A large percentage of foals that die shortly after birth do so because of a lack of oxygen; more foals die from respiratory problems than heart problems. Newborn foals that do not begin breathing spontaneously, are gasping, have a respiratory rate of less than 10 per minute, a heart rate less than 60 per minute, and are not responsive to stimulation all require resuscitation. As soon as the foal is born, the foal should be aggressively dried by rubbing and the foal's airway should be manually cleared. The nose should be manually cleared of fetal membranes and mucous. You can use a large bulb syringe if necessary or a 60cc syringe with rubber tubing on the end.
Although many have recommended holding foals upside down to help clear the airways, this is no longer recommended as holding the foal upside down has been shown to inhibit breathing. Also, slapping, shaking, and spanking the foal is not recommended. If bleeding from the umbilicus is substantial it is okay to clamp the cord but in general this is not recommended and tying off the cord is not a good idea. As far as breathing, if the foal is not breathing or the heart rate is below 60, artificial breathing is required. The best method for doing this is to pass a tube into the trachea through the nose or mouth and then resuscitate the foal with a breathing bag. This is not an easy procedure and in most cases, your vet will be required unless your vet has instructed you on this procedure and you have the equipment. It is a good idea to have an inexpensive stethoscope around because if the foal's heart rate is below 60 beats per minute or if the breathing rate is less than 10 breaths per minute, your vet should be called.