If your cat is still vocalizing after being neutered, it could be due to a variety of reasons including residual hormones, pain or discomfort, psychological issues, pent-up energy, or even retaliatory behavior. Generally, cats recover from neutering within about a week, but this can vary depending on the individual cat and the care they receive post-surgery.

1. Residual Hormones:
After neutering, a cat's hormone levels gradually decrease, but some hormones may still remain. This can cause a neutered cat to continue displaying mating behaviors. Additionally, the cat may retain memories of being in heat, leading to similar behaviors for some time after the procedure.
2. Pain or Discomfort:
Post-surgery, your cat may experience pain or discomfort, which can lead to crying. Furthermore, if the cat doesn't receive enough attention and care after the operation, it might cry due to feelings of insecurity.
3. Psychological Issues:
Cats might develop psychological issues after surgery that cause them to cry. The surgery itself may induce anxiety or unease, leading to constant vocalization. Lack of social interaction and engagement after the procedure can also contribute to these problems.
4. Pent-up Energy:
Cats are naturally nocturnal creatures, and neutering won’t change that. They tend to sleep during the day while you're away and then become very active at night, often disturbing sleeping humans. If you don’t spend enough time playing with your cat, it might start vocalizing loudly to get your attention and prompt you to play.
5. Retaliatory Crying:
Some cats are quite vengeful. They might understand that you were the one who allowed the vet to take away something precious. Consequently, when you are sleeping peacefully, they might silently come to your side and start treading on you. If you wake up, they'll hide and start meowing loudly, as if scolding you for your actions.
How Long Does It Take for a Cat to Recover from Neutering?
Recovery time from neutering surgery varies depending on the cat’s sex and individual differences. Generally, most cats recover in about 7-10 days. Male cats typically recover quicker, within 5-7 days, while female cats might need about 7-15 days to fully recover.