If he adds any fat for burger it is probably beef suet and not enough for sausage, probably 20%, for sausage you need at least 30% I grind and make my own but if you want to use what you get from the butcher either grind up some pork butt or fat back or buy ground pork and add that to it. Experiment till you see what works or just tell your butcher to add more pork for you.