It should have grown back mab , i cut mine about 4 times a year and it always grows back ok . Maybe they just grazed it out ?
Have seen it used a few times on calves .
First time i was working on a farm in 78 , old style farm , grew all his own animal feed , kept sheep , dairy cattle , beef and a couple of pigs each year.
Well anyway , the calves were kept in small outbuildings , 6 or so to a shed , 6 sheds . One lot got the squits and within 24 hours they all had them . The farmer just told me to cut a barrowload of comfrey , lay it on a clean bit of yard and walk on it for 10 minutes , then put some in all the hay racks . This i did and they all went for it instantly . That evening none had the squits , less than 4 hours after eating the comfrey .
Did similar on other farms i worked on , all had big patches of comfrey near the sheds .
From memory it worked everytime .