Lynx - Gemma's toenails dropped off after her spay. She's the one we almost lost when she rejected her interior sutures and developed a massive infection. About 2 weeks after that her toenails started to drop off. My vet thought she'd just caught them on something until she conveniently let one drop while my vet was watching. Dead tissue - dead nailbed. A total mystery.
But the good news is they are all growing back (she lost 5 of her 6 hindfoot nails - front feet were fine). It took a while - 2 only just started growing in the last month and I think her spay was well over 6 months ago. They are growing in very thick and stumpy.
She never showed any pain or difficulty in walking.
It will be interesting to see if it grows back.