Improved embryo recovery through increased flushing media volume and the impact on unintended pregnancies in a single subject donor mare

Abstract

The case report discusses the implications of using different volumes of flushing media during embryo flushing (EF) procedures in a single donor mare that experienced multiple unintended pregnancies following negative EF outcomes. The study involved two sets of EF experiments over two years on a non-lactating Spanish purebred mare. The initial experiments (group 1, n = 6) used 1 L of flushing medium (Ringer´s Lactate), and subsequent tests (group 2, n = 5) increased the volume to 2 L, to assess whether a larger volume could enhance embryo recovery rates. After every EF procedure, no PGF2α was administered. The overall frequency of double OV was 36.3 %, and did not vary (p > 0.05) between group 1 and 2 (33.3 % and 40 %). The results indicated a significant improvement (p < 0.05) in embryo recovery rates with the increased medium volume (group 1, 25 %; group 2, 85.7 %). A tendency was noted (p = 0.06) for more positive EF outcomes in group 2 (100 % positive outcome). The number of unintended pregnancies observed was significant (p < 0.05) between groups (group 1, 4/8; group 2, 0/7). The study concluded that a higher volume of flushing medium yields a higher embryo recovery rate and minimizes unintended pregnancies in the subject mare.

Keywords: Embryo flush; Horse; PGF2α; Pregnancy.