Clinical and pathological characteristics in 214 Danish weaners euthanized because of umbilical outpouchings.

Background: Umbilical outpouchings (UO) are common in Danish weaners. In slaughter pigs UOs consist of various pathological diagnoses; however, no studies have assessed the pathology in weaners from randomly selected herds, nor the agreement between clinical examination findings and post-mortem results. The primary objective was to estimate the prevalence of UO-related clinical findings in weaners before euthanasia and the pathologic macroscopic findings after euthanasia. A secondary objective was to assess the agreement between the size of the UO, the presence of ulcers, and the diagnosis before and after euthanasia. Pigs were selected for euthanasia and included in the study because the individual farmer believed the pigs were already unfit for transport, would not make it to slaughter, or would become unsellable.

Results: In total 214 weaners euthanized due to UOs were examined both clinically and post-mortem. Clinically 65.4% of the UOs were large (≥ 11 cm) and 52.3% were unreducible. In the autopsy 78.5% of the UOs were large, and 54.2% had ulcers on their UO. The most prevalent pathological diagnoses were hernia (36.4%), hernia combined with cysts/abscesses (30.8%), cysts (11.7%), and abscesses (11.2%). Adhesions were found in 32.7%, haemorrhage in 22.7%, incarcerated intestines in 8.9%, and connective tissue related to the UO in 51.9% of the pigs post-mortem. The agreement between the size of the UO in the clinical examination and post-mortem was good, as was the sensitivity and specificity for detecting ulcers in the clinical examination compared to post-mortem.

Conclusion: Hernias were the most common pathological diagnosis in weaners euthanized due to UOs, and many pigs had complications related to their UO such as ulcers, adhesions, haemorrhage, or incarcerated intestines-all conditions that could impact the pig's welfare. The presence of connective tissue in the UO in more than half of the pigs indicated that many of the UOs had been present for an extended period. Clinical identification of the umbilical ring is difficult, but the clinical examination is useful for determining the size of the UO and the presence or absence of an ulcer, both critical factors when assessing a pig's welfare and fitness for transport. Clinical examination, however, has limited value in determining the aetiology of UOs.