Wild Horses Get Pregnancy Check

As reported by the Bismarck Tribune's Lauren Donovan:

FRYBURG - The wild horse roundup at Theodore Roosevelt National Park near Medora Monday was anything but routine for the girls in the herd.
 
They went through a physical exam that included a pregnancy ultrasound and the extraction of fecal matter as part of a research project that could lead to the equine version of a pregnancy dipstick test.
They were well behaved about it, considering the intimate poking and prodding required.

The beautiful horses, manes flowing, were pushed out of the rugged park by helicopter. About 90 - better than half the park herd - were in the handling chutes north of Fryburg on the east side of the park by the end of the day.

The remainder will be rounded up today, possibly Wednesday, if needed.

Park superintendent Valerie Naylor said the horses' condition is good and the roundup was proceeding without a hitch.

They're rounded up every several years and some sold to keep the number down to the park's manageable level of between 60 and 90.

This year, the park will sell a number of young horses at an auction at 2 p.m. Friday at Stockmen's Livestock in Dickinson. The idea is to hopefully sell trainable horses, though there'll be some older ones in the mix of 90 or so that will be sold.

This roundup will make history for the park, since it's the first time a contraceptive as a means to hold down the herd numbers has been introduced.

About 25 of the mares were getting a contraceptive vaccine and another 25 were not, to compare how well the vaccine works over the next three to four years.

Christianne Magee, a veterinarian and doctorate degree candidate from Colorado State University, spent part of the day with a shoulder length latex glove on her hand and arm, ultra sounding the female horses through their rectum and extracting feces from pregnant mares.

She said the feces will be tested to see how much estrogen it contains compared to the same horse's blood sample.

The idea is that if feces can indicate pregnancy, park personnel will be able to collect it in the field by observing which horse it dropped from and thus be able to keep tabs on which mares are pregnant as part of the vaccine program.

Terry Nett, an associate dean of research at Colorado State, said using the fecal pregnancy test on horses would be fairly novel and the benefit from testing feces means they wouldn't have to be rounded up and handled for blood draws.

The fecal pregnancy test is very sensitive because the estrogen only measures in parts per billion, he said.

Magee and the three other veterinarians helping with the pregnancy tests and vaccination were finding plenty of pregnant mares in the group. In fact, it was harder to find mares that weren't pregnant - only four had come through the whole day. Naylor attributed that to good grazing and good health, the same for the parks' elk and bison herds.

(Reach reporter Lauren Donovan at 701-748-5511 or lauren@westriv.com.)

 Also watch a video on the horse roundup.