Where would you be getting the holstein bull calves? If you are getting them from the auction barn...oh my gosh!
You would have to be able to buy a whole bunch at once ...not just 2 or three...and have the facilities for them to make any money at all right off the get go. You have to remember that these calves are likely not to have had the benefit of colostrum. You have to give them shots when you get them home...and put in one big supply of probios. You have to have a vet that will give you an open prescription on whatever you might need. You have to remember that "dead" is written all over them.
I'm sorry...been there, done that. Holstein bull bottle babies are the most fickle calves in the world. And, they don't seem to grow out of it. At any time respiratory infections can set in. Why? 'Cause of the lack of colostrum.
Holstein bull calves from the sale barn, or heck, even from dairies, are jerked up and sold the minute they hit the ground.
If you are prepared to work your tail off...watch them like a hawk...keep an endless supply of medicine and electrolytes on hand...feed them 4 times a day instead of 2 when, not if, they scour, oh man.
Where do you live...that doesn't matter. If you live where it gets super hot in the summer, forget it. And, if you don't have enough land to rotate/move the pens, forget it. And if you think you can raise them in those little, tiny wood hutches forget it.
And, if you want to try it, please, please, please, don't sink too much money into it right off the get go. Start out with no more than 10...make sure you have pens that keep them separated and allow for them to be able to move around more than just a few steps...and can be moved to clean ground real often. Make sure that they can stay warm in the winter and real, real shaded in the summer. Jeez Louise, I could go on and on.
Alice