were more susceptible to heat stress, while weaners in the UD compartments were more susceptible to physical stress and muscle exhaustion. These results provide additional evidence of heat zones within trailer compartments and highlight the requirement for the planning of pig transport operations in tropical climates to mitigate risks of heat stress.

Pre-Slaughter Sources of Fresh Meat Quality Variation: The Case of Heavy Pigs Intended for Protected Designation of Origin Products

This study focused on loin quality in Italian heavy pigs intended for the production of PDOs (Protected Designation of Origin) products, and investigated the pre-slaughter factors which negatively affect the quality of fresh meat. Data were collected on 44 shipments (loads) of pigs. Shipments were carried out under commercial conditions. Several pre-slaughter parameters were recorded within the entire process (on-farm, during transport, and at the slaughterhouse). On a subset of pigs (10 animals from every load, N = 440), serum cortisol and creatine kinase were measured and loin samples were analyzed for pH, instrumental color, drip loss, cooking loss, shear force, and sensory quality. Cluster analysis of the instrumentally-assessed meat quality parameters allowed the categorization of the shipments into two clusters: lower quality (LQ) and higher quality (HQ). Our results showed that the factors with significant differences between the two clusters were journey duration, ambient temperature, distance traveled, and irregular behaviors (slipping, falling, and overlapping) at unloading (all greater in LQ, p < 0.05). The pre-slaughter conditions associated with lower loin quality were ambient temperatures above 22 °C, distance traveled above 26 km, travel duration between 38-66 min, more than 5.9% of animals showing irregular behaviors at unloading.

Pork Production with Entire Males: Directions for Control of Boar Taint

Simple Summary

Castration of male piglets has traditionally been carried out to control boar taint, but animal welfare concerns about surgical castration has brought this practice under scrutiny. In addition, castration decreases growth performance and increases the environmental impact of pork production, so alternatives to castration are needed to control boar taint. In this review, we summarize the current knowledge on boar taint metabolism and outline some key areas that require further study. We also describe some opportunities for controlling the boar taint problem and propose that by defining the differences in metabolic processes and the genetic variations that can lead to boar taint in individual pigs, we can design effective custom solutions for boar taint.

Abstract

Boar taint is caused by the accumulation of androstenone and skatole and other indoles in the fat; this is regulated by the balance between synthesis and degradation of these compounds and can be affected by a number of factors, including environment and management practices, sexual maturity, nutrition, and genetics. Boar taint can be controlled by immunocastration, but this practice has not been accepted in some countries. Genetics offers a long-term solution to the boar taint problem via selective breeding or genome editing. A number of short-term strategies to control boar taint have been proposed, but these can have inconsistent effects and there is too much variability between breeds and individuals to implement a blanket solution for boar taint. Therefore, we propose a precision livestock management approach to developing solutions for controlling taint. This involves determining the differences in metabolic processes and the genetic variations that cause boar taint in specific groups of pigs and using this information to design custom treatments based on the cause of boar taint. Genetic, proteomic or metabolomic profiling can then be used to identify and implement effective solutions for boar taint for specific populations of animals.

Changes in oxytocin concentrations in saliva of pigs after a transport and during lairage at slaughterhouse

Oxytocin is associated with reproductive physiology but also with welfare and positive emotions. In this study, oxytocin was measured in saliva samples of 45 pigs that were collected before being transported to the slaughterhouse, at the time of arrival and 4 h after arrival to the slaughterhouse. Two previously validated assays, one that measures free oxytocin and other that measures oxytocin linked to proteins, were used. In addition, cortisol, salivary alpha-amylase (sAA), total esterase activity (TEA), butyrylcholinesterase (BChE) and lactate dehydrogenase (LDH), which are biomarkers associated with stress and pain in pigs, were measured. The results showed a decrease in free and protein-linked oxytocin concentrations at 4 h after transport compared with the time before transport, while cortisol, sAA, TEA, BChE and LDH showed an increase at 4 h after transport compared with the time before transport. Based on these results it can be concluded that the transport and lairage at slaughterhouse in the conditions of this study produce a decrease in oxytocin in the saliva of pigs that could indicate a reduced emotional well-being.

Welfare of pigs during killing for purposes other than slaughter

Pigs at different stages of the production cycle may have to be killed on-farm for purposes other than slaughter (where slaughter is defined as killing for human consumption) either individually (e.g. severely injured pigs) or on a large scale (e.g. unproductive animals or for disease control reasons). This opinion assessed the risks associated with the on-farm killing of pigs and included two phases: 1) handling and moving of pigs and 2) killing methods (including restraint). The killing methods were subdivided into four categories: electrical methods, mechanical methods, gas mixture methods and lethal injection. Four welfare consequences to which pigs can be exposed to during on-farm killing were identified: pain, fear, impeded movement and respiratory distress. Welfare consequences and relevant animal-based measures were described. In total, 28 hazards were associated with the welfare consequences; majority of the hazards (24) are related to Phase 2 (killing). The main hazards are associated with lack of staff skills and training, and poor-designed and constructed facilities. Staff was identified as an origin of all hazards, either due to lack of skills needed to perform appropriate killing or due to fatigue. Corrective measures were identified for 25 hazards. Outcome tables linking hazards, welfare consequences, animal-based measures, hazard origins, preventive and corrective measures were developed and mitigation measures proposed.

Ease of Handling and Physiological Parameters of Stress, Carcasses, and Pork Quality of Pigs Handled in Different Group Sizes

Simple Summary

The effect of different group sizes of pigs (3, 5, and 10 pigs) during handling on physiological parameters, carcasses, and pork quality traits at the farm and slaughterhouse were evaluated in 360 pigs. Ease of handling decreased as the group size increased. Moving pigs in smaller groups improve animal welfare parameters and carcass quality. However, meat quality classifications of the carcasses were not affected by the groups size used in preslaughter handling. Based on the results, moving groups of five pigs seems to be the best strategy to improve animal welfare and carcass quality.

Abstract

The effect of different group sizes of pigs (3, 5, and 10 pigs) during handling on physiological parameters, carcasses, and pork quality traits at the farm and slaughterhouse were evaluated in 360 pigs from five farms (four repetitions or group/treatment/farms). Data was analyzed as a factorial of 3 × 5 (3 treatments × 5 farms) to check effects of treatments by analysis of variance in ANOVA. Ease of handling decreased as the group size increased. However, time taken in handling was not influenced by the group size (p > 0.10). Moving pigs in groups of five animals reduced effects on blood cortisol levels (p < 0.05). Fighting and handling lesions in the carcasses increased for bigger handling groups (p < 0.05). Pigs handled in groups of three and ten animals had a higher pHu and initial temperature in Longissimus thoracis and Semimembranosus (p < 0.05) and lower drip loss in Semimembranosus (p < 0.05). However, meat quality classifications of the carcasses were not affected by treatments. Based on the results, moving groups of five pigs seems to be the best strategy to improve animal welfare, carcasses and pork quality.

Generalized additive mixed model on the analysis of total transport losses of market-weight pigs1

Transportation losses of market-weight pigs are an animal welfare concern, and result in direct economic impact for producers and abattoirs. Such losses are related to multiple factors including pig genetics, human handling, management, and weather conditions. Understanding the factors associated with total transport losses (TTL) is important to the swine industry because it can aid decision-making, and help in the development of transportation strategies to minimize the risk of losses. Hence, the objective of this study was to investigate factors associated with TTL on market-weight pigs in typically field conditions for Midwestern United States using a generalized additive mixed model (GAMM). The final quasi-binomial GAMM included the fixed (main and interactions) effects of abattoir of destination, type of driver, average market weight, distance traveled, wind speed, precipitation, and temperature-humidity index (THI), as well as the random effects of truck companies and the combination of site of origin and period of the year. Results indicate significant associations between TTL and the main effect of all explanatory variables (P < 0.05), except for wind speed and precipitation. Interactions of average market weight × abattoir, and wind speed × precipitation were also significant. A complex nonlinear relationship between TTL and model covariates were observed for distance traveled, THI, and interaction terms. This study showed that TTL of market-weight pigs are caused by a complex system involving multiple interacting factors, which can be potentially managed to mitigate the risk of losses. In addition, the GAMM showed to be a simple and flexible approach to model TTL because it can capture nonlinear relationships, handle non-normal data, and can potentially accommodate data structure.

Risk factors associated with pig pre-slaughtering losses

The incidence of non-ambulatory non-injured (NANI), non-ambulatory injured (NAI) and dead pigs on-arrival at three Brazilian slaughterhouses were evaluated in 37,962 pigs to identify risk factors linked to them, besides carcass bruises and limb fractures. Total pre-slaughtering losses were 1.18%, in which NAI (0.39%) and NANI (0.37%) incidences contributed the most. A positive relation between on farm steeper ramp slope >20° and the incidence of NAI, NANI and dead pigs at unloading was found. Farm size, pigs/pen, enthalpy at loading, transportation time, truck loading order, muscle thickness and carcass weight, were identified as risk factors for pre-slaughtering losses. Loading procedures influenced the occurrence of limb fractures and bruises (which are a welfare issue and should be reduced). Therefore, personal training on pre-slaughter handling is essential to reduce the risk factors to improve animal welfare and avoid losses during the pre-slaughter process.

A Review of Swine Transportation Research on Priority Welfare Issues: A Canadian Perspective

The purpose of this review is to present the best available scientific knowledge on key animal welfare issues during swine transport, such as transport duration and distance, time off feed and water, rest intervals, environmental conditions, loading density, and transport of young animals, based on their impact on stress, injury, fatigue, dehydration, body temperature, mortality, and carcass and meat quality. The review was limited to this set of priority welfare issues which were identified by the National Farm Animal Care Council (NFACC) Scientific Committee to help with the development of the livestock transportation Codes of Practice. This review focuses primarily on research related to the transport of market pigs (100–135 kg) which is a reflection of the current literature available on pig transportation. This information presented here can be used to support other animal welfare codes, guidelines, standards or legislations regulating the welfare of pigs during transport. Based on the available literature, clear conclusions can be drawn on the impact of vehicle design, pre-transport fasting, control of environmental conditions and loading density on the welfare of pigs during transport and on pork quality. However, the effects of journey duration are still unclear and a recommendation on the maximum transport time cannot be provided. Further studies investigating the impact of factors, such as ambient conditions within the transport vehicle, loading density at extreme ambient conditions, travel distances, maximum travel duration, rest/stop duration, and management of pigs during rest stops are required. More specifically, further research in relation to the welfare of market weight, newly weaned and breeding pigs, and cull sows and boars during transport is needed.

Preslaughter handling practices and their effects on animal welfare and pork quality

At all times, prior to slaughter, pigs may experience stress from a range of handling practices, such as fasting, loading and transport, mixing, and interaction with humans. These factors can affect the welfare of pigs and carcass and meat quality, both individually and collectively. Preslaughter stress is both an animal welfare and a meat quality issue. Behavioral and physiological studies have revealed that poor handling practices at the farm, during transport and at the slaughter plant, have an adverse effect on pigs and may result in the loss of profits due to animal losses during transport and in lairage. Also, poor preslaughter handling can also lead to losses in carcass value as a result of reduced yield, the presence of lesions and bacterial contamination, and meat quality defects (e.g., pale, soft, exudative and dark, firm, dry pork). These economic losses can be limited by improving the design of facilities, controlling the environmental conditions, and implementing training programs for the correct animal handling at any stage preslaughter. The objective of this review was to review research findings on the effects of preslaughter practices on ante-mortem behavioral and physiological response in pigs, including muscle metabolism, and to provide recommendations aimed at limiting the impact of preslaughter handling on animal losses and pork quality.