Tie stalls and parlours are two very different aspects of dairy farming.
A tie stall refers to a type of housing in a barn. There are other approaches to housing for dairy cattle, such as free stall and loose housing. These decisions are made by each farmer as per their business plan and management approach in caring for their animals. However, the National Code of Practice for the Care and Handling of Dairy Cattle must be observed to ensure that each cow is comfortable, healthy and happy in whatever housing method is chosen.
A parlour is usually an elevated platform which the cows walk onto to be milked. It is the only one of the ways cows get milked. Again, there are a variety of types of milking systems, but that is a decision that each farmer will make that is best for their operation.