Star-Foals

Despite the fact that since the late 2100s cheap electrically powered all terrain vehicles of both tracked and legged varieties have been available, many frontier worlds still choose to use animals to move people and small quantities of goods between settlements, especially in remote areas. Most common is a collection of genetically engineered horses known as star-foals.
The precursors to star-foals were first bred in the closing years of the 2000s. Conditions on Chiron, the newfound colony around Alpha Centauri B, were harsh and as the early colonists started to push out from the initial landing sites, new farms were spreading out faster than new roads. Some colonists had brought various animals from Earth, and horses quickly began to populate the alien prairie. Over generations, farmers bred them to better withstand the slightly higher gravity and take advantage of the higher oxygen content in the atmosphere.
In 2092, Space Horse LLC was founded on Earth. There were sixteen extrasolar colonies by 2092 and they quickly managed find buyers for specially bred horses, oxen and other working animals designed to withstand their own local conditions. Sales continued to grow until the secession of the Altair Federation in 2096, as their primary off-world research site which they had spent trillions of dollars building to move away from the dying Earth was suddenly behind a trade blockade. By the time the Altair Federation became the Independent Planet Protection Pact in 2109, Space Horse was dead.
This didn’t stop the development of specialised breeds for different planets, but it did slow research into more general approaches. It still took years, even with then advanced genetic manipulation techniques to produce a species tailored to a new colony and so colonies with environments closer to existing ones had a much easier time of it.
Everything changed in 2132 when a then unknown biotech company calling itself Star Helix unveiled a proprietary process by which they could adapt virtually any non-human terrestrial animal to thrive in a new environment given relatively little information. Their first major product was the star-foal. They had produced roughly one hundred breeds of horse covering all the major parameters by which a habitable planet could differ from Earth. A batch of one thousand embryos and the equipment to mature them into fully grown horses cost less than a single cargo hovercraft.
For almost sixty years, the Star Helix logo was ubiquitous across human space. Their horses, or descendants of their horses, provided huge amounts of manual labour on frontier settlements across human space. Despite this, and despite what 23rd century holomedia would tell you, the aesthetic of the Old West never really came back.
Unfortunately for Star Helix in 2186, Ankaa Heavy Industries released the Iron Shire line of legged all-terrain vehicles. With high density fuel cells that could last several days between refuelling, a projected fifty year service life and a one tonne carrying capacity, an Iron Shire might cost five to ten times the price of a star-helix draft horse but it could carry five times as much, never tired and lasted three to four times longer. Just to add insult to injury, the hydrogen fuel they took was also a lot cheaper than feedstock and AHI would happily provide a new colony with a solar powered hydrogen generator for free with a purchase of ten or more Iron Shires.
Within a decade there were dozens of manufacturers of cheap all-terrain vehicles and newer colonies tended to favour mechanised labour over horses. Even with the best genetic modification money could buy a draft horse still took two to three years to mature, meaning a batch of colonists needed to bring adult horses with them, which only added to the expense. After nearly a century of non-stop growth to the interstellar horse population, in 2203 the number of living horses peaked for the last time.
That being said, there were still those who rejected the mechanised alternatives. Be it as a rejection of technology more broadly, the utility of a horses as a source of protein or a desire to remain attached to an element of human history, many frontier societies continued to use horses and other beasts of burden to this day. Star Helix still exists, but their business has shifted towards other species and more generally vat grown meat and other biological products.