Umbilical outpouchings (UO) is a relatively recent description for what was considered to be umbilical hernias. It has become more clear over time that UO is a more appropriate term that encompasses the full scope of the problem. The appearance of a “bulge” in the belly at the location of the umbilicus is really just the “tip of the iceberg”. (Photo 1) Some of these UO may be an uncomplicated umbilical hernia but may also be associated with hernias, cysts, abscesses, generalized peritonitis or combinations thereof. Pigs with UO are at increased risk of mortality. The welfare implications of UO are taken very seriously in many pig producing jurisdictions (including Canada). The Danish industry in particular mandates that pigs with UO must be segregated into a pen with deep bedding and if the UO is deemed to be large (≥ 11 cm) the pigs can not be transported without a veterinary certificate. The Danes are making considerable effort to understand the various causes of UO in the hope of improving animal welfare and reducing the costs of UO to producers and processors.
What Is The True Prevalence Of UO In Danish Pork Production? (Ref 1) This study aimed to estimate the prevalence of UO in Danish piglets and weaners and describe their clinical characteristics including size, texture, reducibility, and occurrence of ulcers.Risk factors for the occurrence of ulcers on UOs were also investigated. A cross-sectional study was conducted in 30 Danish conventional herds, with at least 800 weaned pigs and 200 sows. Piglets were examined during their last week in the farrowing unit, and weaners were examined and palpated between weeks three and eight after weaning.
The researchers found the within-herd prevalence of piglets with UO averaged 4.2% with a range from 0.8 to 13.6% between herds. The within-herd prevalence of weaners with UO averaged 2.9%, ranging from 1.0 to 5.3% between herds. Approximately 80% of the UOs were classified as small or medium (< 7 cm piglets/ < 11cm weaners). Large outpouchings had significantly higher odds of skin ulcer occurrence (OR = 9.9, p < 0.001). Probably 1 million pigs affected with UO / year in Denmark.
Does Lifting Young Piglets By the Hind Leg Cause Increased UO?: (Ref 2) It has been suggested that lifting young piglets by one hind leg may be a risk factor for developing inflammation of the umbilical cord and subsequently could increase the incidence of umbilical hernias. Although this seems like a reasonable hypothesis it has never been fully investigated. The thought was that lifting piglets by one hind leg could stretch the umbilical wall and impede the healing of the umbilicus. The researchers studied 1901 piglets that were assigned to either Group 1 (986 piglets) where piglets were caught, lifted, and carried by one hind leg (either left or right) or Group 2 (915 piglets) where piglets were caught, lifted, and carried with full support under the abdomen. Piglets were lifted somewhere between 8 to 10 times during the first 2 weeks of life during regular farrowing room management procedures. There were 50 randomly selected female piglets from each group that were euthanized for necropsy and microscopic examination.
Findings: The researchers did not detect any significant difference between pigs picked up by one hind leg vs picked up by cradling the piglet under the belly with respect to inflammation of the umbilical tissues, evidence of umbilical herniation or hind leg joint lesions.
How Accurately Can We Predict What Is Really Going On Inside An Umbilical Outpouching in Weaners? (Ref 3) These researchers wanted to compare the clinical findings of UO in weaners before euthanasia and the pathologic findings after euthanasia. They also wanted to determine how accurately the actual size of the outpouching is described clinically vs at post mortem. Pigs were enrolled in the study and then euthanized if the farmer believed the pigs were unfit for transport, would not likely make it to slaughter or would become unsellable in the future. This is pretty much the universal decision dilemma faced by producers when trying to predict the future for growing pigs with a visual UO.
Findings: The researchers found that of the 214 pigs euthanized due to UOs there were 65.4% of the UOs that were identified as large (≥ 11 cm) and 52.3% could not be pushed back into the abdomen (unreducible). At autopsy 78.5% of the UOs were determined to be large, and 54.2% had ulcers on the UO. Within the UO there were hernias (36.4%), hernia combined with cysts/abscesses (30.8%), cysts (11.7%), and abscesses (11.2%). When there was a herniation of abdominal organs into the hernia there were adhesions found in 32.7%, haemorrhage in 22.7%, incarcerated or trapped intestines in 8.9%, and connective tissue related to the UO in 51.9% of the pigs. All of these conditions could negatively impact the pig’s welfare, survival or chances of condemnation. 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 of time. Clinical examination, has limited value in determining the aetiology of UOs but accurate evaluation of size is helpful in determining a prognosis.
Take Home Messages:
- The Umbilical Outpouching is often just the “tip of the iceberg” with respect to the complications associated with UO. The “Battle of the Bulge” is often more complicated than you might initially expect.
- Pork producers are pretty accurate at assessing the severity of UO and taking appropriate action that can maintain animal welfare as well as minimizing the associated production and condemnation costs.
- “Your first loss is your best loss!” Trusting your first instincts and taking action early will improve animal welfare and minimize production and condemnation losses.
- If you are having a challenge with umbilical outpouchings please don’t hesitate to contact your herd health veterinarian and health team for advice on putting a control plan in place.
Reference 1: Marie-Louise Hansen, Tina Birk Jensen, Charlotte Sonne Kristensen, Inge Larsen & Ken Steen Pedersen Umbilical outpouchings in Danish piglets and weaners: prevalence and clinical characteristics—a cross-sectional study at herd level Porcine Health Management volume 10, Article number: 3 (2024) Cite this article
Reference 2: Kristiane Barington , Marie Høy Hansen , Amanda Bastian Andersen 2 , Ken Steen Pedersen2 , Inge Larsen Does lifting female piglets by one hind leg increase the risk of umbilical and hind leg lesions? Porcine Health Manag . 2024 Dec 20;10(1):61. doi: 10.1186/s40813-024-00413-6.
Reference 3: Marie-Louise Hansen , Inge Larsen , Tina Birk Jensen , Charlotte Sonne Kristensen , Ken Steen Pedersen Clinical and pathological characteristics in 214 Danish weaners euthanized because of umbilical outpouchings Porcine Health Manag . 2024 Nov 22;10(1):54. doi: 10.1186/s40813-024-00401-w.
