Uterine torsion is responsible for 5-7.3% of dystocias in cattle but is assumed to have a low prevalence in sheep and goats. In cattle the uterus bearing a single foetus is considered to be potentially unstable and may twist following violent foetal movement. In most cases (75%) the uterus rotates in an anticlockwise direction (Noakes et al 2009).
Three ewes were presented for necropsy on 14 August 2014 after the owner reported the sudden deaths of 6 of 2000 first cross ewes prior to lambing. The ewes were generally in fat condition and were running on a mix of improved and native pastures north of Bathurst.
A mature first cross ewe in fat condition was necropsied. The abdomen was distended consistent with a multiparous ewe at term. Mucous membranes were pale. The uterus contained two term foetuses, one with meconium staining (Figure 1). One to two litres of clotted blood were found in the abdomen and a 10 cm long partial to full thickness laceration was noted in the uterine wall (Figure 2). The uterus was rotated clockwise 360 degrees (Figure 3).
There are occasional reports of ovine uterine torsion in the literature (Ijaz and Talafha 1999, Noakes et al 2009, Scott 2011, Naidu 2012). Naidu (2012) successfully reduced torsion by rolling an affected ewe while fixing the uterus with a board held against the abdomen. Naidu also accessed the eastern European literature (citing Selskostopanska 1998 and Minkov et al 1998) and mentioned that Minkov et al reported on 146 cases which they treated surgically with a 95% success rate.
This case is of interest in that the ewe suffered two potentially fatal uterine accidents simultaneously. While this ewe died from blood loss, an undiagnosed uterine torsion would have also led to foetal death, septicaemia and death of the ewe. Presumably a violent foetal movement caused the laceration and initiated the torsion. In the Australian context, uterine accidents including torsions and lacerations, while virtually never reported (to the knowledge of the author), no doubt make a small contribution to ewe mortality across the industry.