I shouldn't worry about nutrient loss. There are few micronutrients in butter anyway and those that there are are fat-soluble anyway and so you aren't losing anything in the removal of the milk solids.

Nor should the heating be a worry. For one thing, ghee is necessarily produced over a low heat, otherwise you'd burn the butter. In any cooking use of the butter, you'll be heating it far more. I don't know whether vitamin K is particularly heat sensitive, but Chris Masterjohn in his epic vitamin K2 article says:

I have yet to see any hard data on cooking losses, but everything I have read indicates that vitamin K is very heat-stable (though it can apparently incur losses from exposure to light).

As to the butyric acid or conjugated linoleic acid, both of these are fats, which can't be destroyed just by heating.

To quote from a comment I made on that thread (Grass Vs Hay fed butter): "According to that article, if you are using raw butter and want to preserve all its vitamins (unnecessary if all you're going to use your ghee for is frying food), you might want to keep the temperature below 150, or possibly 115 Fahrenheit (respectively 65.5 and 46.11 °C)."

I am a ghee maker in Northern California. Using too much heat to clarify the butter is very destructive to the outcome. Ghee should be kept at a low temperature (under 118 degrees), which is very difficult and time consuming, so many ghee companies do not do that. In fact, many sources explain that you should bring the butter to a boil. That not only damages antioxidants, enzymes begin to unfold at 119 degrees.

Since we are beginning to treat Alzheimer and dementia patients with ghee, even here in the West, because of the butyric acid in ghee which feeds nerve and brain tissue, and reverses the damaging affects of the disease, I do not believe that it is destroyed through the heating process. I intentionally keep my temperature extremely low while clarifying my organic ,grass fed, cultured butter because it is healthier and much better tasting. It also allows for a grainy texture, which is more valued medicinally. The low temp keeps the flavor in tact as well as the healing enzymes in the cultures. I then age the ghee for a minimum of a month - which further enhances the healing properties and the flavor.

Charaka Sambhita in an ancient text said: "Ten-year aged ghee is the miracle cure for any ailment". That is where I got the idea to age it (75 degrees constant). I don't know of anyone else aging ghee before it is sold. You can find me online.

Much love and happy ghee eating. ~Mama Sattva mamasattva.com

Does it matter if the cows were grain fed because I live in Panama where cows are grass-fed but my friend brought me ghee from th US.