Animal anatomy, histology, pathological anatomy

Autopsy of equid carcasses
The order of equids includes herbivores, in which the axis of the limb passes through the third finger, covered with the hoof, which receives preferential development and determines the characteristics of the statolocomotor apparatus (skeleton, ligaments and skeletal muscles). Odd-toed ungulates have an odd number of toes - from one to five. These include mammals of the horse, rhinoceros and tapir families. The horse family has three genera: zebras, donkeys and horses. The latter genus includes horses (domestic horse, wild Przewalski's horse, etc.), Asian half-donkeys (kulans, onagers, etc.), as well as horses - hybrids obtained from crossing a donkey with a stallion, and mules - from crossing a horse with a donkey. In the process of development of horse breeding, three main types of horses were created (riding, draft and draft), within which there are over 200 breeds and breed groups.
Anatomical features of equids.In animals of the equine family, only the third finger is developed, and the second and fourth are represented by small so-called slate bones hidden under the skin. The tail is long and hairy. The hair on the body is relatively short (1–4 cm), on the forehead (bangs), in the mane and tail the hair is long, thick, as well as in the fetlock area (brush), and sometimes on the back surface of the metacarpus and metatarsus (fries) .
The stomach is simple, its volume ranges from 6 to 25 liters (on average 18 liters). At the entrance of the esophagus to the stomach, a ring-shaped muscle (cardial sphincter) is highly developed, making it difficult to vomit, the appearance of which indicates a serious illness of the stomach (rupture, etc.).
The ratio of body length to intestine is 1:10. The length of the intestine is 25–29 m. The volume of the small intestines is about 94 liters, and the highly developed large intestine is about 192 liters. Peyer's patches are located at a distance of 1 m from the pylorus of the stomach. Only in the ileum there are large plaques up to 20 cm long and 3–4 cm wide. The passage time of feed in the horse’s digestive tract is 90–100 hours.
The liver of a horse is brownish-red in color and accounts for 2.6–4% of body weight. The left lobe is divided by a deep notch into the left medial and left liberal. The caudate process extends from the caudate lobe. The gallbladder is absent.
The spleen is triangular in shape: its wide dorsal end forms the base, and its narrow ventral end forms the top of the organ. The length of the spleen is up to 30–35 cm, the relative weight is 0.2–0.3%.
The heart is located between the 3rd–7th ribs, 3/4 on the left side of the chest. 18 ribs, 18–19 thoracic vertebrae, 5–6 lumbar vertebrae, 18–20 caudal vertebrae.
The youngster reaches sexual maturity by 1.5 years, but they begin to use it for reproduction at 3 years. Growth ends by 5–6 years. The duration of pregnancy is about 11 months. The suckling period is 6–8 months. Life expectancy is 25 years, sometimes more than 40.