I have registered LaMancha and MiniMancha Dairy goats. I have not tested ph yet as I haven't used the milk for my consumption yet. I'm just anticipating, LOL Yes the older does do tend to stabilize sooner than the new young moms. Also, the colostrum levels are certainly different for each doe. I am actually waiting for new grass before I start cheese, it seems to help the milk stabilize as well as add a spring freshness to the milk. I found that the quality of feed and the health of the herd has as much as anything to do with the taste and quality of the milk in my goats. I only feed the best quality alfalfa and timothy, good grains, and my pasture is virtually weed free, so there is not much chance of off tasting milk. The health of the goat is usually the reason for off tasting milk. proper mineral and clean water is vital. There is , however a subtle difference in the taste of each breed, as well as different balances of Milk fat, protein, etc...