A horse race is a competitive event in which horses are harnessed to jockeys for a race on a specific course. The race may be a flat or steeplechase (over fences). Prize money may be awarded to first, second and third finishers. Many races are graded; the higher the grade, the greater the prize money. A race’s grade is determined by a set of rules, which are generally agreed to by racing associations and governing bodies worldwide. The rules are based on the age, sex, birthplace, previous performance, and training of the horses and riders.

Historically, races have been conducted over a variety of distances, from a few yards to four miles. Shorter races are referred to as sprints, while longer races are called routes in the United States or stayers in Europe. Fast acceleration is often required to win a sprint; however, in long-distance races, stamina is more important.

In the United States, horse racing is regulated by state governments. The state racing authority typically has a number of employees that manage the business, conduct inspections and regulate the safety of the horses. The authority may also oversee a horse breeding program. In addition, the state racing authority often has a veterinary department that ensures the safety of the horses and enforces the rules.

A horse race begins when a jockey mounts a tethered horse and leads it around the track in a prescribed order of jumping each hurdle (if present). The rider must complete the course without making any unplanned stops or falls to be declared the winner of the race. The rider must also complete the race within a set time or be disqualified.

As the sport of horse racing grew, national and international race governing authorities established a set of rules for determining the winner of a race. These rules, referred to as the standardization of races, were intended to make the results of each race more predictable for gamblers and the press. The standardization of races also allowed a race’s handicapper to assign weights to each horse that would enable horses with different records to compete on equal terms.

When a horse is competing in a race, it is normally injected with Lasix, which has the effect of preventing pulmonary bleeding. The drug’s diuretic function causes the horse to release epic amounts of urine–twenty or thirty pounds worth. For decades, virtually every thoroughbred horse was given Lasix prior to a race. This was done to prevent pulmonary bleeding, which hard running causes in many horses.