I use this mash to get high doses of vitamin C into cows and horses who have issues that I want to help them clear up. Can be used for goats and sheep too.
Dissolve in about a quart of warm water:
1/4 cup apple cider vinegar with the mother
60-100 grams of vitamin C powder. I use ascorbic acid powder usually.
1000 mg of niacinamide powder
1/8 cup or so of livestock minerals
Add a couple scoops of alfalfa pellets.
Add water just over the pellets.
Mix it all together.
Let it sit until the pellets soak up most of the water.
Pour it into their feeder. Sometimes they don't like it at first and will just take a few bites. By the second or third day they'll eat it all down. You can feed it a couple times a day if needed.
The amount of vitamin C you give any animal depends on the seriousness of the issue you are helping them resolve. The most serious issues (a cow on the brink of dying) can warrant doses of 1 gram per lb of animal per day or more. A cow in shock should get 100 grams at a time, perhaps giving that every 15-30 minutes, until the cow comes out of shock and is back on its feet. It's better to overdo it, as not providing adequate amounts will not resolve symptoms.
Normally, a healthy cow makes internally about 25 grams a day. If the cow weighed only 150lb, that would adjust to about 5 grams a day. A 150lb goat makes about 10 grams a day, so a cow isn't a great producer of vitamin C. A goat can up its production to 100 grams a day under stress. If you give a cow 60 grams a day, then you are tripling the dose over what they normally produce, so that might be a good dose for supporting calving for treating edema, mild mastitis, skin issues, herpes, warts, or a hoof infection. Something like pneumonia, I would shoot for 50-100grams an hour each day until the cow stops coughing and is breathing well.
A cow that has a chronic symptom or infection may have something wrong internally that's not reparable. The case of Clara comes to mind. Clara had frequent hoof infections and mild mastitis. She was also a grumpy and slightly aggressive with other cows. The infections would resolve as long as I was supplementing her with ascorbate daily. Once the infections cleared, I would stop supplementing her, but in a few weeks they would return and I would have to supplement her again. We eventually harvested her, and when we eviscerated her, we noticed internal problems...organs out of place and part of one lung was protruding through her diaphragm. These looked like birth defects or early injuries that healed. So Clara's internal problems were causing ongoing stress that depleted her ascorbate and made her susceptible to chronic infections.