Icelandic Horse Twins--A Wonderful and Cautionary Tale

On July 1 2014 Kathy Lockerbie, owner of Silver Creek Icelandic Horses in Bellingham WA, walked into the pasture to check on her pregnant mare Aska. Much to her surprise, she found two pinto babies. The small black and white filly tottered about looking for milk and a tiny grey and white colt lay motionless in the field.  She immediately called her veterinarian, Dr. Don Beckman, who asked if both foals were alive. When told they were, he responded “Well, you have already beat the odds.”  Little did Kathy know how great those odds really were.

 
Upon arrival, Dr. Beckman of Mt. Baker Veterinarians found the filly, weighing around 75 pounds, nursing but the colt, weighing only about 50 pounds, struggling on the ground. The colt needed milk as soon as possible, both for nutrition and the colostrum required in the first 24 hours of life to develop normal antibodies.  A new born horse has no natural immunization and requires one to two pints of colostrum from its mother to develop normal antibodies.  The colostrum has to be received its first 24 hours of life to be absorbed and it is critical that the foal receive 85% of that within the first 8 hours of life.  Typically a mare only produces enough colostrum for one offspring so the horse owner of twins may need to purchase additional, expensive colostrum.
 

When several attempts to get the colt to nurse failed, Dr. Beckman and Kathy’s daughter Helen inserted a gastric feeding tube down the colt’s nasal passage.  Kathy was instructed how to milk Aska and express the milk through the feeding tube into the colt’s stomach. The colt, now named Bróðir (Icelandic for “brother”) required supplemental gastic feeding every two hours for the first three days.  By the third day, Bróðir was able to nurse on his own despite filly Systir awkwardly kicking at him.

Twinning in horses is almost always the result of a double ovulation (identical twins are extremely rare in horses).  Double ovulation rates vary by breed--30% in thoroughbreds, Warmbloods, draft horses and Arabians; 5% to 10% in Quarter Horses; less than 1% in native British ponies; unknown in Icelandics.  The chances of a double ovulation are higher for young mares age 6 to 8; non-lactating mares;  older, previously barren mares; and mares with a genetic predisposition for twins.

While watching horse twins play is ever so heartwarming, Dr. Beckman says, “Twins are trouble.”

Unfortunately, a mare is not designed to support two fetuses at the same time.  The placenta almost always provides sufficient oxygen and nutrition for the healthy development of one fetus.  The statistics for survival of the mare and both twins after birth are daunting: less than 1 in 100.  If one considers the abortion rate after conception, the actual odds are more like 1 in 100,000 for long term survival of mare and twins. 

Most often one of the twins is naturally aborted in mid to late pregnancy, usually the smaller, weaker one.  Premature birth, retention of placenta, death of one or both twins, deformities, development of laminitis in the mare, difficult labor resulting in trauma, decreased likelihood of pregnancy during the next breeding season, and even death of the mare are all associated with twins.  Even if the foals survive, they may remain weak, underdeveloped and fragile.  Twins are usually  a heart breaking and expensive scenario for the owner.

Dr. Bechman suggests that a mare get an ultrasound 14 to 16 days after breeding.  If twins are detected, one of them can be manually reduced with a success rate of the other twin surviving of about 100%.   After 25 days the procedure involves aspiration of one twin with a greater chance of complications and the success rate drops to 40 to 70%. As the pregnancy advances, the interventions become more involved with even lower success rates.

Kathy Lockerbie was fortunate in her choice of breeds.  Icelandics mares are typically quite fertile.  Under old style Icelandic husbandry practices, the mare Krossa at age 34 delivered her 31^st foal.  All of her offspring survived, despite the fact that she had never been stabled.  World Fengur, the stud book of the Icelandic horse, records 20 sets of twins that were born and survived worldwide from 1999 to 2013. Kathy’s twins are the first to be born in North America. 

Researchers at Hvanneyri Agricultural University in Iceland found that a mare (an Icelandic mare averages around 600 to 700 pounds) in good condition can produce as much as 4.2 gallons of milk per day enabling the average foal to gain up to 4.5 pounds per day.  The average thoroughbred or large breed mare produces 2.6 to 4.7 gallons per day. Of course quality food and supplements can result in higher quality and quantity of milk production. Kathy fed Purina Omolene #300, a supplement for lactating mares, to Aska for the first two and one half months.

At four months of age, Bróðir and Systir are thriving.  Syster is almost normal weight for her age and Bróðir is gradually catching up.  Their mother Aska is also in good condition.  Dr. Beckman only needed to make two visits to the farm, one to insert the gastric tube and one to remove it.  Kathy has started working with the twins on basic halter training.  Bróðir and Systir have the typical easy going Icelandic temperament of their sire Lani from Aflasaga, although Systir continues to kick her brother when he nurses.

Kathy is so grateful that her Icelandic horse family beat the odds.  Since Aska may be at higher risk to have twins again, Kathy plans to use ultrasound around 15 days into the next pregnancy and take the appropriate steps to avoid them, if necessary. 

“Why risk those astronomical odds again?” concludes Kathy.

You can find more photos of Aska and the twins at:

http://nwhsphoto.smugmug.com/Equestrian-Events/Icelandic-Twin-Foals/i-XF4Jdsv

Video of twins documenting birth of twins can be viewed at: https://www.youtube.com/watch?v=xd-SactnSDo

A version of this article was first published in the NW Horse Source at:
http://www.bluetoad.com/publication/?i=240012#{"issue_id":240012,"page":26} 

 Thanks to Catherine Madera of this publication for her edits.

Resources:

Bjőrnsson, G., & Sveinsson, H.  (2006).  The Icelandic Horse, Edda Publishing, Reykjavik, Iceland.

Domer, L.  (2009).  Double Trouble, Part 1.  America’s Horse Daily.  http://americashorsedaily.com/double-trouble/#.VEDiXvnF8uc

Dýrmundsson, O.  (1994).  Reproduction of Icelandic Horses with special reference to seasonal sexual activity.  Icelandic Agricultural Society, 8: 51-57.  http://www.landbunadur.is/landbunadur/wgsamvef.nsf/0/a93b6cee824dea3000256dfe004cb962/$FILE/gr-bu8-ord.PDF

King, M.  (March 1, 2001).  The Trouble with Twins.  http://www.thehorse.com/articles/10041/the-trouble-with-twins

Morel, M.  (January 1, 2002).  Mother’s Milk: Understanding Mare Lactation, http://www.thehorse.com/articles/12798/mothers-milk-understanding-mare-lactation

Thomas, H.  (May 16, 2014).  Seeing Double.  http://www.thehorse.com/articles/33858/seeing-double

Twins.  (n.d.)  Goulburn Valley Equine Hospital.  http://www.gvequine.com.au/reproduction/ultrasound/twins

WorldFengur - The Studbook of Origin for the Icelandic horse for supplying the statistics on Icelandic twins.