When milking any kind of dairy animal, be it cow, goat or sheep, you want to make sure to keep up demand on that animal to continue producing milk. Generally with sheep and goats, milk production peaks around the 2 month of lactation and then it will generally begin to taper off. This decrease in milk production is a result of the decreasing demand from the kid or lamb for the mother to supply milk. Most lambs are naturally weaned by 2 or 3 months of age. So it is important to keep that demand on the ewe in order to continue getting an adequate supply from her. Now i will focus on non-dairy sheep as most dairy sheep should be giving around a quart a day through their 6 month lactation, non-dairy sheep will give significantly less and that amount also has a lot to do with how much you milk them. When milking sheep there is always the question of should I milk once or twice a day. With a full-sized dairy goat or cow, one can get away with milking once a day. Which should supply an adequate amount of milk for one's need but with non-dairy sheep it is almost essential to milk twice a day after the lambs are weaned. Doing this will keep the level of milk production from continually declining. There is not fighting nature sometimes though, and there will usually be a sharp decline in milk production after the first month.
My experience in milking sheep is exclusively from milking katahdins. I can tell you that during peak lactation times it is common to get 1 pint to 1 quart of milk per ewe per day. After they have peaked and milking twice a day, I have seen the production settle around 5-8 oz a day. They can keep producing at this level for a few months before you dry them off for breeding. When milking non-dairy sheep, it is also important not to skip days milking or do a once a day milk for a day or two because production will decline sharply and it will be difficult to come back to that level once it's lost. I was milking a ewe for about a week, once a day. I had bought her while she was already in milk. She was giving me about 12 oz a day. I skipped a day and she went down to 5 oz per day. I never got her back up to twelve when I started milking her twice a day everyday.
When you don't have access to dairy sheep, you can only get a little bit of sheep's milk at a time. It is so precious so it's best not wasted. Many people who milk sheep, do so to make cheese. It's takes a while to save up 2 gallons of milk, my minimum for cheesemaking, when you are getting 5+oz of sheep milk a day. One good thing about sheep's milk though is that it freezes well for later use because saving it in the refrigerator will have half your milk spoiled before you've even saved enough to make cheese. Sometimes it seems like a lot of work but in my experience places to buy sheep's milk are few and far between and when one does find them, it is much pricier than the cost you might put in to raising sheep and milking them at home. I've seen $14 for a half gallon in my area but there is also an upside to that if you have enough sheep to sell to others. It would be a pretty lucrative side business. Anyway. remember sheep's milk is precious, don't take it for granted when you have it because the well may quickly dry up leaving you with an empty pail.