Longitudinal Study: Swine Inflammation and Necrosis Syndrome in Suckling and Weaned Piglets Is Associated with Tail Length and Integrity in Slaughter Pigs.

Swine Inflammation and Necrosis Syndrome (SINS) is a highly prevalent, predominantly endogenous condition that compromises tissue integrity and animal welfare across different life stages in pigs. Increasing evidence suggests that early-life SINS lesions may predispose pigs to tail damage later in life; however, longitudinal data remain scarce. This study investigated the association between SINS-related clinical signs in suckling piglets and weaners and subsequent tail integrity during fattening and at slaughter. In a longitudinal study, 352 piglets from two Italian farms producing Parma ham were followed from the suckling phase to slaughter. Although SINS signs were generally mild, pigs affected during the weaner phase showed a 3.5-fold increased risk of developing short tails during fattening. Furthermore, the probability of reduced tail length at slaughter increased from 33.5% to 65.8% in pigs with a history of SINS. Early-life SINS was significantly associated with impaired tail integrity both at the onset of fattening and at slaughter. These new findings highlight endogenous inflammation and necrosis in early life as important yet underrecognized welfare risk factors and suggest that SINS can be utilised as a point of care and early preventive strategies may substantially improve tail integrity and welfare outcomes at slaughter.