The growth period is the most important stage in a cat’s life. Not only does she learn her future behaviors, but her body is molded into her eventual shape and size. Many factors influence growth and good nutrition plays a major role.

Growth in the cat takes 8-12 months, depending on sex and size of the breed(s). The larger the cat, the longer it will take to reach her adult weight. Since males are usually larger, he will take longer to reach his adult weight. By the time a kitten reaches her adult weight, she will have multiplied her birth weight by 40-50 times.

Factors specific to the kitten:
1. Breed – Like the majority of living species, the bigger the breed, the longer the growth period.
2. Sex – The make has a higher growth potential than the female and his growth takes several weeks longer. He will therefore be heavier then the female.
3. Genes – The sire and dame contribute equally to the kitten’s genetic code. Size, corpulence and any morphological feature can influence growth.
4. Hormones – Certain hormones synthesized by the kitten direct her growth. Early neutering or spraying does not affect the ultimate size (height, bone structure, musculature) of the adult cat; this is determined by genetics. However, neutering or spraying does affect weight gain and fat deposition. This is why I do not like to see cats gets “fixed” before 1 year old if possible. Research shows that within 48 hours of neutering or spraying, kittens will eat more and may experience rapid weight gain. This behavior can lead to obesity and many other health concerns.
5. Nutrition – Between the fourth and twelfth week of life, the immunity transferred to the kitten in her mother’s first milk (colostrum) gradually wanes. At the same time, her own immune defenses are not yet fully functional. Specific nutrient during this period can help protect your kitten against infectious diseases. In addition, as her muscular and skeletal systems continue to develop, she has very high energy requirements.

Factors specific to environment:
1. Hygiene – Poor hygiene at birth will affect the mother’s health and the litter will suffer on account of it.
2. Stress – Growth takes place, as in all young animals during sleep. Although after two months, the kitten needs less time for sleeping, the quality of her sleep plays a very important role.

Source: Pondview Veterinary Clinic