So, my extended family owns a small cattle ranch. I don't know all of the details of the business, but I know that we have a herd of about 160 cows and that is considered pretty small. My thoughts are:
1) Buying calves sounds expensive. You definitely want to grow your herd yourself instead of having that cost every year. That is most of the purpose of having your own herd. Again, I don't know the specific details, but I know that my family keeps one or two bull calves every year without castrating them, and also keeps most of the cows for breeding purposes. The money comes from selling the remaining steers. Every once and awhile if an old cow is unable to produce, that is the one that will get butchered and be for the family to eat, since we don't mind if it's a bit tough
2) Like some people have said before, you get more of the profit if you package and sell it yourself. That is a good way to go for a smaller operation. My family actually isn't doing this, and I'm going to be trying to help them transition.
3) Growing some of your own feed is probably a good idea. You could try cutting down the size of your herd and using some of the land to grow a bit of feed to see if that helps bring down your costs.
All of that depends on your specific situation of course! I don't know anything about the market or practices where you're based.
I don't think I'll have the land/time to grow & spin my own fibers anytime soon, but I might still consider buying the course just because it sounds fascinating. Let me tell you, a LOT of people my age are becoming very enamored with the idea of cottage living. Admittedly for a lot of people it's more aesthetic than anything and most of us have no idea about the work involved. But there's definitely interest and if you can channel that into a real skill that could be very powerful. Also, with it being an online course with the ability to reach a global audience, I'd say you have a great chance of attracting people to your course.