Ventral rupture and herniation.
Keywords: ventral hernia, ovine, ewe, prematureA primiparous Texel ewe presented for ventral rupture at approximately 144 days of gestation. Her udder was severely edematous and there was also considerable sub-cutaneous hemorrhage. She required help to walk from the truck to her stall. Her appetite was depressed but a a chemistry screen revealed that she was not ketotic. Her CBC and chemistry results were normal. Vitamin E and selenium supplementation in the 74 head flock were optimal. All common vaccinations had been given. The only recent change in management was the introduction of a large Suffolk ram.
Figure 1. A ewe presented for ventral rupture in late gestation. Post mortem examination showed that the mesometrium had been ripped from the peritoneal surface creating a defect in the peritoneal wall (inset at lower left) with the uterus come to lie beneath only a single muscle layer and the skin. Image size: 2788 x 1866 px
Although trauma and the weight of the uterus were suspected as inciting causes in this ewe, many observers have stated that ventral hernia may occur without obvious trauma. Rupture of the prepubic tendon is frequently mentioned in the context of ventral rupture in mares (although this is not necessarily accurate). In several cases, a similar assertion has been mentioned with regard to ewes. However, the author is not aware of any postmortem dissections that have confirmed that view.
Case management:
Because of an anticipated failure of the ewe to exert an abdominal press in second stage parturition, it was decided to deliver her lambs via cesarean section.To mature the lungs of her lambs in utero, 8 mg of dexamethasone was given to the ewe IM. Due to a declining condition of the ewe and a limited budget, the elective C-section was planned for day 145, only one day after presentation. Optimally, more time (~36 to 48 hours) should be allowed for lung maturation after dexamethasone treatment.
Care of neonates:
An epidural anesthetic and inverted "L" were used for the C-section and two live lambs (figure 1) and one dead lamb were delivered. As per usual, suction was used to clear airways of the lambs. Oxygen was supplied using a face mask. Vigorous rubbing and ~ 20 mg of doxapram hydrochloride was used to stimulate respiration in the neonates. Each lamb was tube fed ~35 ml of colostrum (from another ewe on the farm) immediately after birth. When the lambs had become fully vitalized they were offered more colostrum; an essential source of energy as well as antibodies. The final volume consumed by each lamb was just over 100 ml each. The lambs were examined for sex, cleft palate and other abnormalities and their umbilical cords disinfected. In this case chlorhexidine solution was used. The farmer was reminded to repeat this in 24 hours. Until the owner fetched the lambs, they were held in a stall under an infrared lamp at ~ 36 degrees C.
Note: Current literature discourages the use of doxapram in neonatal resuscitation. The use of the GV26 acupuncture site in the philtrum should be considered instead.
The ewe was euthanized.
Postmortem examination:
At postmortem (see figure 1) there was evidence of rupture of the mesometrium and the peritoneal surface on the left-hand side. The uterus was separated from the skin by only a single, stretched muscle layer. It was concluded that an accident such butting, falling or jumping had caused the heavy uterus (containing large Suffolk x Texel triplets) to rip free of the peritoneal surface.
Although trauma and the weight of the uterus were suspected as inciting causes in this ewe, many observers have stated that ventral hernia may occur without obvious external trauma (butting etc.). Rupture of the prepubic tendon is frequently mentioned in the context of ventral rupture in mares (although this is not necessarily accurate). In several cases, a similar assertion has been mentioned with regard to ewes. However, the author is not aware of any postmortem dissections that have confirmed that view.
Selected references:
Huso, B. T. 1941 "Rupture of the Prepubic Tendon of a Ewe," Iowa State University Veterinarian: 3: Article 17
Mahdi A.S. 2015 Ventral abdominal and umbilical hernia in sheep in Babylon. Euphrates Journal of Agriculture Science. 7: 1-7
Monteiro G.A. et al. 2019 Prepubic tendon rupture in ewe. Vet.eZootec.25:085-088
Tirgari M.1980 Ventral hernia in the sheep. Vet Rec.106: 7-9.
