Definitely get the California Mastitis Test, Hoegger should have it (I think it's like $16 but will last a really long time), and test once a month at the very least. It won't necessarily catch all bad bacteria, but it will let you know if you're dealing with an infection in the udder. It's the best, and most accurate mastitis test available. With goat milk, it can sometimes get a little gelled and not necessarily be an indicator of mastitis, but I have yet to see that with my girls.