jewish law required field to have a 'sabbath' just as man did, you could plant a field 6 years out of 7, on the seventh year, it had a 'sabbatical'-- and was given a rest.

sabbaticals were required for other things too...like cows, and goats, and sheep the were used for milk and for edible young.

cows need to 'freshen' to give milk --(ie, they have to bear a calf every 2 year or so)-- after 6 calfs-- a cow had to be 'given a rest'-- and allowed to go a year with out having a calf. (which is really almost impossible, since few cows would live to be 15 or 16 years old (2 years before first calving, and 6 calved (each takes 9 months, just like a human) and 2 years of giving milk...

but it might have been applied to sheep (sheep milk is also collected for cheese and consuption) and goats...

How long do sheep live in captivity Dr Bill (or Capfka?) i love how sheep look, but really know very little about them (compared to cows--and i only know a smidgeon about cows..)