A RETROSPECTIVE STUDY OF DYSTOCIA IN EASTERN INDIGO SNAKES (DRYMARCHON COUPERI).

Abstract

Medical and husbandry records of eastern indigo snakes (EIS) (Drymarchon couperi) housed at the Orianne Center for Indigo Conservation (OCIC) were reviewed to determine risk factors for developing dystocia. Thirty-four cases of dystocia were identified out of 104 successful breeding events between 2010 and 2020. The number of breeding events, age, body weight, housing, and selected blood parameters were reviewed for the female EIS successfully bred at OCIC between 2010 and 2020. Categorical data were evaluated with chi-square and the Fisher exact test, and the continuous data were evaluated using analysis of variance. Differences in data were considered statistically significant when P < 0.05. There was a significant difference seen between EIS that developed dystocia (EISd) and EIS that did not (EISn) for breeding events, with the virgin breeding event having more EISd than any other breeding event. Risk analysis of the data revealed that EIS were 9.28 times more likely to develop dystocia during the virgin breeding event than on subsequent breeding events. Age and housing were not significantly different between EISd and EISn for each breeding event, but body weight was, as EIS weighing less than 1.5 kg were found to be 4.43 times more likely to develop dystocia. There was also a significant difference between EISd and EISn in plasma sodium, calcium, ionized calcium, glucose, and albumin. When compared to EISn, EISd had lower plasma sodium, calcium, ionized calcium, and albumin and higher plasma glucose. There were also significant differences in the white blood cell differential count, as EISd had lower basophils and monocytes when compared to EISn. The majority of EISd were managed surgically, and retained eggs were more likely to be located within the right oviduct. This retrospective study is the first to evaluate potential causes of dystocia in EIS.