Why did my 4-year-old cat suddenly grow after we got a new kitten?

Hello. No, it is not normal for a cat to become taller this late in life. I strongly suggest that you have Toews examined. Although unlikely, I would like to make sure this is not feline acromegaly, a disease that results from chronic, excessive growth hormone secretion. Hope all is well & thanks for using Petco Pet Education Center, formerly Petcoach.

Your kitten should be growing in small amounts ever day. If you use a small kitchen scale, you can monitor his growth. If he is isn't growing, it could be that he isn't eating enough, intestinal parasites, or a congenital issue. At 4 weeks, he should start transitioning to kitten food. You can continue to mix kitten food with kitten milk replacer for another week or two. It may take time for your older cat to like the kitten. Kittens have a lot of energy and some older cats just don't want to deal with it! Make sure the older cat has her own place, and you need two separate litter boxes and food and water bowls.

Sometimes kittens are born as dwarf and will not grow much. This is a rare congenital disorder. More often kittens that do not thrive or grow normally have a congenital heart defect or a liver shunt. I suggest you have Foxy examined by a vet to rule out the latter problems, as there will be healt implications for her future life. Here is some information on those conditions: https://www2.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/portosystemic-shunt https://www2.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/congenital-heart-disorders

Gaining so much weight all of a sudden could be a sign of metabolic disease or an endocrine disease such as diabetes. She may feel ill and vulnerable and therefore tries to keep the other kitties away from her. Please take her to your vet ASAP for an exam and blood tests.

Although large-giant breeds such as maine coon, ragdoll, forest cat and bengal breeds commonly make 20lb or so in weight, it is rare for cats to be still growing and developing skeletally at 2-2.5years of age - it may be worth a check up by your vet to rule out any significant hormonal issues if he is growing in bone length as well as weight/body condition.

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! She could have a congenital issue like dwarfism or be a certain breed like a munchkin. There are genetic endocrine issues like hypothyroidism that can stunt growth but that is exceeding rare. It’s hard to say if it will affect her life span without knowing if her stunted growth is from a medical condition. Next time you take her to the Vet have them look in to it. I wish you the best!

If Silver is almost three years old now, she should be completely finished growing - so I would not expect her to get any bigger. Some cats do stay very petite in size; this isn't necessarily abnormal, as long as she seems healthy otherwise. If she is eating and drinking fine, active, and not overly skinny then I wouldn't worry - she may just be a small kitty :)