Swine Inflammation and Necrosis Syndrome (SINS) is a simple and non-invasive animal-based health and welfare indicator that combines the clinical observation of bristle loss, swelling, redness, exudation, necrosis and haemorrhage in various parts of the body. It provides a point-of-care measure with direct intervention capability. Several studies from different countries demonstrate its considerable prevalence, particularly among newborn, suckling and weaned piglets. The syndrome has been demonstrated to be endogenous, as evidenced by clinical, pathohistological, clinical chemical, metabolomic, transcriptomic and genomic analysis. It has been established that the first and fourth weeks of life represent suitable time points for examination. However, longitudinal follow-up of individual animals has hitherto been lacking. In order to address this issue, a total of 1080 complete SINS examinations were conducted on 59 piglets at days 1 to 14, 19, 22, 26 and 41 of life. The findings substantiate the bimodal progression and evince a robust correlation between signs in disparate anatomical regions, including body temperature. Two peaks with significantly increased SINS signs were observed, the first around the fourth day of life and the second around day 26. The majority of indications of SINS in the second peak manifested prior to the initiation of the weaning process. The development of SINS signs in the piglets as a group followed a clear pattern. However, it was not feasible to predict the subsequent course of SINS based on individual animals. It is recommended that SINS, as an animal-based health and welfare indicator, be screened on days three to four and/or in the fourth week of life. It is imperative that the day of life is specified with the greatest possible precision, given the propensity for considerable deviations to occur within a time frame of one to three days, especially during the initial week of life. The implementation of these findings has the potential to make a decisive contribution to improving inventory herd analyses and studies on SINS, thereby improving the welfare and health of piglets.

Animal-based measures, such as detecting inflammation in areas like the tail, ears, teats, coronary band, heels and claws (Swine Inflammation and Necrosis Syndrome, SINS), are used to monitor animal health and welfare. When parameters deviate from the established range, these measures enable prompt action to adjust husbandry practices, feeding regimens and management strategies. In addition to environmental factors, genetics have been shown to play a key role in inflammation and necrosis processes, and selection can reduce the severity of the disease. This study examined whether different breeds of AI boar exhibit different signs of SINS and how these signs are associated with SINS in their offspring when they are suckling piglets and weaners. Initially, 286 AI boars of 7 breeds from a German artificial insemination center were evaluated for SINS. The following parameters were assessed: tail base, tail tip, ears, skin, scrotum, coronary bands, heels and claws. Subsequently, 23 Pietrain and Duroc boars were used in combination with a Topigs DL sow line. The progeny of the AI boars was evaluated as suckling and weaned piglets, with the assessment framework encompassing SINS traits. The results revealed significant differences between the breeds and lines, as well as a strong correlation between the SINS phenotypes of the AI boars and the SINS scores of their offspring. The offspring of the 25% most extreme boars exhibited a 17% variation in SINS scores. This association was particularly evident when comparing the boars’ tail base. However, the development of the boars’ heels and claws was found to be significantly influenced by mechanical environmental factors and not associated with the piglets’ scores. These findings imply that heritable, endogenous processes, as proposed for SINS, also visibly impact the phenotype of the AI boar. This study’s fundamental premise suggests that pre-selecting AI boars could mitigate the occurrence of SINS and enhance piglet health and welfare.