I would agree with both that some electrolytes, and some corid would be a good preventative. Another thing that I usually do with a calf I know little/nothing about is to get some probiotic paste or powder and give it to them to get the bacteria in their gut tract up and working.
Regardless, if I buy a calf at an auction for any reason, I will give it at least one dose of colostrum. You don't know how old it is, and although the experts say the window for absorption of the antibodies is 24 hours, there is proof that the action of the colostrum being thicker also helps to get the gut tract to working better. So, no matter how old the calf MIGHT be, they get a bottle of colostrum when they get here unless they have come off a dairy directly that I know starts their calves off right.
Since you don't know what this calf did/didn't have, I might be inclined to go with a medicated milk replacer, but you will have to have a VFD for that, thru your vet. And I do not feed medicated milk replacer as a rule.