Racing is a big industry and a lot of money changes hands, in the US alone it is a "sport" worth $10 billion. Unfortunately, those nonhuman animals are not more than commodities in this game, even less than cars in a race. They "filled with fuel", and not even “repaired” when damage, and when there is no way they can "make” more money they are3 thrown away.

Animals in races turned into junkies by their trainers and veterinarians, who provide drugs to keep horses on the track even when they could not race anymore.
Commonly used drugs such as Lasix (furosemide) and Bute (phenylbutazone) and other pain relievers, numb pain, but do not treat the injuries that cause it.
Horses are forced to race with hairline fractures that, without drugs, would be too painful to run on, and the punters and trainers will lose money.
Humans force the animals, like some punch-drunk fighter, to make just one more round.

Obviously, those horses suffer from injuries and chronic lameness; but it does not matter to anyone as long as the money continues to flow.

Centuries of selective genetic pairing breeding many horses are born with fragile bodies. They run 45 miles per hour, weigh 1,000 pounds, and have ankles as big as yours and mine; the thoroughbred horse is a genetic freak creature. He runs too fast, his frame is too large, and his legs are far too small.

These horses lack fully developed bone structure, and are more likely to suffer injury. They develop acute lameness and often break a leg in the race. This is because their skeletal and muscular systems have not fully developed leading to shin soreness, which is as a consequence of the cartilage plate in the shaft of the leg bone undergoing too much strain which causes a tear in the periosteum layer around the bone leading to haemorrhage, acute lameness and scar tissue. Their body is feeble.

Magnificent, delicate, yet powerful adolescent animals forced to endure on-going and developing injuries at any given time – a perpetual destruction.

Breeders train and race horses at age of two, when they are just very young adolescents. Horses are herd animals with strong social behavioral needs and prefer to play and enjoy the companionship of their own. But like every other sort of exploitation this natural behaviour denied from them. They have no actual contact with fellow horses.

Apart from minimal exercise in the morning and the race, they are kept more than 20 hours a day in a small stall in dark, dingy stables, stalled separate from each other. They develop neurotic stereotypic behaviors, similar to those animals, which seen in factory farmed and circuses, such as wood chewing, box walking (round and round the stall), wind sucking (grasping an object with the teeth and sucking in air), or weaving (swaying the head, neck and forequarters from side to side).
They have no access to forage such as hay, straw bedding, and visual contact with other horses, in other words, they do not have the opportunities to express their natural behaviour.

Stereotypies are repetitive, invariant behaviors with no obvious goal or function; it is a horse lunatic asylum.

During the race, the jockeys are beating the horses with the whip and screaming and yelling on him, particularly when approaching the finish, they send the horses into a state of fright and frenzy.
And of course, the operators will tell you "they love the race".

Ninety percent of horses in race have lung bleeds and breathing difficulty, due to the excessive exertion demanded of them in the rigorous training and the race. Eighty-nine percents of the horses on races had deep, bleeding stomach ulcers within 8 weeks of starting race preparation ulcers.
In the US, 94% of the horses in races had one or more lesions in the stomach lining. However, of the horses who had raced within the previous 2 months, 100% of them had ulcers. When horses continue to race, their ulcers tend to get worse.
Apart from the stress of racing, the major reason for the ulcers is intermittent feeding. Horses are fed only at certain times, there is nothing to neutralize the acid and it damages the stomach lining.

The vets are not trying to heal the horses from every problem. The industry invests in many experiments on such horses, very painful and stressing experiments. Horses who considered as non-profitable are exposed to deadly viruses. In UK alone 10 million euro are invested a year.

Except of flat race, there is a jump race.
There are two types of jump racing, hurdles, and steeplechases. In hurdles, horses jump lightweight frame 'fences' with brush tops, whereas in steeplechases horses jump a number of higher, more solid obstacles. Jump races are generally long, tiring events. Hurdles are usually around 2800-3200 meters, while steeplechases are commonly 3200-3600 meters. Some races are even reaching 5,500 meters.

As an example of how tiring these races are for horses, the Great Eastern Steeplechase forces horses to run for almost 5km while also jumping 24 fences. Under this pressure, horses easily make mistakes that cost them their lives.

Deaths occur very often and increase every season.
Horses are large, heavy animals and when they fall, they crash to the ground with considerable impact. They suffer an extremely pain as the result of a fall, even if there is no serious or long-term damage.

In jump racing, the rhythm of the horses' gallop on the flat is interrupted by having to take off over the jumps, around 10 times in the average race, as many as 20 or more times in the longer races.
When horses are bunched up on the approach to a jump, this can make it more difficult to take off accurately and can lead to error or even a 'pile-up' if one or more horses fall or falter when clearing the jumps. Muscle fatigue, especially in long races, increases the danger of a horse making a mistake when taking a jump.

The bones of horses contain a spongy, honeycomb section, which is designed to act as a shock absorber. This structure is necessary because large stresses are placed on the legs.

When galloping at speed the force on the lead foreleg as it hits the ground is 1.7 times the body weight of the horse; the force is considerably greater when landing after a jump. Some of the shock of the hooves hitting the ground is absorbed by the spongy bone, which is compressed in the process.
A bone becomes weaker in the course of a race as a result of this micro-crushing.
To break a normal cannon bone at the start of a race it takes about 16,000 foot-pounds of force, but the amount of micro-crushing which can take place in a race can reduce this force to about 9000 pounds.

When a horse breaks a leg or shoulder the bones may 'explode' into many pieces, making it impossible for a vet to "repair" them, and even when recovery is possible, it is unlikely the horse will be able to race again. The cost of restoring a horse to full fitness is expensive, not necessarily successful and usually deemed uneconomic.

Consequently, horses' injuries get worse. Horses that suffer severe injuries as a result of drug induced racing, or failing to win races are sold to slaughterhouses, a more profitable venture for breeders than euthanasia, where operators sell the horse's flesh overseas for human consumption, or provide horsemeat to glue factories.

The long cramped ride to the slaughterhouse without painkillers, in unfit trailers (with low roof) is a great suffer for those horses.

The "winner" horses are confined in small crate after a year and a half on the racetracks for artificial mating.
The unwanted, rejected and "failed" horses: Most, and we are referring to millions, are sent to become a raw material for glue, pet food and fertilizer. Some are sent to Korea, USA, Japan, and other countries where racing "standards" are lower. But they will certainly be killed long before their natural day after living a life of agony.

Horses who end up pulling carriages through city streets are "breakdowns" from racing tracks. Standard breeds are often trained to race by being tethered to the back of a truck that drives increasingly faster, so carriage horse operators consider these horses "street savvy". But standard breeds are much smaller and lighter than traditional "draft horses" and are not accustomed to pulling heavy loads. Carriage horses are exposed to bitter cold and scorching heat. Horses work in temperature of nine degrees Fahrenheit, well below freezing. In summer months, horses suffering from dehydration or heat stress can die in just a few hours. Of course, horses are not comfortable among cars and trucks; therefore suffer from many accidents and injuries, horses which becoming "spooked" in traffic have caused even deaths. The smoke and exhaust fumes from urban traffic are dangerous for horses. Horses showed enormous lung damage, the same kind of damage you would expect from a heavy smoker. Carriage horses are constantly walking and standing on hard streets, lameness and hoof deterioration are inevitable in carriage horses. The problems are worsened by the inexperience of the gross majority of the owners and drivers, who are either incapable of recognizing lameness or are unwilling to suffer financial loss by removing a horse from service for a few days. Horses of course fasten with harnesses, a horrible situation. Sometimes the straps are so loose that they rub and chafe the horse's skin, or they so tightly they pinch. Conditions for carriage horses are not much better when the horses are off the streets. Raids on carriage horse stables have exposed stalls with no hay or other bedding, stall floors covered with urine and manure, poor ventilation in the stables, and horses who had no free access to water. Many stables have stacked floors--like parking garages--with steep ramps leading from one floor to the next. The floors in one stable were so rotten; they often gave way under the weight of the horses, repeatedly causing animals to break their legs.