# Breed- and Line-Dependent Severity of Inflammation and Necrosis Syndrome in AI Boars, and the Related Risk of Inflammation and Necrosis in Their Progeny

## TL;DR

This study shows that inflammation and necrosis in pigs can be inherited, with boars with severe symptoms passing these traits to their offspring, suggesting selective breeding could improve piglet health.

## Contribution

The study identifies breed- and line-dependent heritability of Swine Inflammation and Necrosis Syndrome (SINS) in AI boars and their progeny.

## Key findings

- Significant differences in SINS severity were found between boar breeds and lines.
- A strong correlation exists between SINS scores in boars and their offspring.
- Heels and claws in boars are more influenced by environmental factors than genetics.

## Abstract

Swine Inflammation and Necrosis Syndrome (SINS) can be detected in different body regions of pigs, such as the tail, ears, teats, or claws, and is an important indicator for health and welfare. Besides environmental influences, genetic factors play a major role in the development of SINS. In this study, we examined boars from different breeds kept at an artificial insemination (AI) station and compared their visible signs of SINS with those of their offspring. We found clear differences between breeds and lines, and a strong association between the severity of SINS in boars and in their piglets. Offspring of boars with the highest SINS scores also showed the most pronounced signs of SINS. However, some changes in heels and claws in the boars were mainly caused by environmental factors. Our findings suggest that pre-selecting AI boars with fewer signs of SINS could help reduce the occurrence of SINS in piglets and thereby improve their health and welfare.

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.