Never heard of a heifer being called a stripper in these parts.
In the days of handmilking cows each milker, who usualy milked around six cows, would be followed by another, who was known as a stipper who would strip [ie the cow] to ensure that it was completely milked out thus helping to prevent any disease developing in the beast.
When milking machines were invented, by Murchison of Kilmarnuck, the stripper would strip the four teats before the machine was attached thus ensuring that they were all fully functioning.
The late ??? Innes informed me that the famous Turra Coo was a three titter ie. it only produced milk from 3 tits---not the best beast to have in your byre.