Congested Udder or Scar Tissue or Mastitis?
Not the same!
Congested udder is not the same as mastitis and is not as serious, either. It is not an infection but rather an issue with the teat not allowing milk to flow. It often occurs when the doe produces so much milk so quickly that it becomes overly full. It is uncomfortable but is relatively easy to treat and fix.
If your doe has one of the teats with a very small stream or nothing coming out at all, it may be the keritin plug isn't clearing completely or she has a small calcium plug.
In both cases you want to keep milking her with some force. If you hold some pressure and wipe the teat with an alcohol soaked pad that will sometimes help disolve a plug. Others say getting some warm water in a cup and holding her teat in it will solve this. The plug comes out pretty easy and she may not have any problems afterwards.
It could also be congestion constricting the teat. This can feel like a little donut at the top of the teat.
Sometimes scar tissue forms around the teat canal. Also little threads of tissue called spiders can form across the canal, blocking it. Vets recommended re-opening the canal with a needle or inflator. They start with a 16 g needle. The next step is inserting a cannula (inflator). If you could not insert it, the orifice is too tight. Try with a thicker needle. All of this needs to be done in an extremely sterilized condition. If the thicker needle does not work, the Vet will bring a special tool to cut the scar off. This requires great experience so call your Vet.
First, before assuming the problem is a congested udder, run your Mastitis test. Take does temperature.
Mastitis in Goats
By Ronald J. Erskine, DVM, PhD, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University
...states Mastitis in Goats is more common in the later stages of lactation. This is partially because a of a higher proportion of epithelial cells in caprine milk than in bovine milk. As lactation progresses, shedding of epithelial cells into milk increases; thus, SCCs >1,000,000 cells/mL are common in uninfected does in late lactation. Proper milking procedures and good environmental sanitation are needed to reduce the prevalence and spread of infection. Chronically infected does should be culled, as should does with M mycoides infections and those that do not recover from M putrefaciens or M capricolum infections.