Page 943 - The Veterinary Care of the Horse

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Figure 19.19 Aborted twins

Diagnosis
• In early pregnancy, twinning is diagnosed by routine ultrasound examination per rectum.

• In late pregnancy, the presence of twins can sometimes be detected by scanning through

the abdominal wall.

Subsequent action
Following the diagnosis of a twin pregnancy, there are 3 possible courses of action.

1 Do nothing in the hope that one embryo will die naturally. The mare is checked at day 35

and if 2 foetuses are still present, she should be injected with prostaglandins to abort the
pregnancy.

2 Try to eliminate one of the foetuses manually. If this is done before the embryos attach to
the uterus (i.e. before approximately 15–16 days post ovulation), the success rate can be

up to 90%. The smallest vesicle is gently manipulated until it reaches the tip of one
uterine horn and compressed until it is felt to ‘pop’. If the foetuses are located in the

same horn and have already become fixed to the endometrium, squeezing one is more
likely to result in the death of both of them. If the twins are discovered after 40 days of

gestation, very experienced stud vets may attempt to eliminate one of them by guiding a