Factors associated with ewe and lamb survival, and subsequent reproductive performance of sheep undergoing emergency caesarean section

Abstract

Clinical records of all 212 ewes undergoing emergency caesarean surgery at a veterinary teaching hospital between January 2008 and December 2019 were evaluated retrospectively. Their age ranged from 1 to 10 years (median = 4 years), with German merino the predominant breed (48.1% of cases). The most frequently diagnosed indications were insufficient cervical dilatation (n = 94, 44.3%), uterine torsion (n = 50, 23.6%), foetopelvic disproportion (n = 31, 14.6%) and vaginal prolapse intra partum (n = 11, 5.2%). Fifty‐four (25.5%) of the 212 ewes additionally suffered from one or more concurrent, pre‐existing conditions. Overall ewe mortality until hospital discharge was 10.8% (23/212), and 3.8% (n = 6) for the 158 ewes without a history of concurrent disorders. Mortality during hospitalization increased to 31.5% (17/54) for those with pre‐existing conditions. Total lamb mortality was 49.1% (173/352) until hospital discharge. Pre‐existing conditions (p = .001) and the presence of post‐surgical complications (p = .025) were identified as significant factors influencing dam mortality, while delayed presentation for veterinary attention with an observed duration of labour of >12 hr was identified as the most influential factor on total lamb mortality (p = .010). The presence of dead or emphysematous foetuses was not significant for ewe mortality. Follow‐up information on further outcomes was available for 156 (82.5%) of the 189 discharged ewes. Eighty‐nine animals (57.1%) were re‐bred in the following season and achieved a 93.3% (83/89) pregnancy rate, while the remainder had either been slaughtered (n = 56, 35.9%), sold (n = 5, 3.2%) or had died of unknown causes (n = 3, 1.9%). The subsequent incidence of dystocia was 15.6% (n = 12) in the 77 ewes with available information on lambing ease. Adequate management of underlying conditions and timely intervention are important factors for best possible short‐term outcomes. In the long term, the subsequent pregnancy rate was good and the incidence of subsequent dystocia was within the normal range.

Retrospective analysis of 302 ovine dystocia cases presented to a veterinary hospital with particular attention to uterine torsion

“…Some cases of foetal malformation were also observed (9/95, 9.5%). Dystocia was resolved by manual correction in 71 of the 302 cases (23.5%), while 225 animals (74.5%) were treated by caesarean section as previously described (Voigt et al., 2021). A partial foetotomy (Winter, 1999) was performed in six ewes (2.0%).…”

“…Maternal causes of dystocia are therefore often the leading causes reported in these study types (Brounts et al., 2004; Ennen et al. 2013; Sobiraj, 1994; Voigt et al., 2021). Among maternal causes of ovine dystocia, incomplete cervical dilatation is the most frequently reported problem, while other causes such as uterine torsion are considered rare in sheep (Jacobson et al., 2020; Parkinson et al., 2019a, b; Winter, 1999) in contrast to other ruminants.…”

Analysis of pH and Electrolytes in Blood and Electrolytes in Ruminal Fluid, including Kidney Function Tests, in Sheep Undergoing General Anaesthesia for Laparotomy

“…Moreover, in Germany, application of non-steroidal anti-inflammatory drugs (NSAIDs) in sheep require drug repurposing from other species. Voigt et al found that most ewes are presented for SC due to insufficient cervical dilatation (44.3%) [ 4 ]. Maternal survival rate was described as 97.8% under field conditions [ 4 ] and in studies comparing elective SC to vaginal delivery, postnatal deaths in ewes are similar [ 5 ].…”

“…Voigt et al found that most ewes are presented for SC due to insufficient cervical dilatation (44.3%) [ 4 ]. Maternal survival rate was described as 97.8% under field conditions [ 4 ] and in studies comparing elective SC to vaginal delivery, postnatal deaths in ewes are similar [ 5 ]. In ewes presented at a veterinary teaching hospital, ewe mortality up until hospital discharge was 10.8%, as survival rate is mostly influenced by delayed presentation to a veterinarian [ 4 ].…”

“…Maternal survival rate was described as 97.8% under field conditions [ 4 ] and in studies comparing elective SC to vaginal delivery, postnatal deaths in ewes are similar [ 5 ]. In ewes presented at a veterinary teaching hospital, ewe mortality up until hospital discharge was 10.8%, as survival rate is mostly influenced by delayed presentation to a veterinarian [ 4 ]. In the following season, previously operated ewes gave birth to fewer live-born lambs, but birth weight and conception rate were not influenced [ 5 ].…”