Ridgetop
Herd Master
My friend Erick told me that Anatolians (and possibly other LGD breeds) only bark as a warning. If the predator ignores the warning they don't waste their effort barking, they will just try to kill it. Probably why your LGDs didn't bark. Why bark at the cat - they coud already see it wasn't scared by barking. They were probably saving their energy for the confrontation.They never barked. They just watched him, which made me curious because they are vocal dogs.
Unlike dogs, wild predators will not willing engage in a fight with serious LGDs, unless they are starving. Wild predators know that any injury can result in death for them - either infection, unable to hunt and so starve, etc. Usually barking by LGDs will keep the predator out, but if it ignores their warnings and comes in you won't hear a sound from your LGDs. Maybe shrieks of pain from the predator but often just a dead predator in the morning.
We have White Dorpers. We like their calm temperaments. A friend who raised black headed Dorpers for over 20 years said the black headed Dorpers were wild and crazy. In your situation, if you have a lot of open acreage with a lot of predators, the black head Dorpers being wilder and spookier may work better for you.