Fetal mummification in the major domestic species: current perspectives on causes and management

Abstract

Fetal mummification is an uncommon condition in most domestic species. While most often seen in multiparous and polytocous species like swine, it is also observed in monotocous species when the fetus is retained for a long time. The low prevalence of the condition may help explain the scarcity of information in the literature. To further complicate the study of this phenomenon, the physiological mechanisms that maintain pregnancy vary between species, implying different pathways for the condition. The exact outcome of early fetal mortality is unpredictable, and is influenced by several factors, including the cause of fetal mortality, differences in pregnancy between species, stage of gestation at fetal death, and number of fetuses. Based on our current knowledge of natural fetal mummification events, there are a number of prerequisites for the process of fetal mummification to occur. Examining the circumstances associated with fetal mummification can help scientists better understand the etiology and clinical situation in different species. The objective of this article is to review fetal mummification in the major domestic species: cattle, goats, sheep, horses, swine, dogs, and cats. This paper discusses the clinical situation, the most common and important etiologies, and the treatment approaches for restoring future pregnancy in the female, and where applicable, herd fertility.

Keywords: domestic species; fetus; mummification.

Figure 1

Decision tree for clinical approaches to fetal mummification in cows. Note: Reproduced from Lefebvre RC, Saint-Hilaire E, Morin I, et al. Retrospective case study of fetal mummification in cows that did not respond to prostaglandin F2 treatment. The Canadian Veterinary Journal. 2009;50:71–76. Abbreviations: AI, artificial insemination; Ncr, normal conception rate; Ut, uterine; CR, conception rate; ?, unknown; PGF_2α, prostaglandin F_2α; PGE₂: prostaglandineE₂; $, expensive.