Not a fiber expert, nor a knitter, but my impression is both of the animals you name have a softer hair than sheep. Perhaps a function of the spinning process since I used to have a sheepskin rug and it was quite soft. I suppose either could be worsted as wool is, but without a market there's not likely to be a rush to produce such a material. Allergies would be an obvious reason to look for other fiber content, do you have another or just curiosity?
Bob