How much can sisters and brothers can the horse have?

Horses can have multiple siblings, as they typically have a foal (young horse) once a year. A mare can produce several foals throughout her breeding life, which can range from 10 to 20 years. Therefore, a horse could potentially have numerous brothers and sisters, depending on the number of foals its mother has had. However, the actual number varies based on the mare's breeding frequency and the stallions used.