Agricultural Holdings and Slaughterhouses' Impact on Patterns of Pathological Findings Observed during Post-Mortem Meat Inspection

Relationship between animal-based on-farm indicators and meat inspection data in pigs

BACKGROUND

This study aimed to validate slaughterhouse indicators collected during meat inspection as an alternative to on-farm animal welfare indicators. For this purpose, the assessments of twelve on-farm and seven slaughterhouse indicators of 628 pigs from three different farms were combined into three indices, differentiated between on-farm and slaughterhouse: (1) limb health, (2) other organ health, and (3) respiratory health. At first, an assessment at animal-level using agreement parameters was carried out to ascertain whether the same welfare or health issues were identified on-farm and at slaughterhouse, taking the production period (farrowing, rearing and fattening period) and the last weeks before slaughtering into account. Second, the connection of slaughterhouse findings on the individual on-farm health indices was examined using logistic regressions, to determine whether certain welfare issues can be better monitored using slaughterhouse indicators.

RESULTS

Acceptable agreement was determined using the Prevalence-Adjusted Bias-Adjusted Kappa (PABAK) for the farrowing and fattening period, but not for the rearing period. A more detailed analysis of the weeks before slaughter shows that there is still a poor agreement 8 weeks before slaughter and an acceptable agreement 4 weeks before slaughter. This indicated the slaughterhouse indicators pneumonia, pleuritis and pericarditis as possible estimators of fever and deviant behavior on-farm and the slaughterhouse indicators bursitis and joint inflammations as possible estimators of lameness. In the second part of the analysis, the connection of slaughterhouse findings on the individual on-farm health indices was investigated; a significant influence of the farm on the limb and respiratory indices and no significant influence of the slaughterhouse findings could be determined, provided that all weekly assessments during the lifetime of the pigs have been taken into account. However, an influence of the slaughterhouse findings on the respiratory index and on the other organ index could be determined if only the weekly assessments four and eight weeks before slaughter, respectively, were taken into account.

CONCLUSIONS

In general, the possible suitable indicators detected by the PABAK, could replace some health-related indicators but a complete substitution of on-farm welfare assessment is not possible. In addition, the traceability over time must be investigated further.

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.

Can we use meat inspection data for animal health and welfare surveillance?

Ante- and post-mortem inspections at abattoir were originally introduced to provide assurance that animal carcasses were fit for human consumption. However, findings at meat inspection can also represent a valuable source of information for animal health and welfare surveillance. Yet, before making secondary use of meat inspection data, it is important to assess that the same post-mortem findings get registered in a consistent way among official meat inspectors across abattoirs, so that the results are as much independent as possible from the abattoir where the inspection is performed. The most frequent findings at official meat inspections of pigs and beef cattle in Sweden were evaluated by means of variance partitioning to quantify the amount of variation in the probabilities of these findings due to abattoir and farm levels. Seven years of data (2012-2018) from 19 abattoirs were included in the study. The results showed that there was a very low variation between abattoirs for presence of liver parasites and abscesses, moderately low variation for pneumonia and greatest variation for injuries and nonspecific findings (e.g., other lesions). This general pattern of variation was similar for both species and implies that some post-mortem findings are consistently detected and so are a valuable source of epidemiological information for surveillance purposes. However, for those findings associated with higher variation, calibration and training activities of meat inspection staff are necessary to enable correct conclusions about the occurrence of pathological findings and for producers to experience an equivalent likelihood of deduction in payment (independent of abattoir).

Associations of carcass weight and trimming loss with cull dairy cow health observations collected at slaughter

Cull dairy cows account for around 27 percent of total head EU beef and veal production. For the Netherlands specific, even 42 percent (European Commission, 2022). As they are primarily kept to produce milk, red meat production is an additional source of revenue for dairy farmers. Insights in postmortem health observations that are not always visible on the living animal such as heart or liver issues, bruises, adhesions and injuries on the locomotor system, may contain valuable information for farmers to increase revenue and reduce losses in red meat production from cull dairy cows. Our goal was to obtain insights in the association of postmortem health observations with carcass weight and trimming losses. Data of 592,268 slaughter cows were available for analysis and models were built to explain carcass and trimming loss by the postmortem health observations. Carcass weight is lower for younger cows (-3.2 to -84.9 kg), cows with multiple health observations (-7.4 to -34.3 kg) and specific observations for the locomotor system (-16.7 to -22.7 kg), back (-17.9 kg), hindquarter (-21.6 kg) and chest and ribs (-15.5 to -27.6 kg). Total number of health observations (+2.0 to +6.5 kg), observations on the locomotor system (+3.3 to +5.4 kg) and on the chest and ribs (+2.2 to +9.8 kg) were the main predictors for trimming loss. Carcass weight is more affected by systemic health issues and diseases prior to slaughter leading to a negative energy balance and consequently reduced carcass weight. Trimming loss is more a consequence of the focus on meat quality and food safety in the slaughter process. Better understanding of the effect of on-farm management, on health, carcass weight and trimming loss will provide new insights for farmers and veterinarians but will also give them more action perspective to improve dairy farm preventive management and reduce losses at slaughter.

Stochastic partial budget analysis of strategies to reduce the prevalence of lung lesions in finishing pigs at slaughter

Ante- and post-mortem inspections of food-producing animals at slaughter are mandatory activities carried out in many countries to ensure public health, animal health, and meat quality. In finishing pigs, lung lesions are the most frequent defects found in meat inspections. It is possible to implement managerial strategies on-farm to reduce the occurrence and spread of respiratory diseases, but such strategies come with additional costs that could impede implementation. This study assessed the economic impact of two strategies aimed at reducing the prevalence of lung lesions in finishing pigs at slaughter by improving the health conditions of the animals during the production cycle. First, a farrow-to-finish pig farm with 355 sows was modeled based on the current standard practice for finishing pig production in Sweden, using economic data, meat inspection data and biological variables from the literature and expert opinions. A partial budget analysis was then performed in which the baseline farm was compared with two hypothetical strategies aimed at reducing the occurrence and spread of respiratory diseases during pig production: (S1) avoiding mixing of litters after weaning and (S2) keeping purchased pregnant gilts separated from sows during gestation, farrowing and lactation. Both these strategies intended to reduce the occurrence of respiratory disease in finishing pigs at slaughter gave an average gain in annual net income (33,805 SEK in S1 and 173,160 SEK in S2, equal to 3,146€ and 16,113€, respectively, at the time of analysis), indicating that both were economically sustainable under the assumed conditions. The impact analysis of the two strategies revealed that the reduced prevalence of lung lesions when adopting one of the strategies was the most influential factor in net benefit change on the farm. Overall, the results suggest that with the increasing prevalence of lung lesions in Swedish pig production (as also observed worldwide in recent years), adopting an effective strategy to decrease respiratory infections will become more relevant and economically beneficial.

Additional post-mortem inspection procedures and laboratory methods as supplements for visual meat inspection of finishing pigs in Europe—Use and variability

In the EU, a post-mortem inspection of finishing pigs comprises visual inspections of the carcass and offal followed by additional examinations, such as palpation and incision of parts, when needed. Moreover, it can include various laboratory tests. Since European meat inspection is regulated by the EU, one may assume that post-mortem inspection is performed in the same way in the Member States. However, previous studies showed that variations exist. This article shows the results of a survey performed in September 2020 on how visual meat inspection of finishing pigs is applied in Europe. By using a questionnaire, palpations, incisions and other procedures for 10 gross pathological findings and laboratory methods applied by official veterinarians to evaluate the fitness of meat for human consumption were assessed. We received 44 responses from 26 European countries. Most respondents reported that visual meat inspection was a generally applied inspection method. The main reason for not applying visual meat inspection was export requirements. The most important reasons for applying palpations and incisions in addition to visual inspection were findings detected in ante- or post-mortem inspection. There was considerable variation in the use of palpations and incisions, other post-mortem procedures and laboratory tests to assess meat fitness for human consumption. The respondents mentioned some country-specific practices, but we also observed variations within the responding official veterinarians that could not be explained by country of origin or years of work experience. Additional detailed studies on the variation are needed before harmonisation of meat inspection procedures are attempted.

The occurrence of technological damage in slaughtered cattle, pigs, sheep and goats in the Czech Republic

The occurrence of technological damage in cattle, pigs, sheep and goats reared and slaughtered in the Czech Republic was monitored by evaluation and analyzing results of post mortem inspections of official veterinarians from slaughterhouses in the period from 2010 to 2019. We found that technological damage was the most common in pigs, and less common in cattle, sheep and goats. Compared to other species, pigs have statistically the highest occurrence of lung congestion (51.9%–19.3%, in the order: sows, finishing pigs, piglets), insufficient technology processing (0.200%–0.018%, in the order: sows, finishing pigs, piglets), delayed evisceration (0.04%–0.02%, in the order: finishing pigs, sows, piglets), muscle spoilage (0.033%–0.004%, in the order: piglets, finishing pigs, sows) and over-scalding (0.028%–0.013%, in the order: finishing pigs, piglets, sows). Compared to other species, cattle have statistically the highest incidence of different sensory deviations (7.42%–0.33%, in the order: calves, dairy cows, heifers, bulls) and insufficient bleeding (4.4%–2.9%, in the order: bulls, heifers, dairy cows, calves). In all monitored animal species, a similar level of the occurrence of contamination during the carcass processing was recorded (0.37%–0.00%). In sheep and goats, technological damage is generally lower than in pigs and cattle.