Attempted conversion of twin to singleton pregnancy in two mares with associated changes in plasma oestrone sulphate concentrations.

The study sought to determine whether the removal of one twin embryo from pregnant mares through the infusion of a saline solution into the gestation sac could successfully lead to a singleton pregnancy, and measured the changes in plasma oestrone sulphate concentrations as a potential indicator of embryonic viability.

Objective of the Research

• The research was conducted with two primary objectives. The first part was focused on experimenting with saline solution to successfully remove one twin embryo, with the hope of inducing a healthy singleton pregnancy. The second aim was to investigate plasma oestrone sulphate concentrations as a potential marker to assess the viability of the embryo.

Methodology

• The researchers conducted a laparotomy (a surgical procedure involving an incision into the abdominal cavity) on two mares, each carrying twin embryos.
• A infusion of 24% saline solution was injected into the gestation sac for the removal of one of the twin embryos.

Results

• The procedure was successful in one mare (Case 1) and the other embryo remained viable. In the second mare (Case 2), neither foetus survived.
• In both cases, the plasma oestrone sulphate (E1S) concentrations dropped immediately following the treatment.
• In Case 1, the E1S concentrations recovered to nearly half of the levels before the treatment. However, the E1S concentrations in Case 2 continued to decline and fell to less than 1 ng/ml within six days of the treatment.

Conclusions

• The researchers concluded that the technique of infusing saline into the gestation sac could potentially serve as a useful method for selectively removing one of twin embryos in mares to trigger single-foetus pregnancies.
• The study also suggested that tracking the concentrations of plasma oestrone sulphate might serve as an effective way to judge the viability of the embryo, given the correlations observed between the treatment and changes in E1S levels.