# Periweaning failure to thrive syndrome (PFTS): A growing concern in swine health

## TL;DR

PFTS is a poorly understood syndrome in pigs that causes growth issues and unclear causes, requiring more research for effective diagnosis and treatment.

## Contribution

This review synthesizes current knowledge on PFTS, highlighting gaps in understanding its multifactorial aetiology and diagnostic challenges.

## Key findings

- PFTS is characterized by growth retardation and specific histological lesions in weaned pigs.
- Potential contributing factors include infectious agents, genetic predisposition, and nutritional deficiencies.
- Diagnosis relies on gross and histological observations due to the syndrome's complex and unclear aetiology.

## Abstract

Porcine Periweaning Failure to Thrive syndrome (PFTS) is a complex and scarcely investigated syndrome that has been of increasing concern in the swine industry during the last decade. Its aetiology is believed to be multifactorial, and although both infectious and non-infectious factors may be involved, including a possible genetic predisposition, consistent association needs to be elucidated.

PFTS is characterised by growth retardation and non-specific clinical symptoms that may include progressive debilitation of weaned pigs that typically emerge within two to three weeks after weaning and repetitive oral behaviour such as chomping and licking. Currently, the diagnosis of the syndrome is based on gross examination, where the main observation is a thymus severely atrophic and the gastrointestinal tract empty, and the following characteristic histologic lesions: thymic atrophy, superficial lymphoplasmacytic fundic gastritis, villus atrophy in the small intestine, superficial colitis, lymphocytic and neutrophilic rhinitis, and mild nonsuppurative meningoencephalitis. Research on PFTS has explored various factors contributing to the syndrome, including viral agents, genetic predisposition, and nutritional deficiencies. Studies have identified potential infectious agents, but the definitive association with the syndrome remains unclear. Genetic predisposition has also been suggested to play a role during PFTS, identifying potential boars to individually contribute to PFTS and paternity tests have linked affected piglets to certain boars, suggesting individual susceptibility. In this review, we will explore the contributing factors which may be involved in the development of the syndrome, as well as examine the current knowledge on its diagnosis and pathogenesis.

PFTS presents a significant challenge in the swine industry due the unknown aetiology and the difficulty to establish an appropriate diagnosis of the syndrome. Therefore, additional research is needed to investigate the microbial, genetic, and environmental factors that influence PFTS, as this is crucial for developing targeted control measures and potential treatments.