Clint Lichty from South West Ontario Veterinary Services, Can We Predict Outcomes For Pigs With Umbilical Outpouching

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Previous studies have revealed that what we traditionally describe as an “umbilical hernia” may be a true abdominal herniation of abdominal contents into a pouch at the site of the umbilical cord or they may be a firm abscess that is not currently connected to the abdominal cavity. Some studies have further demonstrated that umbilical abscesses will frequently become umbilical hernias. Prior to slaughter or post mortem it can be difficult to determine an umbilical abscess from an umbilical hernia. Some researchers prefer to describe the condition as an “umbilical outpouching or bulge”.  The Canadian Code of Practice for the Care and Handling of Pigs provides guidance with respect to humane handling of pigs with umbilical bulges / hernia. In addition, the Canadian Food Inspection Agency (CFIA) through it’s authority to regulate the transportation of livestock provides guidance as to when pigs should or should not be transported. Pigs with a large umbilical hernias that can impede movement, is painful on palpation, touches the ground when the pig is standing in its natural position or has an open skin wound, ulceration, or obvious infection should not be transported even with special provisions. Personnel at both Provincially and Federally inspected plants may choose to euthanize pigs with large umbilical hernias when they arrive at an abattoir. In Ontario, every person who has care or control over a fallen animal must promptly destroy the animal in a humane manner or to make arrangements for it to be promptly and humanely destroyed. Pigs with very severe hernias that have become infected or injured usually fall under this classification.

These Danish researchers wanted to better understand the role of umbilical outpouchings (UOs) in affecting various possible production outcomes. The objectives of the study were to characterize the associations between 1) time of detection of the UOs and the odds of dying before scheduled slaughter; 2) time of death, irrespective of the cause, and clinical signs of the UOs, i.e. general condition, size, reducibility, form and skin-color of the UOs; and 3) occurrence of wounds on the UOs and clinical signs: general condition, size, reducibility, form and skin-color. A cohort of Danish conventional pigs with UOs (n = 255) were followed from the detection of an UO until spontaneous death, euthanization or slaughter of the pig. The pigs were clinically examined once a month. If pigs with an UO died spontaneously, were euthanized or slaughtered, the causes and date of death were recorded.

The researchers found the following:

  • 57 % of the pigs died spontaneously or were euthanized before slaughter. The median age of spontaneous death or euthanasia was 85 days.
  • Umbilical outpouchings were detected at different ages, with half of the pigs (52 %) detected in the farrowing section. No significant association was found between death before scheduled slaughter and the time of detection.
  • An interaction was present between the size and the skin-color of the UO.
  • Wounds on the UO were the most frequent complication resulting in euthanasia (37 %). The odds for developing a wound on the UO were higher for pigs in a general bad condition compared to pigs in a good condition (OR, 5.4; 95 % CL 2.5-11.3), and for pigs with an UO large in size compared to pigs with a small UO (OR, 4.8; 95 % CL 3.0-7.5).

Take Home Messages:

  • Pigs with large outpouchings are a significant risk of spontaneous death or euthanasia prior to normal slaughter weight.  These results confirm the findings of previous studies.
  • The presence of wounds on an umbilical outpouching was highly predictive of a bad outcome and the odds of developing a wound was greater in pigs that were already in poor body condition and for larger hernias.
  • This research indicated that about half of the outpouchings could be detected in the farrowing section. This would appear to be a much earlier detection rate than previously reported.
  • Speedy identification and euthanasia of pigs with larger umbilical outpouchings / hernias especially when the outpouching has a wound is essential to demonstrating our commitment to animal welfare.

Ref: Trine Hovmand-Hansen , Søren Saxmose Nielsen , Tina B Jensen , Kaj Vestergaard , Mai Britt F Nielsen, Henrik E Jensen   Survival of pigs with different characteristics of umbilical outpouching in a prospective cohort study of Danish pigs Prev Vet Med . 2021 Apr 10;191:105343. doi: 10.1016/j.prevetmed.2021.105343. Online ahead of print.