Influence of temperature on prevalence of health and welfare conditions in pigs: time-series analysis of pig abattoir inspection data in England and Wales

Abstract

The prevalence of many diseases in pigs displays seasonal distributions. Despite growing concerns about the impacts of climate change, we do not yet have a good understanding of the role that weather factors play in explaining such seasonal patterns. In this study, national and county-level aggregated abattoir inspection data were assessed for England and Wales during 2010-2015. Seasonally-adjusted relationships were characterised between weekly ambient maximum temperature and the prevalence of both respiratory conditions and tail biting detected at slaughter. The prevalence of respiratory conditions showed cyclical annual patterns with peaks in the summer months and troughs in the winter months each year. However, there were no obvious associations with either high or low temperatures. The prevalence of tail biting generally increased as temperatures decreased, but associations were not supported by statistical evidence: across all counties there was a relative risk of 1.028 (95% CI 0.776-1.363) for every 1°C fall in temperature. Whilst the seasonal patterns observed in this study are similar to those reported in previous studies, the lack of statistical evidence for an explicit association with ambient temperature may possibly be explained by the lack of information on date of disease onset. There is also the possibility that other time-varying factors not investigated here may be driving some of the seasonal patterns.

Prevalence of tail lesions in Swiss finishing pigs

“…In abattoir data from England and Wales, a trend was seen that tail biting increased when temperature decreased. 21 Our findings correspond with such reports concerning the TLS, which was highest in winter. However, results of the TTCS, which was highest in August and September, did not match these reports.…”

“…Such abattoir-specific differences were also observed in another study. 21 It is not unlikely that instructions and regulations enacted and controlled in a federal system lead to variably strict controls and sanctions regarding tail health issues. Another factor could be the selling of animals with severe wounds to small local slaughterhouses before the animals reach the standard market weight.…”

“…1 Impacts that can lead to tail biting are multifactorial and can trigger a tail biting outbreak alone or in combination. Inadequate food composition, 18 inadequate provision of food or water, 15 no or inadequate manipulable objects or substrates, 8 general health problems, 25 gender and unbalanced gender composition in a pen, 20 genotype, 41 large groups and high stocking density, 24 unstable group composition, inadequate environmental climate and season 2,21 In order to retrace the actual origin of the individual animals, the origin marking of each pig was recorded and later merged with the individual herd identifier that is provided by the Swiss animal movement database (TVD-number). 32 A tail length score (TLS) for better comparison of tail lengths of different breeds and weight classes and a tail tip condition score (TTCS) were used for visual grading (Figure 1, based on and adapted from Keeling et al 2012 19 and von Gunten 2016 16 ).…”

Network analysis of pig movement data as an epidemiological tool: an Austrian case study

“…Especially, our results confirmed a greater activity in spring (during the Easter holidays) and autumn (before Christmas) whereas the lowest activity occurred in winter, consistent with other European countries 33 , 79 , 84 . Temperatures play a role on animal health in general, as well as on the maintenance, seasonal pattern, and transmission of infectious pathogens, especially respiratory pathogens 85 , 86 , within livestock trade networks 75 , 87 . Seasonal patterns in the network activities, linked with the swine breeding and production cycle, consumer demand as well as climatic conditions should be considered when planning surveillance activities and responding to an outbreak.…”

The Impact of Air Quality on Sow Feeding and Fecal Health

“…High temperatures can affect the excretion behavior of pigs and reduce their lying time [15,16]. Additionally, the incidence of respiratory system diseases in pigs peaks during the summer months each year, with the opposite pattern observed in the winter months [17]. Compared to temperature, pigs are more sensitive to humidity, and if the relative humidity falls below 40%, it may lead to excessive dust generation, resulting in an increase in pig mortality rate [18].…”