There's no good 'old school' Vets anymore. Ones which work hard, not afraid to get dirty and brutally honest. Like, if there is nothing he could do he would tell us to take it home and shoot it. Instead of pumping meds and giving false hope like many do today.
Anyway, no, our Vets are not open on a weekend either, they have emergency lines and if something happens which can't wait until monday you can bring it in to the clinic and it will cost you more.
One good thing is though, if you have established your Vet/client relationship (annual health visit) you can call in, tell them what problem you are having, they'd suggest a treatment plan and you can pick up the meds in a lock box behind the clinic after hours. That helps a lot.
But having a Vet come out......... phhht...... ya....... if the animal can stand on all 4 they want you to bring it in. No farm calls unless the animal is down, even then it's not a guarantee they will come out. We had an older cow down last year, about a month after she had calved, called the vet, explained, was told to send pictures of the cow and that was that. "Yeah come and pick up some meds" No Vet visit.
Plus, you have to do the math before involving the Vet, how much is it going to cost and how much is the animal worth.
We rarely used a Vet in all my years here, until the Animal Health and Prescription rule came in that a Vet has to make annual health visits in order for you to get meds. I thought back then, hey maybe it's not going to be so bad having a direct line to a Vet, but honestly the only thing which I see as a benefit now is that I can get the meds after hours through a phone call away.
Running cattle isn't a hobby industry, but hobby animals is where Vet's nowadays make their money. While we, out in the field, learn through trial and tribulations. =(