Is anything connected to the EGC, which is connected at the service to the grounded conductor, normally within reach of the animals? If not, bonding the floor isn't really accomplishing all that much. Equipotential bonding is to assure the floor is at same potential as anything else they may come in contact with that is conductive, if electrical system grounding conductor isn't introduced to anything they can touch they are already sort of on an island electrical potential wise.
This is part of why it is even more critical in dairies. Old dairies had some troubles - if anything the piping taking milk away was the main issue, otherwise they not normally in contact with much of anything that is somehow connected to the EGC but now milking areas are often loaded with electrical equipment. NEC wrote the rules in a one size fits all manner though.
