Around Christmas time I am always offered a drink by my clients,and each time I have to refuse,One won't hurt they say,but when you are working with animals,and driving from client to client ,one is one to many in my book,and if you are not sure of how much you can drink,ie half pint or one pint, one short or two,and each persons tollerances to alcahol can differ from the next.
All in all if you are driving, no matter what time of year,DON'T DRINK