The Big Bang Theory alum and her husband Karl Cook adopted the animal as a rescue
Kaley Cuoco - Style
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Kaley Cuoco is paying tribute to her dwarf pony, Fiona.

In a heartbreaking Instagram post on Monday, the Big Bang Theory alum, 34, shared that the dwarf pony she and husband Karl Cook previously adopted as a rescue had passed away Sunday from health complications the animal had been struggling with all her life.

“After a very short time together, our precious dwarf pony rescue Fiona, passed away last night. she came to us & @pomponioranch @mrtankcook in such terrible shape, we were thrilled we got any time with her at all,” Cuoco began in her post, sharing several professional portraits of the pony taken shortly before her death.

The actress went on to caution fans that while dwarf ponies may look cute, they often suffer from health issues and “should not be bred this way.”

“Let me make this very clear.. there is a reason she was a rescue. We take on many of these dwarf ponies and it looks so cute and exciting that everyone wants one. It’s not,” she wrote. “They have severe medical issues and most have been completely mistreated and not taken care of.”

Cuoco continued, “Fiona was a prime example: she came to us malnourished, horrible feet, rotting teeth, she needed help to stand every morning and that’s just the beginning. These animals should not live this way and should not be bred this way. It’s WRONG.”

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“We did all we could but her small body could not survive. She no longer has to live in pain and she passed away covered in blankets surrounded with love,” she added, before thanking Cook, 29, and other animal advocates for helping take care of Fiona in her final days. “We will continue to save everything we can but know days like this will happen. ♥️ we love you princess Fiona!!”

Cuoco is well-known for her love of all things equine. She added to her family of horses by welcoming Bella and Poker Face in 2016 and adopting a dwarf mini horse named Shmooshy in 2017.

Last year, she told PEOPLE that her passion for horses eventually led her to meet now-husband Cook, a professional equestrian.

“I was already involved with horses, then we happened to meet at a horse show,” Cuoco said in August. “It was totally meant to be. We were pretty much a good match from the beginning.”

“We share so much love for animals — we love horses and we love the sport,” she continued, explaining that seeing Cook — whom she married Cook in 2018 — interact with horses helped strengthen their bond.

“I think anyone who works with animals has to have a kind soul,” Cuoco said. “It’s almost like he’s the horse whisperer. He is just wonderful with them. It’s really beautiful to see that patience he has with them … he’s so gentle.”

Recently, Cuoco and Cook expanded their furry family by adopting Dumpy, a senior dog they had been fostering in their home amid the ongoing coronavirus (COVID-19) crisis.

“What a foster fail looks like 😛,” the star captioned a picture of her holding the pup with Cook on Saturday. “Dumpy Cook, you stole our hearts!!!! 😍🤩”