I have (2) dairy goats that are more like pets. I am new to goats and rather than call out the vet I want to make sure I'm not over reacting. They are both 2 1/2 yrs old, never bred, one is Alpine and the other is Alpine/Nubian mix. They seem to have enlarged teats and sacs (?) for lack of a better word. It doesn't look like an milk engorged udder. There are (2) separate sacs (?) with the attached teat. I know this sounds crazy but I'm trying to describe what I'm seeing!! Appetite good, no diarrhea, behavior normal. They are not up on their shots I guess because they are in my backyard and they sleep on the deck. (They are not in a barnyard environment) I feed them a large Folgers container of textured goat feed (between the two of them) in the a.m. and depending on the weather and grass or tree limbs I'll give them a section of hay (between the two of them) in the evening. I keep clean water available at all times. Are their teats/teat sac supposed to be enlarged?
Alpines and Nubian breed dairy does are prone to get precocious udders, especially when they get to maturity which is for these breeds at about 2 to 2 1/2 years of age. That means they have good dairy quality and even though they have not kidded any high protein feed can kick in their hormones to start creating milk/udder. If you do not plan to breed them I advise not giving them higher protein feed than 9%. Any "goat feed" generally is made for does in milk and has 14 to 18% protein, and I would expect this is causing the does to create their mammary systems. The "separate sacs/udder halves" are seen because the udder has not developed totally and that is normal. I would not give them any more of the goat feed you have them on - would check the label to see what the protein is. Use of a COB (corn, oats and barley) type grain, either wet (with molasses) or dry (without molasses) - this is available at most farm/feed stores. Are they a bit over conditioned/fat? You should be able to feel the ribs, backbones and the tailhead (either side where the tail attaches to the backbone) should be flattened, not sunken in or pushed out. Also, is their poop pelleted?
As an aside, a precocious udder generally does not hurt them health wise, you would just need to watch for mastitis.
Hope this helps - Donna