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    Doctor Scott Bennett filled a test tube with about seven milliliters of a nutrient-rich solution, dropped in the embryo and carefully taped the test tube near his armpit. It was a zebra embryo, a two-millimeter speck of life. Ideally, it’d be in the uterus of a horse — that’s right, a horse — within an hour. Body heat, that was second best.

    It was a spring day, 1983. Who knew Bennett, an equine veterinarian, and Bill Foster, a veterinarian at the Louisville Zoo, would use a filter and a microscope to successfully extract an embryo from a sedated zebra mare on their first go? They sure didn’t. They’d had their big idea over cocktails one evening after working together on a birth at an Arabian horse farm in Oldham County: transplant an embryo from an exotic equine (a zebra) and into a domestic equine (a horse) to test whether such a surrogacy could result in a healthy birth. If it worked, it would be a first. And it could allow future zebra mares to produce as many as nine to 12 embryos in one year, unburdened by that whole yearlong pregnancy marathon. If surrogates carried all those embryos, Foster thought, they could produce “a small herd of siblings.” What a way to punch back at population decline. The mom and pop zebras (named Gimpy and Cajan) involved in Foster and Bennett’s experiment were Grant’s zebras, from the plains of Africa. They’re not endangered, but Foster and Bennett knew that if this worked, a more threatened species, like mountain zebras or wild equines from Asia, could take advantage of their discovery.

    So here was Bennett with an embryo taped to him, in need of a uterus, stat. 

    He started making calls, to this farm and that friend. Got a mare that’s fertile? In heat this past week? Seven hours and several phone calls later, Bennett found Kelly, an older buckskin quarter horse he was familiar with, who was about 26 years old at the time. “(If) she just smelled semen, she got pregnant,” Bennett says to me with a laugh.

    Kelly’s owner told him the mare was in heat recently. Bennett’s response: “I’ll take her.”

    “What is this for?” the woman wondered.

    “Don’t ask,” he replied. 

     

    The zebra named E.Q. (short for Equueles, a constellation that in Latin means “little horse”) could’ve been just another zebra born to zebra parents at the zoo. But this was the ’80s, a time of growing environmental concern. Scientists were striving to find ways to increase populations of threatened and endangered animals. Many zoos stepped up to the cause. Steve Taylor, the Louisville Zoo’s assistant director of conservation, education and collection, says that, in the ’80s, zoos saw their role “as an Ark.”

    The concept of embryo transfer wasn’t new at the time, even between species. In the early ’80s, the embryo of an Asian guar (a bison-type animal) that was placed in a domestic cow grew into a guar calf at the Bronx Zoo. In 1975, the embryo of a Welsh mountain pony was produced in England, transported to Poland in a rabbit (repeat: rabbit) and then transferred to a recipient mare of the same species. But a full-blooded wild equine birthed from a domestic one? That had never happend before.

    At a kitchen island in the home of Kelly’s owner, Bennett and Foster set up a lab: microscope, incubator, pipette to, essentially, turkey-baste Kelly. As Bennett recalls it, they backed her up to open French doors, wrapped her tail, cleaned her up and implanted the zebra embryo. About three weeks later, Bennett returned to perform an ultrasound. There it was: a glob of fluid, no heartbeat or definition yet. He turned to Kelly’s owner to share the news.

    “It’s a zebra,” he said.

    Kelly’s owner, an Irish woman who has since died, hadn’t yet been told about the species swap. Bennett remembers her murmuring, “Well, bloody hell.”

     

    On May 17, 1984, the day of E.Q.’s delivery, photographers and reporters huddled in a barn at Bennett’s Equine Services clinic located in Shelby County. (The exact location wasn’t shared with the public due to death threats from individuals who disapproved of meddling with nature.) Zebra mares usually give birth after about 340 days, but Kelly was at day 366 and her amniotic fluid was becoming toxic with E.Q.’s urine and waste. Foster and Bennett decided to induce labor. Bennett’s gloved hand reached “elbow deep” into the birth canal to help E.Q., who’d gotten twisted. Bennett toyed with his audience. “Is this the giraffe or the zebra?” he said, rattling reporters slow to catch the joke. A couple of Bennett’s friends remember him being knotted up — a “hog on ice,” according to one — nervous that a stallion may have actually impregnated Kelly, an unplanned pre-zebra-embryo rendezvous that would lead to a horse being birthed before a waiting press.

    More than that, the moment felt massive, like the outcome was not simply about the fate of wild equines. If it worked, it would be a cushion to fall upon, an ambitious offering to the planet — let us help create what we destroy.

    After a few minutes, at about eight in the morning, Kelly’s water broke and a tiny hoof announcing a black-and-white leg popped out. “It has stripes!” Bennett cheered. Using a thin, flexible chain and a tool that looks like a wire loop, Bennett gently tugged the 60-pound zebra foal into the spotlight. A reporter for an international wire agency filed a story that newspapers in Canada, Los Angeles, Chicago and even China picked up. (“Horse of a different color,” read the headline of a short piece in the New York Daily News.) Kelly licked and nuzzled the gangly creature as if it were her own, unaware or unburdened by their absence of shared genes. (At least one witness to the birth swore Kelly gave a momentary puzzled look at her offspring.) Kelly nursed him and stayed by his side for roughly six months, first at Bennett’s clinic, then on exhibit at the Louisville Zoo. 

    Some 35 years later, Bennett and Foster both describe E.Q. as a “highlight” of their careers. Foster recently retired from the Birmingham Zoo and Bennett remains busy with his practice. E.Q., who ultimately wound up at the Houston Zoo and died there in 1999, will always be the first wild equine born to a domestic mare — and remains, for now, the only. The same experiment in England a few months later in 1984 ended in a stillbirth.

    Science has progressed. Cloning animals. Frozen embryos and stem cells. The greater priority is the salvation of ecosystems, not individual species. Still, Duane Kramer, a scientist who has run the Reproductive Sciences Laboratory at Texas A&M University for decades, applauds Foster and Bennett’s achievement. For years Kramer used E.Q. in lectures on conservation, even hung a poster of the zebra and Kelly in his office. And E.Q. is occasionally referenced in journals related to veterinary medicine and reproductive science. “It was very important at that time,” Kramer says. “I don’t know of anybody trying to conserve zebras at the current time, but it’s comforting to know (surrogacy) is there if needed.”

    This originally appeared in the September 2019 issue of Louisville Magazine under the headline “A Horse Births a Zebra.” To subscribe to Louisville Magazineclick here. To find us on newsstands, click here.

    Cover photo: E.Q. and Kelly, courtesy of the Louisville Zoo

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