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

## TL;DR

This study shows that early-life inflammation and necrosis in pigs are linked to tail damage later in life, suggesting early intervention can improve pig welfare.

## Contribution

First longitudinal study linking early-life SINS to tail lesions in pigs, highlighting its role as a preventable welfare risk.

## Key findings

- Pigs with SINS during the weaner phase had a 3.5-fold increased risk of short tails during fattening.
- 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 at the start of fattening and at slaughter.

## Abstract

Tail biting is a highly relevant welfare problem in pigs with undocked tails. This is the first longitudinal study that investigates the correlation between SINS (Swine Inflammation and Necrosis Syndrome) in early life of pigs (suckling piglets and weaned piglets)—and the tail length and tail integrity at the time of fattening and slaughter. In this case, tail biting occurred mainly at the end of the piglet rearing period and at the commencement of the finishing phase, resulting in a reduction in tail length and integrity which was measured at the time of slaughter. The study found a correlation between both SINS in early life and tail lesions later in life, and also with tail length and integrity at the time of slaughter. Several factors that predispose pigs for SINS are known, such as genetics and several housing, feeding and management factors. As this study found a correlation between SINS in early life and later tail issues, this raises the opportunity for prevention and early intervention, to reduce the chances of later welfare issues and therefore improving pig welfare.

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.