It seems to be a relatively
simple question. How
does the female of a
species “recognize” early on
that she is pregnant? In
humans, the embryo produces
human chorionic
gonadotropin (hCG, a peptide
hormone) soon after
conception, triggering a
waterfall of physiological
changes that allow the
mother to maintain the
pregnancy. In ruminants,
the embryo secretes large
quantities of a protein called
interferon tau. But the horse
is a mystery.
“Horses are one of the few species where we don’t understand how the female recognizes pregnancy,” said Dr. Jason Bruemmer, an Associate Professor of Animal Sciences and faculty member in the Animal Reproduction and Biotechnology Laboratory. “If we can figure that out, we might have a better chance of preventing early embryonic loss and enhancing reproductive outcomes.”
Understanding pregnancy recognition is just one area of equine reproduction in which Dr Bruemmer is focusing his research efforts. Early on in his career, and early means the age of 12, he worked at a thoroughbred breeding farm and veterinary clinic where his interest was piqued, though his start was modest.
“I had my first full-time job at the age
of 12 working at the farm mowing the
lawn and doing maintenance in the
breeding shed,” said Dr. Bruemmer, who
also was influenced by his grandfather,
who played polo, and his mother, an avid horsewoman who rode jumping horses.
“I began to develop an interest in equine
reproduction. It was a natural progression
that led me to my field of study.”
Dr. Bruemmer, who has a joint appointment in the Department of Animal Sciences and the Department of Biomedical Sciences, graduated with a bachelor’s degree in animal science and his master’s degree in physiology of reproduction from Texas A&M University. He went on to receive his PhD in reproductive physiology from New Mexico State University. He joined Colorado State University in 1996 and has since developed a dual-focus research program: semen preservation of the stallion, and cell differentiation with regards to maternal recognition and maintenance of pregnancy in the mare.
Using equine genetics, Dr. Bruemmer and his team help to better understand the genetic changes that occur when a mare becomes pregnant. They are work-ing to build the first equine gene chip to examine the 57,000 equine genes for up and down regulation, a first clue to genetic changes brought on by pregnancy. The project is funded through the Preservation for Equine Genetics Program (PEG).
“Conception itself is relatively efficient in mares, but a high number of embryos are lost in the first 18 days,” said Dr. Bruemmer. “Using ultrasound, at 12 days we can see the embryo. Ten days later, the foal is gone. For mares with great genetic value, those lost foals represent a significant reduction in their ability to produce offspring that will preserve their desirable genetic make-up.”
In his stallion work, Dr. Bruemmer is examining new ways to preserve semen including cryopreservation and the freezing of semen harvested from the epididymis. The techniques are particularly valuable when a stallion suffers a catastrophic injury or untimely death, or early castration in some, and owners wish to preserve the stallion’s genetic material for future generations. For horse owners, Dr. Bruemmer’s clinical and research work is offering exciting new avenues of assisted reproduction that will enhance a horse’s reproductive success.
Dr. Bruemmer’s work also has impact on the human medicine side, using the horse as a model to explore genetics and human reproduction. His interest in this area developed during a sabbatical at Harvard Medical School three years ago where he focused on reproductive physiology. Working alongside human reproductive specialists allowed Dr. Bruemmer to develop new ideas about the horse model and see first-hand human reproductive challenges.
While his clinical and research work are fulfilling, Dr. Bruemmer also enjoys a full teaching load including an equine reproduction practicum, foaling class, an introduction to equine science and continuing education courses for veterinarians, farm managers, and horse owners. He also is the faculty advisor for Colorado State University’s national champion polo team, a sport he continues to enjoy with the same passion he found early on working as a 12-year-old at a neighbor’s horse farm.
