Yes, you can use Hay-Now Liquid Fertilizer after cutting. The product label states "If cutting, apply Hay-Now after every cutting with 2 to 3 inches of re-growth."
When applied correctly, Hay-Now Liquid Fertilizer will not damage your hay but should be applied when it is actively growing not after it has been cut. According to the product label, if cutting, apply Hay-Now after every cutting with 2 to 3 inches of regrowth.
Hay - Now is safe to apply while animals are present. If the animals are grazing in the areas being treated, per the label, apply Hay-Now every 30 to 45 days. Suggested application rate is 1 to 2 quarts diluted in 10-20 gallons of water per acre. For best results though, we would recommend to let the area completely dry so the soil can take the nutrients in before letting your animals back to the treated areas to graze.