Animal health and animal welfare are often considered in isolation of each other. However, there is now a growing awareness of how closely they are inter-related and the importance of this in practical livestock production. Good animal welfare can only be delivered if the animals are feeling physically well and this is acknowledged in the various welfare assessment frameworks which have been established internationally (Figure 1). Conversely, poor welfare is not just a consequence, but also a proven risk factor for many diseases, including the production diseases which were the focus of the PROHEALTH project. The physiological changes which the body undergoes in response to prolonged or repeated stress, such as that resulting from poor housing conditions, lack of social harmony or rough handling, can impair the function of the immune system and reduce resistance to infection.

Figure 1. The role of health in ensuring good animal welfare as reflected in two international welfare assessment frameworks

This interrelationship between animal health and welfare has been demonstrated in the case of pig production in two studies carried out as part of the PROHEALTH project. The first of these was a project carried out in Great Britain by researchers at Newcastle University[1]. They collated historic information about health, welfare and performance from 40 pig finishing farms over a two-year period. The health and welfare data were sourced from two national industry databases recording the results of quarterly scoring carried out by trained veterinarians using standardised protocols.
Health indicators were scored at the abattoir as part of the British Pig Health Scheme, which evaluated 13 different indicators based on examination of the lungs, liver, heart, chest cavity and skin. Welfare indicators were five animal-based measures which were scored on-farm as part of the Real Welfare scheme. After merging information for each farm from these two databases, further information was added about herd production performance and the farm biosecurity scores, which were calculated using the Biocheck-UGhentTM tool. This is a web-based questionnaire and scoring system which has been widely applied to farms across Europe in the PROHEALTH project. The farm biosecurity scores varied widely, ranging from 40 to 90 out of a possible maximum score of 100, indicating that significant scope for improvement was present on many farms. Analysis of the final combined dataset showed that there were a number of significant associations between the pig health and welfare indicators. For example, the prevalence of lameness and severe tail lesions in farm assessments was associated with the prevalence of enzootic pneumonia-like lesions and pyaemia recorded in abattoir assessments. Furthermore, the prevalence of pigs with significant body lesions in farm assessment was associated with several abattoir disease indicators, including peritonitis and milk spot livers. The researchers then went on to use more sophisticated statistical analyses to looks at the different patterns across farms in the indicators of health, welfare and performance. The results of these analyses showed that the farms fell into three groups (Figure 2).

Figure 2. Statistical clustering of farms according to biosecurity, health and welfare indicator scores. The graph summarises the results of a Principle Component Analysis which groups together farms according to their similarity in a range of reported characteristics. The horizontal dimension differentiates farms mainly on the basis of skin lesions, performance and biosecurity scores, whist the vertical dimension differentiates farms mainly on the basis of respiratory disease, lameness and pigs needing hospitalisation.

Farms in Group 1 had lower biosecurity scores, lower growth rate in the finishing pigs and higher prevalence of several disease and welfare indicators such as peritonitis, tail and skin lesions. Farms in Group 2 had higher biosecurity scores, but also a higher prevalence of sick and lame pigs in their welfare assessment and higher finishing pig mortality. Finally, farms in Group 3 had higher biosecurity scores, higher growth rate in the finishing pigs and lower prevalence for welfare problem indicators. These patterns demonstrate how pig health and welfare are linked at farm level, and how biosecurity plays an important role in their determination and performance outcomes.

The second PROHEALTH study to address this topic was carried out by researchers at the Natural Resources Institute (LUKE) in Finland[2] . They collected data from 406 Finnish farms over a three-year period, linking records of antibiotic use recorded in the pig health and welfare classification system (SIKAVA) with quarterly assessments made by the herd veterinarian of biosecurity and animal welfare parameters (including air quality, condition of facilities, cleanliness, enrichment, stocking density, symptoms of diseases) and with data from abattoir inspections on carcass condemnations. In general, antibiotic usage was low, reflecting the relatively high health status of Finnish herds, with the main reasons for treatment being locomotory problems, tail biting and respiratory disorders. The results of the study showed that the count of antimicrobial treatments per pig, and increased condemnations due to lameness or pleurisy, increased with poor condition of watering equipment and poor enrichment provision, as well as a combination of poorer condition of pens and stocking density. This study, therefore, again suggested that by improving biosecurity and welfare on pig farms, animal health could be improved and antibiotic inputs reduced.  

Together, these studies highlight the opportunities offered by exploring the information stored in large-scale national databases to better understand the complex relationships between important farm characteristics and animal outcomes. These data are often collected for other purposes by both public and private sector bodies, and comprise information on large sample numbers which have been recorded over long periods of time. As such, they represent a very powerful and cost-effective approach to address research questions about trends in important livestock farming characteristics and the factors which might be influential in real-world circumstances. As the livestock production sector seeks to meet societal demands by continuous improvement of animal health and welfare, whilst reducing antibiotic use in the face of increasing concern about the spread of antibiotic resistant pathogens into the human medical sphere, such understanding is becoming increasingly necessary and urgent.

[1] Pandolfi F, Edwards SA, Maes D, Kyriazakis I. 2018. Connecting different data sources to assess the associations between biosecurity, health, welfare and performance in commercial pig farms in Great Britain. Frontiers in Veterinary Science, 5: 41.

[2] Stygara AH, Chantziaras I, Toppari I, Maes D, Niemi J. 2018. Is it possible to reduce antimicrobial consumption by improving biosecurity and welfare at pig farms? Proceedings of the 69th Annual Meeting of the European Federation of Animal Science, P562.