From birth to puberty:

• In the cow between birth and two months of age there is little growth of the udder.
• But between two months and the time of puberty (7-8 months), the mammary gland grows 3 ½ times faster than the body weight and reaches the peak pubertal development at 10 to 12 months age.
• The mammary gland does not grow much after this period until the animal becomes pregnant.