By: Brittany Bevis
Now that foaling season is well underway and preparations are being made for the next breeding season, we thought it important to touch on a topic that receives little attention. While some might think of a recipient mare as simply a “baby making machine,” the mare you choose to carry your foal might have more of an effect on its future than you realize.
Although a recipient mare contributes no physical DNA to the foal it carries, knowing the mare’s background is an important consideration to make before breeding, says Amy Gumz of Gumz Farms.
“Most importantly, [you want to know] if she is a good mother, easy to foal, hormone deficient, etc.,” Gumz says. “However, personality traits are great to know as well, but often secondary or lower on the list as most recipients are often picked by how they match up to the mare’s reproductive cycle and size of the mare.”
“She is more than just a uterus and milk machine. The care and handling of the recipient is seen in the foal’s behavior and physical well-being. If she is a ‘nasty’ mare, you will often see those ‘nasty’ traits in your foal, unless it is weaned quite early.”
In her own personal experience, Gumz has even seen recipient mares pass along unusual traits to their foals after birth.
“We once had a recipient that had a very odd sounding whinny,” she says. “Her foal, although no DNA shared, had the same whinny. Bad and good behaviors are shared with the foal, especially the longer the foal stays on the recipient’s side.”
“Foals can learn to weave, be hard to catch, and be aggressive to other horses and people. These are all learned behaviors and they will certainly learn from their substitute mothers.”
Moreover, a badly mannered or ill-handled recipient mare can cause even more problems by making it hard to do things like proper foal imprinting, halter breaking, or administering medication.
When looking at this topic from a scientific standpoint, David B. Scofield, DVM, MS, DACT at Select Breeders Services in Maryland makes several important points about the interesting field of Epigenetics and proper recipient mare nutrition. In its simplest form, Epigenetics is the study of changes in gene activity that are not caused by changes to DNA. It all has to do with the transcriptional potential of a cell.
“You have a normal embryo that started from a sperm and egg from donor animals,” Scofield says. “It has DNA from the mom and DNA from the dad in that embryo. When they take that embryo and put it into a different environment, in the recipient mare, the mare exerts control over the baby, not only in luminal secretions of the uterus, what actually nourishes the early embryo, but more importantly the mare has a different temperature and environment which can cause different representations of the DNA.”
“DNA is bound and coiled in a normal double helix, and it has bonds and molecules that hold it all together. When placed in a different environment, there are different ways for that DNA to be expressed. There is a lot of theory in there, but you can’t tell me that when you take a living organism and put it into a different environment that it doesn’t have an effect [on that organism].”
Further expansion on this topic touches on the idea of fetal programming. If a human fetus is affected by the health and nutrition of its mother during pregnancy, then certainly the same must be true for horses and other animals.
“I think the recipient’s nutrition is extremely important,” he says. “All of our recipients are fed not only tested hay to make sure they have enough protein, but, instead of over-supplementing with grain, we feed ration balancers. Poor mare nutrition can have an effect on things like OCD incidence.”
“You can think of it as having a glass half full. If the mare is half full of nutrition and trace minerals, she needs to get that glass full before she can start to pull off resources for the baby. If you start supplementing a mare after she is already in foal, or during her third trimester, you’re already behind the eight ball. A mare can’t replenish her own resources from the past eleven months in the last three months of pregnancy.”
Finally, Scofield echoes what Gumz had to say about a recipient mare’s personality affecting the foal she carries.
“If you have a recipient mare that’s unmanageable, that you can’t catch, or that’s very protective of the foal, it makes it hard to work on the baby if there is something you need to treat like contracted tendons or diarrhea,” he says. “Safety, for me, is very key. My mares live out in a field. If I can’t go out and put a halter on them, I don’t keep them. Because of my handling facility, I can’t take a mare that’s hard to handle or that you can’t catch.”
In areas of the country where a large amount of breeding takes place, large herds of recipient mares are often handled more like cattle than horses. Although that’s a concession many have to make, due to the nature of the fast-paced breeding industry, we would be remiss to think there won’t be any effect on the foals they carry, later down the line.