You can ask for anything, but it’s up to the practice what they are willing to do and it’s up to you whether you’ll make it a deal breaker or not. In my own experience working in rural clinics as a prevet and vet student (towns ranging from 800 to 12,000 people with a ~1hr service area 2+ hours from a major metro area) and from talking to my friend, call is usually shared equally among all the vets, so joining a larger practice may mean you’re on call less but the vets around here attend emergencies alone or you recruit your own help; it’s just not usually feasible for a clinic to pay a tech to be on call in addition to the vet (heck my friend doesn’t even have a consistent tech at all, it’s just the two vets, a receptionist, and a part time kid they call in when they really need help working calves). Often the only extra “pay” the large animal vet gets for call on top of the usual production is to keep the emergency fee, and they certainly aren’t going to want to split their $200 call fee (or whatever it is) with a tech. In my area, if you demanded someone go with you, quite frankly the small rural clinics wouldn’t be able to accomodate that. It’s already a difficult area of vet med to charge what we deserve, and doubling personnel costs for call makes an already poorly-performing service cost even less profitable. Plus then two staff members are tired the next day instead of just one. But it may be different in a different area, especially one that is a bit more affluent than rural Oklahoma.
Whether a clinic sees non-clients for emergencies is usually a clinic/ownership decision, not the decision of the associate.
On one hand, it’s an associates market right now so you can try to make whatever demands you want, but call is usually something that isn’t very flexible and it just a given/fact of life you have to deal with being a large animal practitioner. You definitely want to know their policies but I wouldn’t expect much negotiation power, especially not as a brand new, new grad hire. I was offered a mixed animal job before graduation with 50/50 on call and a salary that was almost half of what my small animal classmates were being offered. My friend split call 50/50 with her boss when she was hired too. She did eventually negotiate with him to drastically reduce her call once she had kids a couple years into her employment there. But she’d decided if he’d said no, she was gonna quit and switch to small animal because call wasn’t sustainable for her with her family. It became a deal breaker for her So he agreed because he needed to keep her as an associate. Not everyone will have that kind of negotiating power or be willing/able to do that.