Are you trying to improve an existing stand? If so, it will be safe but not much new grass will survive. If it comes up the cattle will pull the young grass up before it establishes a good root system. Need to wait until next fall and find a way to keep the cows off until it is established a bit. Fall seeding works better most of the time in the southeast anyway.
I AM TRYING TO IMPROVE THE STAND, BUT WAS WONDERING IF SAFE TO FERT W/TRIPLE 10 AND THEN SEED WITH THE CATTLE RUNNING ABOUT. I KNOW IT WOULD BE IDEAL TO KEEP THEM OFF BUT LIKE I SAID I AM SPACE LIMITED.
I would try to get the fertilizer on BEFORE the rain lets up. The rain will was it into the soil, you will lose very little to volatilization and the cattle will be less likely to get nitrate poisoning. You might want to use an atv with a pull behind spreader even in the rain as long as you cover the hopper. Good luck.