After breeding mare should not be ridden for at least four weeks. This allows the embryo to start developing safely and gives the mare time to rest and recover as she is at the most uncertain time of her pregnancy in those 30 days. After first two weeks post breeding a vet can already confirm the pregnancy by ultrasound, although the embryo is still in a very sensitive phase at that time. It's only after one month that the mare can slowly start to exercise again, keeping in mind that the most important thing is for her to stay healthy throughout the pregnancy period and deliver a healthy foal.