Breeding

How old can a horse breed? Most mares remain productive until their mid-to-late teens, with some producing foals into their early twenties. Stallions generally stay fertile much longer and may continue breeding into their mid-twenties or beyond. But breeding age isn’t determined by a number alone. Fertility depends on reproductive health, breeding history, genetics, and …

How often do mares go into heat? A mare usually cycles about every 21 days during the breeding season, and the actual heat period lasts about 5 to 7 days. Early-spring cycles can be longer and less predictable before they settle into a regular rhythm. Fillies typically start cycling between 12 and 24 months old, …