The horse's leg was broken, and for the horse, it was a nightmare disaster. Many people have the impression that horses with broken legs often face the consequences of being euthanized. Why is this so? This article will reveal the biological principles and consequences of a broken leg from a biological point of view. 
Horses are mammals and belong to the order Odd Ungulates. Their limbs, especially their legs, carry the weight of their whole body, and they also bear the impact of running, jumping, and other sports. Horses have complex leg structures, including bones, muscles, joints, blood vessels, and nerves. When a horse's leg breaks, it can affect the integrity of these structures, raising a range of biological questions. First, let's take a look at the biology that can arise after a horse leg breaks. Fracture healing is difficultHorses have a larger bone structure and a relatively slow healing process. When a horse's leg is broken, the healing process of the fracture site is greatly affected. First of all, due to the high bone density of horses, it is difficult to form a stable healing environment at the fracture site after fracture. Second, when the horse is running and walking, the broken bones may be displaced, making the healing process more difficult. In addition, horses' bones contain more calcium salts, and abnormal structures such as bone spurs and bone bridges are easy to form during the healing process, which further affects the healing effect. Joint damageWhen a horse's leg is broken, the joint can also be damaged. Joints are tissues that connect bones and are responsible for reducing friction and cushioning impacts during exercise. When the joints are damaged, the horse's ability to walk and run can be severely affected. In addition, joint damage can also lead to an inflammatory response, triggering diseases such as arthritis. Vascular and nerve damageWhen a horse's leg is broken, nearby blood vessels and nerves can also be damaged. Damage to blood vessels can lead to symptoms such as bleeding, hematoma, and even shock in severe cases. Nerve damage can cause paresthesias such as pain and numbness. These symptoms can affect the horse's quality of life and may even lead to death. Muscle damageWhen a horse's leg is broken, the muscles attached to the fracture site can also be damaged. Muscle damage can lead to muscle atrophy and decreased strength, affecting the horse's athletic ability. In severe cases, muscle damage can lead to muscle necrosis, further aggravating the horse's condition. 
Why, then, do horses often face the fate of being euthanized after breaking their legs? First of all, horses are large animals, and the medical resources and costs required for a broken leg are very high. Under modern medical conditions, although there are advanced methods, such as internal fixation, external support, etc., these methods often require long-term processes, and the effect is not guaranteed. It is a very heavy burden for horse owners to bear such a cost. Secondly, after a horse's leg is broken, the horse's athleticism will be seriously affected even after passing **. Horses are prairie animals, and it is in their nature to run and jump. Once the leg is injured, the horse's ability to survive will be greatly reduced. In the wild, such horses are likely to become targets for predators. In captivity, horses that lose their ability to exercise also require special care and feeding costs. Finally, after a horse's leg is broken, the horse's pain and psychological stress cannot be ignored. Horses are intelligent animals, and they are able to feel physical pain and discomfort. A broken leg not only affects their quality of life, but also causes them fear and anxiety. In this case, euthanasia becomes a more humane option. 
In summary, the biological principles and consequences of broken legs are multifaceted. From the difficulty of healing fractures, joint damage, vascular and nerve damage, muscle damage, etc., we have all seen serious problems that can arise after a broken leg in horses. In real life, the cost of a horse's broken leg, the horse's survivability, and psychological pressure also make euthanasia a common choice. I hope that through the popular science of this article, you can better understand the biological principles and practical dilemmas behind horse leg fractures.