I would love to have a family cow. I dream of having access to all that beautiful milk, cream, making my own cheeses...
Unfortunately, at this stage this is not practical at all for most families, including us. At the same time, milk is a major on-going household expense, as all my kids just LOVE milk. The adults in our household also use a fair amount in beverages and on our muesli.
We have been using powdered milk for some time now. Powdered milk is significantly cheaper than UHT milk, which again tends to be cheaper than fresh milk. However, it is worth shopping around a bit, as there are some big price differences depending on where you buy. The cheapest I have been able to find so far is the supermarket chain ALDI, where powdered milk currently costs $4.79 a kilo. The instructions say you should use 140g of powder to make one litre of milk which yields about 7 litres of milk per pack of milk powder. However, I find that there is no taste difference whether you use 120 or 140 grams, and as we drink a lot of milk, I just use a bit less powder and usually get around 8 litres from each bag of milk powder. That means I pay just under 60 cents per litre of milk. This is a significant saving for us as a family with a children who all love drinking milk.
I had tried using milk powder before and hated the taste. I hadn't realised then that there is a bit of a knack to mixing it up. I prefer to use my scales rather than relying on cups to to measure the amount of milk powder I need. Don't use a spoon to mix the powder with water, as that will result in lumpy milk. Instead, fill the right amount of milk powder into a one-litre bottle. Add enough water to make about half a litre of milk, put the lid on the bottle and shake until all powder has dissolved. Then add the remaining water to make up for one litre. By the way, cold water works better than hot water. If you mix the milk in the evening and leave the bottle in the fridge over night to settle and chill, there is no discernible difference in taste to other milk.
Unfortunately, I have not been able to find any comparative life-cycle study of powdered milk versus bottled "fresh" milk versus UHT carton milk so I am not sure how powdered milk stacks up with regard to its environmental credentials.
I do know that producing powdered milk requires a large amount of energy. If that energy was produced by using renewable energy such as solar or wind, this would not be such an issue. If the energy is produced by burning coal, then this is a significant contributor to greenhouse gas emissions.
On the other hand, powdered milk does not require refrigeration for storage and transport which saves a lot of energy. In addition, 1kg of powdered milk is roughly the equivalent of 7-8 litres of "standard" milk, resulting in a massive reduction in fuel used for transport. Powdered milk also requires far less packaging, which again translates to significant savings in resources and energy.
Taking all these considerations into account, there seems to be an environmental benefit to powdered milk. It is definitely kinder to the family budget.
However, if you know of a reputable life-cycle analysis of milk and milk products that proves me wrong, please let me know.