Meet the twins (yet to be named), together with proud mum Katy, a grey Sports Horse mare. These two adorable and very lucky youngsters are now over 6 months old. It is remarkable that they both survived, never mind that they are so well grown and similar in size. They are owned by Billy Hartley in Astley and I am sure he is looking forward to competing in the ridden pairs when these two are ready!
It is unusual to see a healthy pair of twin foals as pictured. Indeed it is exceptionally rare that both twins survive the pregnancy let alone to have both born and survive. The usual outcome would be that the weaker twin would either be stillborn or in a very weak state and wouldn’t survive very long after it was born. It would also not be surprising if the stronger twin presented with problems due to a lower birth weight and ultimately die. In some situations the twin pregnancy is unknown as the pregnancy fails and the embryos are reabsorbed during the pregnancy. Some may abort the twins at 7/8 months of gestation.
As can be imagined, the reason for this poor outcome is that the foals compete for space and nutrients within the mare’s womb. It is an immense drain on the mare’s energy reserves to try and sustain and nourish two developing foals and consequently preference is given to one of the foals to receive more nutrients and space than the other.
It cannot be stressed enough how dangerous and potentially life threatening it is for a mare to be having twins.
Whilst working in New Zealand , I was called to a mare that was having difficulty in foaling. The mare was thought to be only having a single foal as is normal, she hadn’t been scanned to prove otherwise. The foal’s head was presenting along with only one leg. The mare had also prolapsed approximately one foot of her rectum; this gave the mare a very poor prognosis for survival even if she foaled normally. As I tried to feel inside the mare and free the foals twisted leg I could feel another head which was effectively blocking the foals trapped leg and leaving me unable to push the foal back to create more space. Unfortunately, the first foal, which was already in a weakened state died and the mare, was put to sleep given the hopeless situation she was in. Even if the foals could be removed she had a hopeless prognosis afterwards, given the prolapsed rectum. A post-mortem was performed and the second foal had indeed wedged itself into the mare’s pelvic canal, thus causing the first foal to be stuck in both directions. This was a very upsetting situation and a devastating outcome for both mare and owner. It only serves to highlight the danger associated with a twin pregnancy in horses.
This situation can be prevented by simply having your mare ultrasound scanned after covering to detect a twin pregnancy. The ultimate time for this to be performed is 14-16 days after the mare was covered. This will not only confirm that conception has occurred but will also allow detection of a twin pregnancy.
If a twin pregnancy is imaged then there are three possible courses of action. Firstly one of the embryos can be popped using the ultrasound scanner. This requires a relative amount of skill at this early stage of pregnancy and isn’t without its risks as it can also inadvertently destroy the other embryo too. Secondly the pregnancy can be left until 30 days of gestation, as this will give the mare time to naturally reabsorb one of the embryos as this can commonly occur with twin pregnancies. The final option at either stage of gestation is to administer a drug, which will abort both embryos. The mare can then be put back into heat and bred again. If the pregnancy goes beyond 37 days and twins are still present then the situation is much more difficult to control and the pregnancy may have to be left to run its course whilst keeping fingers and toes crossed.