It probably alludes to an occupation, dairyman or such; but it might be complimentary, to someone who was the "creme de la creme." In Arabic there is a given name that literally means butter, but metaphorically means someone special. German influence on Polish and Czech, yes, but it works the other way too, especially with surnames. A lot of surnames that originate in Germany east of the Elbe are Slavic in origin. Andy mentions the Sorbs, one of several Slavic tribes absorbed into the German nation. There are still some thousands of people in Eastern Germany whose first language is Sorbian or Slavonian.