[SallyintNorth]

Anke, your calcs look about right to me.

My milking, skimming and butter-making is all by hand and rough-and-ready, plus the Jersey milk is very very rich and creamy, of course.  I take 2-2.5 L of milk a day, mostly skim the cream off for butter, make butter every other day or so in a jam jar.  

I don't know if you've had a go at making butter from your goats' milk yet?  If not, I would urge you to have an experimental go and see just how much you like the butter - and what you feel about the amount of work it is - before splashing out on equipment.  Even with a seperator and an electric churn, there's still a lot of washing and working the butter to get the buttermilk and then the water out and stop it getting an 'off' taint very quickly.  Because I only make enough for a day or two (for two of us) at a time, it doesn't really have a chance to get very 'off', but if you are making nearly a pound a day you will need it properly cleaned (or all be happy to have that hint of sourness in your butter.)

I didn't ever expect that I would make all our butter, I thought it would be special occasions only.  But we both love it so much we couldn't bear to go back to shop-bought manufactured pale tasteless stuff!  I even use it for cooking - I can't bring myself to pick up the shop-bought manufactured pale tasteless stuff and sully a cake with it.  

I will need to get a supply of well-cleaned stuff stocked up in the freezer for lambing, though...