Breeding a foal is full of uncertainty, but the staff at a US veterinary center probably did a double-take when a donkey mare in their care produced a foal with stripes.
Donkey jenny Jayla had been bought by Deanna and Tom Kohley, who run T&D Donkey Rescue in Liberal, Missouri. They drove 13 hours to an exotic game farm in Texas to pick up what they thought was a mammoth jenny. They were not deterred when it turned out that Jayla was a standard donkey: “We couldn’t leave her behind since we drove so far,” Deanna said.
They knew the 10-year-old was in foal, but the sire was unknown. A Grevy’s zebra stallion was a possibility, but given the rarity of such crosses because of the difference in chromosomes, it seemed unlikely.
To ensure the best chance for both mare and foal, the Kohleys sent Jayla to the Veterinary Health Center at Kansas State University in Manhattan, Kansas, to have her foal.
“We waited anxiously for over two weeks and then I received a phone call from Dr Laurie Beard saying ‘She has stripes!’ So we were very happy,” Deanna said.
Zyla is the first zebra hybrid at T&D Donkey Rescue.
A donkey typically has 62 chromosomes, inheriting 31 from each parent, and a zebra has 44, with 22 coming from each parent. Horses have 64 chromosomes. A foal born with a zebra father and a donkey mother is a “zonkey”, but if the breeding is the other way around, the offspring is known as a “zedonk”. Cases in the wild are rare but not unheard of; most are found in zoos.
Zyla and Jayla have come home from Kansas, and are both doing well, Deanna said.
Zyla is spending her days frolicking with other donkey youngsters, and despite their differences, she is getting along with her new friends very well, Deanna says. “She loves to run and kick up her heels. She is such a joy. She is handled throughout the day and is very smart. She just loves people and follows everyone around.”
In 2017, researchers in Italy looked at the genetic background of a foal born to a donkey mare and a zebra stallion. The zebroid foal was found to have 53 chromosomes in which a haploid set of 22 chromosomes came from the zebra and 31 came from the donkey. Haploid is the term used when a cell has half the usual number of chromosomes (one member of each pair), in this case in eggs or sperm produced in the ovaries or testicles through the process of meiosis for the purposes of sexual reproduction.
The most recent common ancestor of the modern equines lived from 4.0 to 4.5 million years ago. The lineage leading to asses (including the donkey) and zebras split off from the shared ancestor about 1.8 to 2 million years ago, according to several older reports. In 2018, the genome of the donkey was been sequenced, and this estimates the split between asses and zebras to 200,000 years earlier.
T&D Donkey Rescue, a 501c3 nonprofit organization, is home to nearly 100 rescued equines – mostly donkeys. The 100% volunteer-based organization is dedicated to abused, abandoned, neglected, and at-risk donkeys.