Veterinary surgeon Peter Wright, 64, began working with world-famous vet and author Alfred Wight, who is better known by his pen name James Herriot, at a practice in Thirsk in 1982.
The practice moved to its current site in Thirsk in 1996 and it was named Skeldale Veterinary Centre, before the original became a tourist attraction called The World of James Herriot.
Animal lovers have been following the work of Mr Wright and his colleagues on The Yorkshire Vet since 2015 and on tonight’s episode it was revealed that he has left the practice, but will remain on the hit Channel 5 documentary.
Earlier this year, he moved to Grace Lane Vets in Kirkbymoorside, North Yorkshire, where there is less arable land in the surrounding area and more farmers with livestock in need of veterinary care.
Due to a significant drop in the number of dairy herds around Thirsk in recent years, Skeldale Veterinary Centre has become a practice that specialises in treating cats, dogs and other small animals. That meant Mr Wright had to decide whether he would remain there, move away so he could continue working with cows and other large farm animals or retire.
He told the Yorkshire Post: “I discussed it with my wife and I think she made the decision for me really, because I think I've still got some work left in me, as a Yorkshire farmer would put it.
“But also my wife said ‘I don’t want you under my feet all day long’ so the decision was made that I would find a mixed practice that would be willing to take me on, so I could continue doing what I’ve always done.”
He added: “Walking out for the last time, knowing that I was no longer going to be part of that practice was a very thought provoking moment really, and I must admit it did bring a lump to my throat.
“This is the end of an era for me. But at the same time, as one door closes, another opens and I have a new challenge to look forward to now, I can't dwell on the past.”
The father-of-two, who lives with his wife Lin in North Yorkshire, has fond memories of working at the practice and said he always had “the utmost respect” for his mentor Alf White.
“He was a lovely, lovely man. I never heard him raise his voice in anger and he was always there with a snippet of advice, if I needed it,” he said.
Mr Wight said many aspects of the profession have changed enormously over the last 40 years, as it has become less male-dominated and far more reliant on technology.
But he still strives to provide clients and patients with the same level of care and attention and follow the two rules he was taught as a young vet - always turn up cheerful and always perform a thorough examination.
He said he is still learning almost 40 years after he first qualified and is not planning to retire anytime soon, but admits that he has become “softer” in recent years.
“I find it increasingly difficult when I've got to give bad news. I don't find it easier, I find it harder,” he said.
“I've always been able to see the other person's point of view, and sometimes I put myself into the position of the clients who are receiving bad news.
“When I put an animal to sleep, I drive away thinking ‘for goodness sake that could’ve been me that has just lost an animal’. I know what it’s like because I've lost animals and they're almost part of the family.
“I think: how much misery have I left behind? Yes, I've done my job. But at the same time, it's quite upsetting and these emotions of sadness stay with me for longer.”
Mr Wight said he is enjoying his new job and relishing the challenge, even though he sometimes feels like "a new boy in the new school".
"I feel so welcome there. It's a lovely, friendly, welcoming practice. So in some ways it's a home away from home, but it is a new challenge," he said.
"I'm also still seeing quite a number of the farm clients that have always see so it's a perfect fit."
The Yorkshire Vet is shown on Channel 5 on Tuesdays at 8pm.