Early-Life Swine Inflammation and Necrosis Syndrome Is Associated with Later Tail Integrity and Systemic Hematological Changes in Organically Raised Pigs

Swine Inflammation and Necrosis Syndrome (SINS) is a widespread condition in pigs and has been proposed as an early-life animal-based measure (ABM) for assessing health and welfare. However, its prognostic value for later-life outcomes under commercial conditions remains poorly understood. This study investigated the prevalence, progression, and predictive relevance of SINS in two organic pig farms in the Netherlands. Clinical SINS signs were assessed in suckling and weaned piglets and related to hematological parameters at weaning (35 weaned piglets) as well as tail integrity at slaughter. SINS lesions were highly prevalent in suckling piglets (approximately 80%) but markedly decreased after weaning. Lesion prevalence and severity differed substantially between farms and showed clear age-dependent patterns, peaking between days 3 and 5 of life. Higher SINS scores in suckling piglets were associated with systemic hematological alterations at weaning, including increased monocyte proportions, reduced platelet counts, and altered red blood cell indices. Importantly, early-life SINS was significantly associated with later tail integrity. Pigs with higher SINS scores showed a lower probability of intact tails at slaughter and subsequently a higher prevalence of tail lesions. These findings suggest that SINS may have potential as an early-life indicator of later tail outcomes; however, this hypothesis requires validation in larger studies involving a greater number of farms and production systems.