I have experience with burnt hooves, rather than frozen ones but the same principles would apply, and it is with sheep rather than cattle, but hooves are hooves.
We had a wildfire through 90% of 2700 acres and lost about 700 sheep and very fortunately only one calf out of 260 head of cattle (cows are obviously less flamable than sheep). About 40 odd head of expensive rams also got burnt badly, about 10 dead and others with 3rd degree burns. At an average replacement value of $1500 a head they were worth trying to save.
The good thing is that the calf is still small and light. It is harder with heavier animals. Also if she is only affected in one foot and is currently totally sound on the other three she should cope. If she is only loosing one claw and the other is OK she should be even better.
The bad news - it can be a lot of work if you are otherwise busy.
I have a long series of photographs of the burnt sheeps feet we treated over the last 14 months. I mean to write up and put online the case study and our thoughts on treatment one of these days - when life gets back to normal after the fire - which it has not yet (have a drought on top of a burnt out farm at the moment) There was not much online on how to save the animals, and plenty of advice and pressure from the govt vets to shoot them.
So - treatment:
I HIGHLY RECCOMEND A CHEAP CONSULT WITH THIS GUY WHO SPECIALISES IN HORSES BUT WORKED WITH ME WITH SHEEP. READ HIS WEBSITE AND CASE STUDIES ON DAMAGED FEET IN HORSES, HIS ATTITUDE IS AMAZING. He has excellent approaches and principles and is excellent with bandaging.http://stepaheadfarm.com
Keep the quality of the nutrition up and keep her in as calm and comfortable and socially happy condition as you can as soon as you can after injury. Her mother is feeding her but make sure she is getting all she needs and a little more. Keep both mum and baby calm and happy. Give them a mineral lick. We found that in the first few days after severe burns a low stress environment with company and good nutrition and shelter made the difference between life and death and healing and not (and hooves falling off and not). She is with her mum so this means keep mum happy.
Even if a hoof falls off it WILL regrow. The problem is keeping the hoof structures alive and reducing damage to them while the hoof does regrow, which with the sheep took about 9 months before the hoof was grown back enough to do some of its job.
If the hooves are going to come off then what your task really is is keeping the tender healing tissues clean. BIg Hint : If the hoof is coming off use the hoof itself as a dressing and cover for as long as you possibly can. Work out some sort of binding and dressing that is quick and cost effective. You can use the sloughing hoof over the end of the bone until granulating tissue grows to big to fit any more. If the hoof comes off you will need to put a soft pad under the bone. In sheep we used neoprene sheets and cut of squares and taped them to the foot with stretchy adhesive bandage. A calf is heavier and thick neoprene, or double thickness should do it.
If the hoof comes off and the bone is exposed and dries out the bone will die. If it dies it might hang around for ages but eventually fall out. If you can keep the blood supply going to the pedal bones while the hoof re-grows you can have a normal foot structure after. There will be a balancing act between the foot getting wet and stinky and wrapped up too long and well padded, and not enough padding, more airflow, drier and less stinky but too much pressure on the bone with no hoof. Ideal is frequent dressing changes and cleans - you will have to work out what frequency that is for you. If you can get a hoof boot, like a horse hoof boot but the size for the calf, that might save you a fortune in bandages and mean fast and cheap dressing changes which would be ideal.
If the pedal bone comes out it does not mean the animal has to die, it just will not be as sound or good an outcome. As another poster said they know of a footless young cow that runs just fine. If her hoof structures are not very good then as she got big and older and heavier there might be a problem and you might want to restrict her nutrition to restrict her weight but that is a long time from now.
Here is a case study of a lost hoof on a horsehttp://stepaheadfarm.com/Case151.html
The animal will let you know if it needs to die. You dont have to kill it now because it might be in pain later - you can worry about that later. The question is do you have the time, which you can also find out later.
I am happy to answer more questions - I have to get back to work now.
Again I highly recommend Dr Jolly at Stepahead farms http://stepaheadfarm.com
What you are really dealing with (trying to prevent) is necrotic avascular bone of the final bone in the leghttp://www.stepaheadfarm.com/AvascularNecroticBone.html
Again I will say you are trying to prevent this bone from dying of damage or drying while the hoof grows back.
Here is our blog I havent put anything on in a year because I have been too busy and stressed