Twinning in the mare is a frequently occurring phenomenon which should
be noticed on time. The earlier the diagnosis is made, the better the
results from treatment which may be given. When the diagnosis is made
after the formation of endometrial cups (around the thirty-fifth day
of pregnancy), only a few options are available: manually rupturing on
e vesicle, starvation of the mare, performing abdominal surgery in ord
er to remove one conceptus or attempting a puncture of one of the vesi
cles or fetuses. Vesicle or fetus puncture is a relatively new techniq
ue which at the current time has not yet been refined. In this case re
port a mere is discussed with a forty-seven days old unilateral twin p
regnancy with contact between the two embryonic vesicles. In this mare
the tain pregnancy was successfully reduced by a transvaginal ultraso
und-guided puncture of one of the twins.