What are these rated for (WLL) with a cow hitch?

Generally a knot can reduce the strength of a rope by up to 30%. That being said working load limits can can be a 1 to 5 ratio or sometimes a 1 to 8 ratio. So when you take this 1 to 8 ratio you are looking at a working load limit of about 2,700 lbs. This could include the reduction of the knot but if you didn't and you wanted to take off an additional 30% you would be looking at about 2,000 lbs for the working load limit when you are being super conservative.