Having checked the question on Pets.SE, you seem to want to know when it will be safe for rabbits to graze the treated area. As with all liquid lawn weedkillers, once the spray or solution has dried, it's safe for animals and children to use the lawn, though 24 hours elapse is safest. For grazing animals though, it is not safe if that is their only food source on a daily basis. Looking at the Q & A section for this product displayed on the link you provided, re-application can be made 3 weeks later, which strongly suggests a minimum of 3 weeks, but usually, the time elapse between treatment with a product of this nature and the grass itself being safe to consume is 6 weeks. It may be longer if the weather is very dry and the rate of grass growth is slow.
If you're still not sure, if you click on the Question and Answer tab lower down their page, you are able to post a question there directly to the manufacturer.