From Field to Fork: Can Respiratory Diseases Affect the Quality of Pork?

Porcine respiratory disease complex (PRDC) significantly impacts the global pig industry, particularly during the growing and finishing phases. This multifaceted syndrome is characterized by a combination of pathogens and environmental stressors affecting the respiratory system. It leads to substantial economic losses through decreased growth rates, increased feed conversion ratios, higher mortality, and elevated costs for veterinary treatments and management^(1,2).

Paulina Przyborowska, Renata Lewko-Wojtowicz, Dawid Tobolski

While the negative impact of these conditions on finishing pigs is well-documented, most studies quantify losses in terms of live animal production rather than meat quality or carcass traits. To date, few studies have investigated the relationship between respiratory diseases and pork quality^(3–5). Those that do often employ statistical models to determine the effect of lesions, commonly found during abattoir inspections, on carcass weight and meat quality.

There is limited literature that comprehensively reviews the impact of lung lesions on pig production from a meat processing perspective. Given the complexity of meat as a product, it is essential to highlight that assessing lung lesions can provide insights into livestock welfare and production efficiency. Additionally, these assessments contribute to understanding meat quality and slaughter yield (Figure 1).

Figure 1. Assessment of lung changes as indicators of livestock welfare and production efficiency.

This article reviews the effects of cranio-ventral pulmonary consolidation (CVPC) and pleurisy on the carcass characteristics of finishing pigs. Such an approach allows for a rigorous assessment of how respiratory conditions influence carcass and meat quality, crucial factors for meat processing (Table 1).

Table 1. The descriptive data of investigated mean values for carcass and meat traits⁽⁶⁾.

Batches with no (-), mild (+), moderate (++), and severe (+++) CVPC lesions; (m) mean carcass weight; (SD) standard deviation, (V) variation; (min.- max.) minimum to maximum value; (pH45) mean pH value measured 45 minutes postmortem; carcass meatiness- lean meat content.

Data obtained based on investigating a total of 3,060 lungs from slaughtered pigs from 102 different swine batches. Table summarize potential alterations in certain traits depending on the severity of lung lesions.

A critical finding for pig producers is that several authors have noted a significant negative association between the extent of pulmonary lesions and the percentage of lean meat content, which directly affects economic returns by reducing meat yield and quality^(3,4,6). This results in a downgrade in the carcass class based on the EUROP evaluation grid, leading to decreased quality standards of the carcass and reduced suitability for raw ham production^(3,4,6).

Current literature also indicates that lung lesions, depending on their severity, can cause changes in specific meat traits. The most significant traits include ultimate pH values after the meat maturation process, which can lead to meat defects. Additionally, water-holding capacity is affected, further increasing the risk of defects^(3,4,7). Even small alterations may result in deviations in meat color and flavor, directly affecting the quality of raw pork and making it undesirable for consumers.

Another crucial aspect of meat quality is its utility in meat processing. Reports have indicated that advanced alterations in meat pH values due to lung lesions increase the prevalence of pale, soft, exudative (PSE) meat^(4,7). Additionally, lung lesions contribute to an increased prevalence of dark, firm, dry (DFD) meat^(4,7). PSE pork results from the anaerobic breakdown of muscle glucose, producing lactic acid that lowers muscle pH. This reduction in pH decreases the muscles' ability to retain water. Conversely, DFD pork results from aerobic glucose breakdown without lactic acid production. This leads to high muscle pH and retention of water in the carcass postmortem. Since PSE and DFD pork are rarely considered acceptable to consumers, they can lead to economic losses for meat processing companies due to reduced shelf life, increased risk of consumer rejection, and lower processing quality compared to normal pork.

Additionally, it has been reported that meat obtained from pigs with severe lung lesions has the highest total aerobic bacterial counts, indicating greater susceptibility to rapid deterioration and early microbial spoilage. The shelf life of fresh pork stored at 4°C, acquired from pigs with severe lung lesions, is 3 to 4 times shorter⁽⁷⁾.

The holistic “From Field to Fork” approach to pork as a final product underscores the significant quality changes associated with PRDC in pigs, emphasizing the importance of effective disease management strategies in livestock production. The insights gained from this perspective can inform targeted interventions, ultimately enhancing the economic efficiency and sustainability of pig farming operations.

The authors are confident that this approach will contribute valuable knowledge to the field and encourage further investigation into swine respiratory health. Future research could focus on developing specific intervention strategies to mitigate respiratory diseases, exploring genetic resistance to respiratory pathogens, and optimizing management practices to improve both animal welfare and meat quality.

References

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2. Sibila M, Pieters M, Molitor T, Maes D, Haesebrouck F, Segalés J. Current perspectives on the diagnosis and epidemiology of Mycoplasma hyopneumoniae infection. Vet J Lond Engl 1997. 2009 Sep;181(3):221–31.

3. Permentier L, Maenhout D, Deley W, Broekman K, Vermeulen L, Agten S, et al. Lung lesions increase the risk of reduced meat quality of slaughter pigs. Meat Sci. 2015 Oct;108:106–8.

4. Karabasil N, Čobanović N, Vučićević I, Stajković S, Becskei Z, Forgách P, et al. Association of the severity of lung lesions with carcass and meat quality in slaughter pigs. Acta Vet Hung. 2017 Sep;65(3):354–65.

5. Čobanović N, Stajković S, Blagojević B, Betić N, Dimitrijević M, Vasilev D, et al. The effects of season on health, welfare, and carcass and meat quality of slaughter pigs. Int J Biometeorol. 2020 Nov;64(11):1899–909.

6. Przyborowska-Zhalniarovich P, Maes D, Otrocka-Domagała I, Paździor-Czapula K, Wiszniewska-Łaszczych A, Sołtysiuk M. Association between Enzootic Pneumonia-like Lung Lesions and Carcass Quality and Meat pH Value in Slaughter Pigs. Animals. 2023 Jul 5;13(13):2210.