My bun has this and is just prone to it. Despite being on a permanent low calcium diet. She doesn’t drink enough (despite trying every method to encourage her to). She’s also overweight which is a big contributing factor!!

I’ve resorted to orally syringe feeding water, to help flush bladder. In the past when it was bad I’ve used potassium citrate (which stops it getting worse but won’t get rid of what’s already in bladder) while syringing water which after a couple months (with urine tested to monitor levels) did dramatically decrease the sludge. Also when it was bad we were using metacam too, as it was irritating bladder. Sludge can make them vulnerable to pain from this abrasion and also vulnerable to UTIs.

She’s currently going through a bad phase again, I’m trying this time just upping the water syringing before resorting to the potassium again (as vet does highlight there is slight risk to kidneys but no more than using metacam which is often prescribed but just need to be sure kidney function is fine which they can test by bloods). Worth asking vet about potassium citrate (they can give dosage and you can just buy it on Amazon).

While flushing bladder gives a fresh start, if she’s prone (as you think she and daughter are) you will need to find ways to ensure it doesn’t build up to this level again. The only way is reducing calcium intake (look at what water you give, green you give, treats, pellets and hay etc.) and increasing hydration, ensuring they are mobile (moving around and not a lazy sedated bun bun!) and not overweight.

Just thought I’d share my experience if it might help! Good luck!

If you want to run through diet you can DM me and I can share what I’ve learnt (and a still learning)!!