No, it wasn't. The laws are quite explicit about what "abuse" means, and if you take a gander at most laws (including Washington state's circa 2000 or so) in the context of animals it usually explicitly refers to physical harm (for example, mutilation) or improper living conditions. Charging them under Washington's existing abuse laws would've required the animal to be physically injured, which it wasn't. It's quite literally why they had to pass a new law.
I don't know why I have to explain this, but:
1) Sexual abuse can occur without physical harm or injury.
No, it wasn't. The laws are quite explicit about what "abuse" means, and if you take a gander at most laws (including Washington state's circa 2000 or so) in the context of animals it usually explicitly refers to physical harm (for example, mutilation) or improper living conditions. Charging them under Washington's existing abuse laws would've required the animal to be physically injured, which it wasn't. It's quite literally why they had to pass a new law.
I don't know why I have to explain this, but:
1) Sexual abuse can occur without physical harm or injury.
2) Beastiality is sexual abuse.