You have a model not set for Iray, for example the pets by MostDigitalCreations or the basic Hivewire House Cat (if you don't have a good texture for it). When you try to render the model in Iray you get this:
Ugly, isn't it? Well, there's something you can do to make it look better.
First of all you need to have Octane installed in Daz: if you don't have it you can follow the instructions in this link.
Then we can start. Load the cat in the scene (or the pet you chose from MostDigital). Now select Surfaces pane:
In the Surfaces pane be sure that the cat is selected in the Editor:
Still in Surfaces pane, go to Presets, open Shaders, then open Octane:
In Octane options select Hair:
Now click Ork Hair-Shine C.
Back to the Editor, set Base Mixing - Weighted:
Done. Now you can render in Iray or you can try Octane. In Iray now you get this:
Much better, isn't it? This procedure works also for hair props not set for Iray render. Final comparison: