Chris Mortenson: Stress and Fertility

Interview with Chris Mortenson, PhD, Equine Specialist

Birds do it, bees do it, even horses and we do it. Becoming pregnant can be all too simple and, often times, all too difficult. A number of factors can make a difference. Equine physiologist Chris Mortenson is studying one factor, stress, and it turns out the same stresses that affect horses also can affect humans. Letís find out what Chris has learned.

For 2008 what weíve been working on here is, weíve been working out our mares six days a week and what weíve discovered this year is that the effects of exercise and the stress associated with it has a definite affect on the mares reproductive cycle.

And what does that mean to the breeding programs, itís a big industry? Right, right, right. I mean itís a multi-million, billion dollar industry every year. In some of these mares, really the high value high dollar mares that they use in an embryo transfer program and thatís where they breed them and collect the embryo and put it in a surrogate mare. They try to get as many babies out of that mare per year to increase; you know their income and make more money off it. And what weíre discovering is if they go ahead and still compete with these mares, and travel the shows, and go around the country while theyíre still breeding them it induces stress on the mare that has a definitive effect on her reproductive cycle.

Can this have any application to humans? Oh most definitely. If you really think about letís just say mammals, because weíre a mammal, sure, really between horses and possibly dogs and then humans, you know, those are the only three mammalian systems that you could really consider athletes, and then if you look at horses and humans, horses have what we call singleton, or they carry one baby at a time, very similar to human pregnancy. So we can draw correlations between whatís going on in horses and then take a look and see if we can draw conclusions in humans. I mean if you think of the stress response, you know, in the human body, or letís just say the horseís body, it still elicits different changes hormonally, that affect the entire body as it tries to maintain what we call homeostasis, and its balance. So any type of social stress, or exercise stress, or heat stress, or even nutritional stress, where youíre not getting enough calories every day, it still elicits several responses in the body that can have an affect on the reproductive system.

It sounds like these are exciting times for you and for the horse farm. Oh definitely, I mean you can see our new beautiful exerciser and Clemsonís built us these nice pens, and itís just weíre really excited, and thrilled, not only in the research that weíre finding but where weíre going from here.

Well I look forward to coming out and seeing how things are going in the future. Great. Thanks for your time. Thanks Peter. Take care. Chris Mortenson and his horses show us that while the most compelling desires many of us have, the desire to make a family, requires us to reduce the stress in our lives. Makes sense to me, in fact it makes ìhorse sense.î This is Peter Kent for Science and Society.