The effects of lairage time and handling procedure prior to slaughter on stress and meat quality parameters in pigs

Implications of Lairage and Environmental Enrichment on Behavioral Responses and Skin Lesions in Finishing Pigs in a Slaughterhouse

Different resources, such as environmental enrichment, are being evaluated in order to minimize animal stress and promote better conditions during the life cycle of animals, as consumers are increasingly concerned about animal welfare issues. Lairage represents an important stage in the swine production chain and is directly related to animal welfare. The aim of this study was to evaluate the effect of lairage time in the slaughterhouse and environmental enrichment on the level of skin lesions and behavioral responses in pigs. A total of 648 finishing pigs of both sexes were assessed before and after lairage at the slaughterhouse with a five-point scale (0 = none, to 4 = ≥16 superficial lesions or >10 deep lesions). After lairage (after slaughter), lesions were also classified according to their source (mounting, fighting, and handling). Pigs were distributed into two treatments groups during lairage: with environmental enrichment (EE) on the pen, with hanging metal chains, and with no enrichment (NE). Behavior was monitored during the first four hours of lairage. Proportional odds, mixed linear model for longitudinal data, and non-parametric Wilcoxon signed rank tests were used to analyze the relation between treatments, skin lesions, and behavior. The simple metal chains did not affect skin lesion score or pigs' behavior (p > 0.05), whereas lairage duration influenced standing (SA), sitting (S), lying (L), idleness (I), and drinking water (D) (p < 0.001). The main source of skin lesions was handling, which did not differ between treatments (EE and NE) (p > 0.05). It was observed that the severity of the lesions (highest scores of 3, 4, and 5) increased in the different anatomical regions of the pigs when compared before and after slaughter, with the exception of the frontal area, which was the same (p = 0.7547). Lairage time has a proportional relation with skin lesions, and hanging chains at the slaughterhouse pens was not enough to reduce the number of lesions and to change pig behavior.

Training of transport drivers improves their handling of pigs during loading for transport to slaughter

Pig transport drivers' (TDs') handling actions are of great importance as these drivers handle a large number of finishing pigs during stressful situations. Poor handling techniques can have negative consequences for working conditions, pig welfare and meat quality. We studied the effects of a training intervention on Swedish TDs' attitudes towards pigs and their handling actions during loading for transport to slaughter. Twenty TDs working with commercial pig transportation in Sweden were recruited and completed an attitude questionnaire. Ten of them were observed during one loading of pigs before training, and one or two loadings after training (49-265 pigs per loading), and eight of them completed the attitude questionnaire again 50-160 days after training. The cognitive-behavioural training program ProHand Pigs® was adapted and delivered to the ten TDs during a group session, followed by individual meetings. TDs' handling actions were video recorded and summarised as binary variables per 5-s interval. Factor analysis, principal component analysis and paired t-test were conducted to investigate the effects of the training intervention on TDs' attitudes, and mixed-effects logistic models were used to examine effects on negative and positive handling actions. Training tended to decrease TDs' beliefs that it is important to move pigs quickly (P = 0.095). Training decreased the odds of a 'moderately to strongly negative' action by 55% (P = 0.0013) and increased the odds of a 'positive' action by 97% (P < 0.0001). This study provides valuable insights into the possibilities to improve TDs' handling actions, and implications for pig welfare during slaughter transport. The study supports previous findings that the attitudes and behaviour of handlers can be improved by cognitive-behavioural training. While our previous research has shown reciprocal relationships between TDs' actions and pig behaviour, further research on TDs' attitudes towards handling that underlie the nature of their behaviour when handling pigs is necessary to fine-tune the cognitive-behavioural training program applied in the present study.

Animal welfare at German abattoirs: insights into the occurrence of violations against laws and regulations from official veterinarians and judicial decisions

Introduction

This study investigated the occurrence of various animal welfare violations at German abattoirs by analyzing the results of an anonymous online survey and relevant German court decisions.

Methods

The survey targeted official veterinarians (OVs) and other individuals responsible for enforcing animal welfare laws and regulations at German abattoirs. Participants were asked to report the five most common animal welfare violations in their workplaces during the past 3 years (2019-2021), and whether 22 specific given violations had occurred or not (in the same timeframe). The court decisions were examined to determine how many abattoirs were penalized for a specific animal welfare violation and the details about the number and species of affected animals.

Results

Overall, the violations examined throughout this study fell into one of the following categories: (1) use of prohibited driving aids (e.g., illicit use of electric prods, or hitting/beating animals); (2) inadequate husbandry in lairage; (3) inappropriate handling of animals with special care needs; (4) improper restraint, stunning, and bleeding of animals; and (5) unqualified task execution/inadequate administrative work (e.g., documentation of a violation). The violations analyzed in the scope of this study most frequently fell into categories 1, 2, and 4. Regarding the five violations that survey participants reported to be the most common in the years 2019-2021, 42.6% of responses (N = 277 reported violations) fell into category 4, followed closely by category 1 with 37.9%. Of the 22 violations surveyed in the second part of the survey, those reported by 50.0% or more participants were concentrated in categories 1, 2, and 4. Regarding the 16 relevant court rulings spanning from 2015 to 2022, the most frequently documented instances of misconduct primarily fell into category 1.

Discussion

The collected data suggest that there may be need for improvements regarding compliance with animal welfare legislation, especially concerning categories 1, 2, and 4. The authors suggest OVs to consider these findings when conducting monitoring activities at abattoirs and in the training and education of abattoir personnel.

Electro-thermal injuries in ruminants caused by electrical equipment during pre-slaughter operations: Forensic case reports from an animal welfare science perspective

The use of electrical equipment for herding and moving livestock (electric batons) or for stunning animals before slaughter (electric stunners) is widespread in the livestock and meat industries worldwide. The use of these equipment is restricted to specific procedures and/or exceptional circumstances that justify their rational use. However, these restrictions can be underestimated or disregarded due to ignorance, inexperience, incompetence or irresponsibility on the part of users, resulting in pain and suffering to the animals and, in some cases, electro-thermal injury. This report presents four forensic cases of electro-thermal injuries identified during post-mortem animal welfare assessments in slaughterhouses in Colombia, Mexico and Spain. Electro-thermal injuries caused by contact (accidental or intentional) of equipment electrodes with skin and subcutaneous tissue are presented. Although our cases are isolated events detected over a 5-year period, they provide a useful visual guide for technicians and veterinarians interested in the differential diagnosis between bruises and electro-thermal injuries. The differentiation of the equipment causing the injuries allows the identification and control of critical points for animal welfare along the pre-slaughter logistic chain and the elimination of inappropriate animal handling practices.

The impact of overnight lairage on meat quality and storage stability of pork loin

Lairage, a part of the animal welfare practices, has been known to mitigate pre-slaughter stress in animals. However, research investigating the relationship between lairage and pork meat quality remains scarce. In this study, we conducted a comparative analysis of the physicochemical quality and storage stability of pork from pigs subjected to immediate slaughter (CON) and those provided with a 24 h lairage before slaughter (LRG) over a 7-day storage period. The loins from 20 castrated pigs in each group, respectively, were collected at 1, 3, 5, and 7 days and used for analysis of meat quality and storage stability, including pH, meat color, moisture, water holding capacity, drip loss, cooking loss, shear force, fatty acid composition, lipid oxidation, antioxidant activity, and electrical resistance. Overall, there were no significant differences in physicochemical meat quality parameters between CON and LRG groups. Similarly, no differences were observed in the storage stability of pork including 2-thiobarbituric acid reactive substances, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and electrical resistance. However, the proportion of unsaturated fatty acids was significantly higher in LRG compared to CON. In conclusion, 24 h lairage for castrated pigs had limited impact on meat quality and storage stability but led to an increase in the unsaturated fatty acid proportion.

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.

Measures and Penalties for Animal Welfare Violations at German Abattoirs: A Compilation of Current Recommendations and Practices

Protecting animal welfare during preslaughter handling and slaughter is an important ethical concern with growing importance to consumers. However, animal welfare violations in abattoirs remain a serious problem, and the enforcement of relevant laws and regulations is often inadequate. This study investigated and compiled the measures and penalties which official veterinarians (OVs) consider appropriate for different animal welfare violations at German abattoirs, including ranges for fines. Additionally, information regarding which measures were taken in past cases, including past procedural outcomes (e.g., judicial decisions and regulatory animal welfare orders in Germany), were gathered and summarised. The aim is to provide insights into the status quo, so that flaws in law enforcement (e.g., imposing low penalties or not filing a criminal complaint when necessary) can be identified in a future study. To achieve this, the following five steps were utilised: acquiring relevant judicial decisions; conducting an anonymous online survey among German OVs; conducting semi-structured interviews with OVs; conducting a virtual colloquium with OVs; and consulting lawyers. Measures and penalties for violations of 40 relevant and frequent different provisions of the German Ordinance on the Protection of Animals in connection with Slaughter or Killing (TierSchlV), in conjunction with the Regulation (EC) No 1099/2009 and the German Animal Welfare Act, were gathered. The findings were compiled into a list of measures and penalties, which contains a separate table for all 40 violations, entailing an overview of the following information: citation(s) of legal/regulatory requirements to protect animals at the time of killing/slaughter; citation(s) of relevant regulatory and criminal penalties; special measures/penalties considered appropriate for the first and repeated offence by OVs; and information on penalties listed in judicial decisions of past similar cases. This initiative is a step towards achieving a reduction of animal welfare violations at German abattoirs.

Body Weight Estimation for Pigs Based on 3D Hybrid Filter and Convolutional Neural Network

The measurement of pig weight holds significant importance for producers as it plays a crucial role in managing pig growth, health, and marketing, thereby facilitating informed decisions regarding scientific feeding practices. On one hand, the conventional manual weighing approach is characterized by inefficiency and time consumption. On the other hand, it has the potential to induce heightened stress levels in pigs. This research introduces a hybrid 3D point cloud denoising approach for precise pig weight estimation. By integrating statistical filtering and DBSCAN clustering techniques, we mitigate weight estimation bias and overcome limitations in feature extraction. The convex hull technique refines the dataset to the pig's back, while voxel down-sampling enhances real-time efficiency. Our model integrates pig back parameters with a convolutional neural network (CNN) for accurate weight estimation. Experimental analysis indicates that the mean absolute error (MAE), mean absolute percent error (MAPE), and root mean square error (RMSE) of the weight estimation model proposed in this research are 12.45 kg, 5.36%, and 12.91 kg, respectively. In contrast to the currently available weight estimation methods based on 2D and 3D techniques, the suggested approach offers the advantages of simplified equipment configuration and reduced data processing complexity. These benefits are achieved without compromising the accuracy of weight estimation. Consequently, the proposed method presents an effective monitoring solution for precise pig feeding management, leading to reduced human resource losses and improved welfare in pig breeding.

Association between Enzootic Pneumonia-like Lung Lesions and Carcass Quality and Meat pH Value in Slaughter Pigs

Although the prevalence of respiratory diseases in slaughter pigs ranges from 19% to 74% and continues to be an important concern for swine herds worldwide, only a few studies have investigated the relationship between respiratory disease and pork quality. The general aim of this study was to investigate associations between the prevalence and severity of enzootic pneumonia-like lesions in Polish slaughter pigs on different carcass and meat-quality characteristics at the animal and herd levels. The average prevalence of bronchopneumonic lungs with different degrees of lesions was 94.57%. The majority of lesions indicated the acute stage of enzootic pneumonia. Our results indicate a statistically significant interaction between the mean weight of carcasses depending on the extent of the lesions (p = 0.04) at the animal level. The correlation between meatiness and severity of lung lesions was r = -0.25 (p = 0.00). The correlation between the extent of lung lesions and pH₄₅ value was r = -0.17 (p = 0.005) on the animal level and r = -0.63 (p = 0.017) at the herd level. This implies that lung lesions in slaughter pigs negatively influence not only animal health and welfare, but also carcass quality.

Impact of Procedures and Human-Animal Interactions during Transport and Slaughter on Animal Welfare of Pigs: A Systematic Literature Review

Animal welfare is a high social and political priority and is enshrined in European and national legislation. This systematic literature review (funded by the German Ministry of Food and Agriculture; grant no. 2817806A18) was conducted to find animal and management-based indicators that could be influenced by changes in pig handling and management procedures on the day of slaughter and, therefore, will directly result in improved animal welfare. For this systematic literature review, following the PRISMA guidelines, we conducted a structured literature search using the databases PubMed^®, Web of Science^TM, and LIVIVO with set search terms and their combinations in German and English. Only peer-reviewed original articles from European countries from 2009 until 2022 that dealt with welfare during transport and/or slaughter of fattening pigs and offered potential measurable indicators on the basis of the animal or management, and either directly or indirectly recommended handling practices were included. We used the literature management system EndNote^TM, and after duplicate removal, a total of 1099 records were found for further analysis. After analysis and discussion in the review team, which consisted of three experts in total, 105 articles underwent full-text screening. Finally, 39 articles were included in the results for this systematic literature review. According to this systematic literature review, the following procedures have a positive impact on the animal welfare of pigs on the day of slaughter. Calm-rather than rough-handling of pigs was the most influential factor. This can be achieved by using animal-friendly driving aids. Loud noise should be avoided in general or reduced as far as possible. Transport time is not always influenceable, but shorter transport duration with stocking density as stated by the European regulations as a maximum will reduce stress in pigs. Our review showed that there are differing scientific results about lairage duration, although this should be set in relation to prior stress and transport time. Knowledge of good stunning parameters, such as gas concentration, exposure time to the gas, recommended amperage, and current flow duration is essential. If electrical stunning is performed, the correct attachment of electrodes is crucial. The control of stunning effectiveness is extremely important to avoid suffering and pain, with the proviso that it is assessed on the basis of multiple parameters. The corneal reflex, regular gasping, and the up-righting reflex could be assessed together. Certificates of competence and continuing educational programmes for the personnel form the basis of animal-friendly handling and a stressless slaughter routine. It can be assumed that the results of this systematic literature review reflect the state of current research of pig welfare during transport and slaughter in the European Union, even though it must be assumed that not all relevant points were covered by the review, which can be seen as a limitation at the same time because important non-European or older publications could not be included.

Biosecurity and Lairage Time versus Pork Meat Quality Traits in a Farm-Abattoir Continuum

The modern pig production chain is increasingly focused on biosecurity, quality, and safety of meat and is associated with many challenges impacting world meat markets, such as animal disease outbreaks and sanitary restrictions, trade regulations and quality requirements. To overcome such challenges and assure more consistent pork meat quality (and safety), there is a need to develop an effective and reliable monitoring system in a farm-abattoir continuum that can be based on selected biomarkers. This study assessed interrelations of selected stress and inflammation biomarkers (acute phase proteins (APP)) between farm biosecurity score versus pork meat quality traits after two different lairage periods. Briefly, the maximum recorded levels of stress hormones (436.2 and 241.2 ng/mL, for cortisol and Chromogranin A (CgA), respectively) and APP (389.4 and 400.9 μg/mL, Pig Major Acute Proteins (MAP) and Haptoglobin (Hp), respectively) at four commercial farms were within the recommended threshold values. Cortisol and APP were negatively correlated to the internal and total biosecurity scores of farms. The increase of level of both sets of biomarkers was found at bleeding (after transportation and lairage period), but with lower values after long (18-20 h) versus short (1-3 h) lairage lay-over time. In general, negative correlation was confirmed between stress and inflammation biomarkers and carcass/meat quality traits. The farm total biosecurity level significantly affected chilling yield, meat temperature, and a* value. Pig-MAP emerged as a good biomarker with a promising potential for assessment and anticipation of broad aspects in the pork meat chain. It can be used for detection of failures in the pig production system and might be incorporated in certification programs for the pork meat industry.

Risk Factors for Chronic Stress in Sows Housed in Groups, and Associated Risks of Prenatal Stress in Their Offspring

Chronic stress has a detrimental effect on sow welfare and productivity, as well as on the welfare and resilience of their piglets, mediated prenatally. Despite this, the specific risk factors for chronic stress in pregnant sows are understudied. Group-housed pregnant sows continuously face numerous challenges associated with aspects of the physical (group type and size, flooring, feeding system) and social (stocking density, mixing strategy) environment. There are many well-known potent stressors for pigs that likely contribute to chronic, physiological stress, including overcrowding, hot temperatures, feed restriction, inability to forage, uncomfortable floors, and poor handling. Some of these stressors also contribute to the development of production diseases such as lameness, which in turn are also likely causes of chronic stress because of the associated pain and difficulty accessing resources. The aim of this review is to discuss potential risk factors for chronic stress in pregnant sows such as space allowance, group size and type (stable/dynamic), feeding level, lameness, pen design, feed system, enrichment and rooting material, floor type, the quality of stockmanship, environmental conditions, and individual sow factors. The mechanisms of action of both chronic and prenatal stress, as well as the effects of the latter on offspring are also discussed. Gaps in existing research and recommendations for future work are outlined.

Carcass Lesion Severity and Pre-Slaughter Conditions in Heavy Pigs: A Prospective Study at a Commercial Abattoir in Northern Italy

Pre-slaughter conditions and their effects on carcass quality have been largely addressed for pigs of 90–100 kg live weight, while few studies consider the effects of pre-slaughter conditions on the quality of the carcasses obtained from heavy pigs intended for Protected Designation of Origin (PDO) production. A total of 1680 heavy pigs were transported in 72 batches from a farm to a commercial abattoir on 16 different days, avoiding mixing unfamiliar animals. Slaughterhouse conditions, animal behaviors, and human–animal interactions were annotated at unloading and during the race toward the stunning cage. Carcass lesions on the rear, middle, and shoulder parts of the carcasses were scored. The prevalence of carcasses with severe lesions was 6.92%, 11.87%, and 6.83%, for the rear, middle, and shoulder parts, respectively. Among the pre-slaughter events, waiting before unloading and improper handling practices at the abattoir were the major factors affecting carcass lesion severity. Lairage pen space allowance was also found to affect severe rear and shoulder lesions, and the batches that were transported in the trailer had an increased prevalence of severe shoulder lesions. Our results suggest waiting time before unloading should be shortened as much as possible, and educational programs to train operators for more careful management of animals in the abattoir are greatly required to avoid improper animal handling practices.

Physiological and electroencephalogram responses in goats subjected to pre-and during slaughter stress

A comprehensive stress assessment is vital in understanding the impact of the pre-slaughter procedure on animal welfare. The transportation and handling process was commonly reported to cause stress in animals. This research utilises electroencephalography (EEG) as an alternative stress indicator to non-painful acute stress measurement. EEG has been proved to be instantaneous and sensitive with specific results. Therefore, this study was aimed to determine the stress level of goats subjected to two different transportation duration and the effect of lairage based on their EEG activities and blood parameters changes. Eighteen adult male goats were divided into two transportation stress groups based on the transport duration: the two-hour (TS2) and six-hour (TS6) groups. Then, each group was then again divided into three smaller groups according to the lairage duration, which was three-hour (L3), six-hour (L6), and overnight (L12) groups. Blood was sampled before transport, after transport, and during slaughter while EEG was recorded before transport, after transport, after lairage, and during slaughter. Results revealed that there was a significant decrease in beta wave activity compared to baseline in TS2 goats (P < 0.05) after transportation, whereas no significant difference was detected in the TS6 goats. At the same time, goats from the TS2 group showed increase in creatine kinase (CK) and lactate dehydrogenase (LDH) compared to that in TS6 goats. Together with the observed cortisol concentration, these findings showed that the TS6 goats were fully adapted to the transportation stress while the TS2 goats were still under stress. As for the lairage duration, it was observed that the TS2L3 goats showed lower EEG activities than the values obtained after two-hour transportation, while lower EEG activities were found from the TS6L6 goats after six-hour transportation. Therefore, it can be concluded that three-hour lairage was adequate to lower the impact of two hours transportation stress, whereas six-hour lairage was required to reduce the impact of six hours transportation stress. Finally, it was also found that the TS6L3, TS6L6, and TS6L12 groups took a long time to die after slaughter than the TS2L3, TS2L6, and TS2L12 goats based on the time their EEG activity reached isoelectric.

The effects of feeding finishing pigs of two genders with a high fiber and high fat diet on muscle glycolytic potential at slaughter and meat quality

A total of 160 pigs, in groups of 8 pigs of mixed genders, were fed four finishing feeding strategies with the aim to reduce muscle glycolytic potential and improve meat quality. Pigs were fed a control diet (C; fat = 5.0%, ADF = 3.0%, NDF = 8.8%), a high-fat and high-fiber diet (HFF; fat = 11.2%, ADF = 9.1%, NDF = 19.5%), a blend of 50-50% C and HFF diets (fat = 8.2%, ADF = 6.7%, NDF = 14.2%) or the C diet and transferred to the HFF diet after a diet transition. Dietary treatments alone or in interaction with gender had no effect on pig growth performance, carcass quality traits, Longissimus and Semimembranosus muscle glycolytic potential and meat quality (P > 0.10). The inefficiency of the dietary treatments applied in this study may be due to the low ratio between fat and digestible carbohydrate in the diets combined with the mild pre-slaughter stress conditions pigs were exposed to.

Abattoir-Based Measures to Assess Swine Welfare: Analysis of the Methods Adopted in European Slaughterhouses

Simple Summary

The welfare of pigs is a major concern among some consumers and pig producers. This concern has driven welfare specialists into the validation of methods and protocols that can be used to evaluate the welfare status of pigs on farms. These protocols require the use of animal-, management and resource-based measures, although data collected from the animals are generally considered more useful. However, due to some limitations, these schemes are not always applicable; therefore, the use of simplified schemes involving the collection of data from pigs at the slaughterhouse has been advocated. Methods and scoring schemes recently described and used in studies performed in European slaughterhouses to determine pig welfare and health are reviewed in the present manuscript. A focus on the scoring schemes for lesions of the body and viscera during post-mortem activities at the abattoir is provided. These methods can be used to benchmark a welfare scheme suitable for all European competent authorities and professionals working in the context of pig welfare.

Abstract

The assessment of swine welfare requires feasible, reliable, and reasonable indicators. On-farm evaluation of pig welfare can provide valuable information to veterinarians and farmers. However, such protocols can result expensive and time-consuming. With this regard, an interest in the appraisal of swine welfare at abattoir has grown over the recent years. In particular, the use of certain lesions collected directly from slaughtered animals to determine the welfare status of pigs has been evaluated by several authors. In the present review, the different methods developed to score lesions collected directly from the body and the viscera of animals slaughtered in European abattoirs (“abattoir-based measures”) are presented. The text specifically focuses on the methods currently available in the literature for the scoring of body, pluck and gastric lesions during post-mortem activities. Moreover, the strengths and weaknesses of abattoir-based measures schemes are discussed. To conclude, the future perspectives of the assessment of pig welfare at the slaughterhouse are described, appealing for a benchmarking system that can be systematically used by veterinarians and other professional figures involved in the process.

Fasting Finisher Pigs before Slaughter Influences Pork Safety, Pork Quality and Animal Welfare

The final phase in pork production is the transport of finisher pigs to the slaughterhouse. Fasting is one of the parameters that influence the stress coping ability of the pigs during transport and lairage. When implemented correctly with attention to the local factors, pre-slaughter fasting can improve animal welfare, pathogen risk and carcass hygiene. The length of pre-slaughter feed withdrawal time is important to the success of the production practice. In practice, a fasting time before slaughter between 12 and 18 h enhances pork safety, pork quality, and animal welfare. This means that communication between producer and slaughterhouse is essential when planning the fasting and lairage times to avoid carcass and technological pork quality problems (such as pale, soft, and exudative (PSE) meat or dark, firm and dry (DFD) meat).

Acetylation and Phosphorylation of Proteins Affect Energy Metabolism and Pork Quality

Preslaughter handling has been shown to significantly affect meat quality, but the mechanisms are not fully understood. In this study, we investigated protein phosphorylation and acetylation in pig muscles at early postmortem time and their associations with meat quality attributes. Thirty pigs were randomly assigned to traditional (TH, n = 15) or mild handling (MH, n = 15). Compared with TH, MH reduced the incidence of pale, soft, and exudative (PSE) or dark, firm, and dry (DFD) pork. MH induced 65 and 20 peptides that match with 39 and 12 proteins to be more highly phosphorylated and acetylated, respectively. Creatine kinase, β-enolase, α-1,4-glucan phosphorylase, tropomyosin, and myosin heavy chain isoforms 1, 4, and 7 were found to be simultaneously phosphorylated and acetylated, which may involve glycolysis, tight junctions, and muscle contraction. The phosphorylation and acetylation levels of differential proteins showed significant correlations with meat quality traits. These findings indicate that preslaughter MH can improve meat quality by regulating protein phosphorylation and acetylation involving energy metabolism in muscle.

Welfare of pigs at slaughter

The killing of pigs for human consumption (slaughtering) can take place in a slaughterhouse or on farm. The processes of slaughtering that were assessed for welfare, from the arrival of pigs until their death, were grouped into three main phases: pre-stunning (including arrival, unloading from the truck, lairage, handling and moving of pigs); stunning (including restraint); and bleeding. Stunning methods were grouped into three categories: electrical, controlled atmosphere and mechanical. Twelve welfare consequences the pigs can be exposed to during slaughter were identified: heat stress, cold stress, fatigue, prolonged thirst, prolonged hunger, impeded movement, restriction of movements, resting problem, negative social behaviour, pain, fear and respiratory distress. Welfare consequences and relevant animal-based measures were described. In total, 30 welfare hazards that could occur during slaughter were identified and characterised, most of them related to stunning and bleeding. Staff were identified as the origin of 29 hazards, which were attributed to the lack of appropriate skill sets needed to perform tasks or to fatigue. Corrective and preventive measures for these hazards were assessed: measures to correct hazards were identified, and management was shown to have a crucial role in prevention. Outcome tables linking hazards, welfare consequences, animal-based measures, origins and preventive and corrective measures were developed for each process. Mitigation measures to minimise welfare consequences are proposed.

Application of extended feed withdrawal time preslaughter and its effects on animal welfare and carcass and meat quality of enriched-housed pigs

A total of 144 barrows were distributed into four treatment groups. One group was housed conventionally and fasted for 16 h preslaughter, while the other three groups were housed in enriched conditions (straw-bedding and low density) and fasted for 16, 24 and 32 h preslaughter. When compared with conventionally-housed pigs, enriched-housed pigs were heavier (P < .05) and fatter (P < .01), but easier to handle at loading (P < .05) and produced less exudative pork (P < .05) possibly resulting from a lower post-mortem muscle glycolytic potential (P = .10). Extending fasting time up to 32 h reduced dressing yield (P < .001) and increased skin lesion scores (P < .01), but did not result in any clear or major effect on muscle metabolism and meat quality. In conclusion, given the beneficial effects of enriched housing conditions on stress response and pork quality, the application of an extended fasting time (32h) preslaughter is not required for this production.

Meat quality in the Danish pig population anno 2018

The level of meat quality was assessed in a random sample of the Danish pig population. No PSE was found in m. semimembranosus, and, depending on the definition of PSE, no pigs or only 2% of the pigs were categorised as having PSE in the M. longissimus lumborum. The ultimate pH had a low variability in M. longissimus lumborum (2.5%), m. semimembranosus (2.7%) and m. semispinalis capitis (4.9%) indicating that the quality of the meat with respect to these attributes was uniform. The drip loss was as high as 7%, although on average (2.23%) its value was lower than that previously found in a sample of the Danish pig population. A gender difference between entire male pigs and castrates was seen for drip loss and tenderness (shear force), with loins from castrates being less exudative (P < .001) and more tender (P < .01) than those from entire males. In conclusion, the Danish pig population showed a uniform meat quality.

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.

Stress Effects on Meat Quality: A Mechanistic Perspective

Stress inevitably occurs from the farm to abattoir in modern livestock husbandry. The effects of stress on the behavioral and physiological status and ultimate meat quality have been well documented. However, reports on the mechanism of stress effects on physiological and biochemical changes and their consequent effects on meat quality attributes have been somewhat disjointed and limited. Furthermore, the causes of variability in meat quality traits among different animal species, muscle fibers within an animal, and even positions within a piece of meat in response to stress are still not entirely clear. This review 1st summarizes the primary stress factors, including heat stress, preslaughter handling stress, oxidative stress, and other stress factors affecting animal welfare; carcass quality; and eating quality. This review further delineates potential stress-induced pathways or mediators, including AMP-activated protein kinase-mediated energy metabolism, crosstalk among calcium signaling pathways and reactive oxygen species, protein modification, apoptosis, calpain and cathepsin proteolytic systems, and heat shock proteins that exert effects that cause biochemical changes during the early postmortem period and affect the subsequent meat quality. To obtain meat of high quality, further studies are needed to unravel the intricate mechanisms involving the aforementioned signaling pathways or mediators and their crosstalk.

Changes in alpha-amylase activity, concentration and isoforms in pigs after an experimental acute stress model: an exploratory study

BACKGROUND

Salivary alpha-amylase (sAA) is considered a non-invasive biomarker of acute stress that can be evaluated by changes in activity and concentration, and also by changes in its isoforms, although this last way of evaluation has never been used in veterinary medicine. This research evaluated the changes of sAA by three different ways in which sAA can be evaluated in an experimental acute stress model in six pigs based in a technique of temporarily restraining. These ways of evaluation were 1) activity by a spectrophotometric assay, 2) concentration by a fluorometric assay, and 3) isoforms of the enzyme by a Western blot.

RESULTS

Although salivary cortisol significantly increased due to the stimulus of stress and all the pigs manifested signs of stress by high-pitched vocalization, sAA activity showed an increase of different degree in the six pigs after the stress stimulus, while sAA concentration showed decreases in four of the six pigs. sAA activity did not correlate with sAA concentration or salivary cortisol, and a low correlation was observed between sAA concentration and salivary cortisol (r = 0.48, p = 0.003). The inter-individual variability was higher in sAA activity than in sAA concentration and salivary cortisol. Finally, three possible isoforms of sAA at 154-160 kDa, 65-66 kDa and 59-60 kDa were observed that showed different dynamics after the stress induction.

CONCLUSIONS

Although this pilot study's results should be taken with caution due to the low sample size, it reveals a different behavior between sAA activity and concentration in pig after an acute stressful stimulus leading to evident external signs of stress by high-pitched vocalization, and opens a new field for the evaluation of possible selected isoforms of sAA as potential biomarkers of stress.

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.

Characterization of variability in pork carcass composition and primal quality,

The objective was to characterize the factors and production practices that contribute to variation in pork composition and quality. It is possible the variation in pork quality traits, such as color, marbling, and tenderness, contributes to reduced customer confidence in the predictability of finished product quality and, therefore, pork products becoming less competitive for consumer dollars. Pigs raised in 8 different barns representing 2 seasons (hot and cold) and 2 production focuses (lean and quality) were used in this study. Pigs were marketed in 3 groups from each barn and marketing procedures followed commercial marketing procedures. Data were collected on a total of 7,684 pigs. The mivque0 option of the VARCOMP procedure in SAS was used to evaluate the proportion of variation each independent variable (season, production focus, marketing group, sex, and random variation) contributed to total variance. Random variation including inherent biological differences, as well as factors not controlled in this study, contributed the greatest proportion to total variation for each carcass composition and quality trait. Pig and other factors contributed to 93.5% of the variation in HCW, and marketing group, sex, season, and production focus accounted for 4.1, 1.4, 0.8, and 0.3%, respectively. Variation in percent carcass lean was attributed to production focus (36.4%), sex (15.8%), and season (10.2%). Pig and other factors contributed the greatest percentage of total variation (39.4%). Loin weight variation was attributed to production focus (21.4%), sex (5.4%), season (2.7%), marketing group (1.8%), and pig (68.7%). Belly weight variation was attributed to pig (88.9%), sex (4.1%), marketing group (3.8%), production focus (3.0%), and season (0.1%). Variation in ham weight was attributed to pig and other factors (93.9%), marketing group (2.8%), production focus (2.2%), and season (1.1%). Ultimate pH variation was attributed to pig (88.5%), season (6.2%), production focus (2.4%), marketing group (2.2%), and sex (0.7%). Aside from pig (71.9%), production focus (14.0%) was the next largest contributor to variation in iodine value followed by sex (13.2%) and marketing group (0.9%). Variation in carcass quality and composition could be accounted for, but the greatest percentage of variation was due to factors not accounted for in normal marketing practices.

Total esterase measurement in saliva of pigs: Validation of an automated assay, characterization and changes in stress and disease conditions

An automated spectrophotometric method for total esterase activity (TEA) measurement in porcine saliva has been developed and validated, using 4-nitrophenyl acetate (4-NA) as substrate. The method was precise and accurate, with low limit of detection, and was able to measure samples with TEA activities up to 400IU/L without any dilution. In addition, the different enzymes contributing to TEA were characterized, being identified carbonic anhydrase VI (CA-VI), lipase, cholinesterase (ChE) and cholesterol esterase (CEL). TEA significantly increased (1.49-fold, P<0.01) in healthy pigs just after applying an acute stress stimulus consisting of nasal restraint, being lipase and cholinesterase the main responsible of this increase. TEA was significantly increased (1.83-fold, P<0.001) in a group of pigs with lameness; in this case, in addition to lipase and ChE, CA-VI also increased. The results found in this report indicate that TEA can be easily measured in porcine saliva with an accurate and highly reproducible automated method. Salivary TEA is mainly due to the activity of four enzymes: CA-VI, lipase, ChE and CEL, and these enzymes can change in a different way in situations of stress or disease.

Activities of some stress enzymes as indicators of slaughter cattle welfare and their relationship with physico-chemical characteristics of beef

The study determined the activities of creatine kinase (CK) and lactate dehydrogenase (LDH) in transported cattle as indicators of welfare and how they relate to beef quality. A total of 219 (n=219) (85 Beefmaster, 48 Charolaise, 32 Holstein-Friesian and 54 nondescript) cattle brought to the abattoir for slaughter were used in the study. Disposable vacutainer tubes with anticoagulant (ethylenediaminetetraacetic acid) were used to collect 4 ml of blood samples to determine the activities of CK and LDH. The measurements of pHu and colour coordinates (L*, a* and b*) were carried out at 48 h after slaughter on the representative samples of muscularis longissimuss thoracis et. lumborum (LTL). Longer distance travelled by cattle had a significant effect (P3000 to 5000) and those that travelled for 1263 km had lower CK activities (1000). The activities of LDH were observed in cattle that travelled for 366 and 1012 km (7000) and for those that travelled for 877 and 922 km (6000). Results of the principal component analysis showed that the first three principal components (PCs) explained about 53% of the total variability. The first PC was correlated with meat quality attributes (pHu, Tm, a* and b* values). The activities of CK and LDH were related and useful to define the second PC. However, CK and LDH were not related to beef quality. Therefore, CK and LDH can be used as indicators of welfare in slaughter cattle but cannot be used to predict the quality of meat.

Transport Fitness of Cull Sows and Boars: A Comparison of Different Guidelines on Fitness for Transport

n/a.

Pork Quality Traits According to Postmortem pH and Temperature in Berkshire

This study was performed to investigate the role of pH and temperature postmortem, and to demonstrate the importance of these factors in determining meat quality. Postmortem pH 45min (pH at 45 min postmortem or initial pH) via analysis of Pearson's correlation showed high positive correlation with pH change pH c24 (pH change from pH 45min to pH 24h postmortem). However, postmortem pH after 24 h (pH 24h or ultimate pH) had a high negative correlation with pH change, pH c24 , CIE L*, and protein content. Initial temperature postmortem (T 1h ) was positively associated with a change in temperature from 45 min to 24 h postmortem (T c24 ) and cooking loss, but negatively correlated with water holding capacity. Temperature at 24 h postmortem (T 24h ) was negatively associated with T c24 . Collectively, these results indicate that higher initial pH was associated with higher pH c24 , T 1h , and T c24 . However, higher initial pH was associated with a reduction in carcass weight, backfat thickness, CIE a* and b*, water holding capacity, collagen and fat content, drip loss, and cooking loss as well as decreased shear force. In contrast, CIE a* and b*, drip loss, cooking loss, and shear force in higher ultimate pH was showed by a similar pattern to higher initial pH, whereas pH c24 , carcass weight, backfat thickness, water holding capacity, fat content, moisture content, protein content, T 1h , T 24h , and T c24 were exhibited by completely differential patterns (p<0.05). Therefore, we suggest that initial pH, ultimate pH, and temperatures postmortem are important factors in determining the meat quality of pork.

ENRIQUECIMENTO AMBIENTAL E COMPORTAMENTO DE SUÍNOS: REVISÃO

É cada vez maior a preocupação da comunidade científica e do mercado consumidor em relação aos métodos que os animais são produzidos. As novas exigências do mercado externo, em relação à qualidade ética dos produtos disponibilizados para o consumo, requerem novas técnicas direcionadas ao bem-estar animal. Na suinocultura industrial, os animais, geralmente, vivem confinados em todas as fases da vida. Portanto, estudos vêm sendo realizados para minimizar os efeitos do estresse gerados pelos monótonos ambientes de confinamento. O uso de objetos de enriquecimento ambiental pode ser uma alternativa viável de adaptação ao sistema de produção de suínos presente no Brasil. Contudo, sua eficácia ainda é limitada devido à rápida habituação dos suínos aos objetos disponibilizados. O objetivo deste artigo é revisar alternativas de enriquecimento ambiental usadas na suinocultura.