Oftentimes, actors need to negotiate some scary maneuver that they’re really not prepared for. That happened to Samuel West, who’s co-starring in PBS’ “All Creatures Great and Small,” which returns tonight.

As a veterinarian in the English countryside, West had to face a rearing horse that landed a few feet from him. “I haven’t really done any riding since ‘Hornblower,’” recalls West.

In that series he played a battalion commander astride his noble steed in the British Army. But that was 23 years ago.

West recalls, “Our Portuguese horse-master on that one had done a bit of matador training, so I said, ‘What’s the first rule about being a matador?’ And he said, ‘When the bull charges you, you have to tell yourself to keep your feet together.’ I said, ‘Why is that?’ He said, ‘Because they want to run away.’”

West says he knows the feeling. “So I gave myself that note in front of this rearing horse,” he continues. “I sent my girlfriend a wide‑angle picture of me with the horse above me and she said, ‘That looks exciting.’ I said, ‘Yes. I wanted to run away.’ And she said, ‘Oh, my God. That’s you! I thought that was a stunt man.’”

The popular series “All Creatures Great and Small’’ — back for Season 3 — is based on James Herriot’s books that are themselves the result of the author’s life as a country vet. So the actors — many of them city kids — matriculated in what they call “vet boot camp.”

Rachel Shenton, who plays the neighbor of a nearby farm, says she had some minor experience in the field, though in the first series she was tethered to a black bull as big as Texas.

“ ... We did two or three days with Andy Barrett, who’s now our on‑set vet. And we got to be on the farm and get sort of up-close-and-personal with the animals and ask all those questions,” she says.

“For me it was always just about feeling comfortable and natural. (My character) Helen grew up on the farm, was around livestock, cattle, from being a toddler. So as long as she felt comfortable and I felt comfortable, then that was kind of always my point of reference, sort of my operating point.”

For Nicholas Ralph, who plays the newcomer vet, this was not only his first time coping with animals, it’s his first acting role. That almost never happens, says Ralph. “I graduated drama school in Glasgow, and my first job, I was off to the Yorkshire Dales, on the train, looking at the stunning scenery.”

He was scared, he admits. “Healthy nerves, like anybody,” he says in his thick Scottish accent. “But once you got into it, I really did feel at home on that first day. I was really lucky as well because the first day was with Sam, and he didn’t really leave my side, and he was there to answer any question. And we had a lot of fun with the scenes. And they were very hard, but it was a great introduction, really, and you just kicked on from there. I felt very comfortable from the (start), thankfully.”

West agrees, “I think when you start any new job — especially one that has as much name recognition as this one — we are all beautifully nervous about: is it going to work? I think what we realized really quite quickly was that we had a wonderful ensemble and as much care was being taken of it as could possibly be. And from then on, it was just a pleasure.”

While West had to cope with a bucking horse, that is not the worst thing about acting with animals, he says. “I have got to vote for my worst animal,” he notes. “The old thing about, ‘Never work with children, animals or Denholm Elliott.’ I would say children and specifically cows. Cows are much, much harder to act with than anything else.

“They don’t like it if you move away from them. They like knowing where you are. So if you are standing next to a cow, and you have managed to get it on its mark, and then you continue the scene by walking away, as we had to do with a very funny scene ... that I really enjoyed, the cow goes, ‘Where is he? Where is he?’ and backs into you. And, in my case, steps on your foot.”

The books of James Herriot (a nom de plume for Alf Wight) have been adapted to the screen before. There was a 1975 film and the seven-season series that ran on PBS from 1978 to 1990.

Two years ago, producer Colin Callender decided to try again. Callender, who has helmed such projects as “Temple Grandin,” “Grey Gardens,” “The Spanish Princess” and “Howard’s End,” says he was hesitant at first to resurrect the story.

“I was a bit nervous at the beginning — because we were following in the shoes of another version with a number of beloved actors in it, and I felt there was a way to do the show that could sit side-by-side that and not be upstaged by it. And I think within minutes of the first episode, the audience bought hook, line, sinker every actor in every role in that household,” he says.