Pig anatomy


In most anatomical features, the structure of the pig is similar to the human body. And at the same time, the bulk of the cultured breeds retained the biological features inherent in wild animals. This is a high fecundity, the presence of strong teeth and four-fingered limbs with hoofs, a small head, ending in a bare and flat patch, as well as a voluminous body that can grow quickly and store a large amount of fat.

Head with an extended snout

As with the vast majority of other mammals, the piglet’s body has basic sections consisting of various tissues, bones and muscles. According to their form, they determine the exterior of the animal and its belonging to one or another breed.

A carcass of a healthy and non-defective pig is divided into:

  • head;
  • neck;
  • trunk;
  • limbs.

The head has an interesting structure. In addition to the cranium, in which the brain is located, there is a facial or muzzle.

The pig's muzzle is conventionally divided into the forehead, ears, teeth, as well as the nose and penny.

It should immediately be explained why the pig has a long snout. This is due to the peculiarities of getting food in the wild conditions, which we will discuss below.

Due to the fact that wild pigs throughout their history dug the ground in search of food, at the end of the nose they formed a flat penny with an excellent sense of smell. It has a dense structure, although it is sensitive.

Piglets' ears consist of cartilage tissue and, in most cases, hang freely, covering hearing organs.

Piglets' brains are very well developed, and pigs are considered intelligent animals that understand the commands of the breeder.

Strong teeth and long fangs

In wild pigs, as a result of natural selection, the shape of the head has changed, and the snout has extended. The muzzle of domestic breeds of pigs may be short or elongated. It depends on their exterior and orientation on the consumption of various feeds.

Domestic piglets regularly receive high-calorie feed, and wild animals need to constantly obtain food, including worms, small rodents and plant roots, rummaging to search for them in the ground. This explains why the pig has an elongated snout.

Like a wild, domestic pig has a well-developed oral apparatus, where there are up to 44 strong teeth. They are very strong and allow you to chew even the toughest food.

Pig's teeth can even crack nuts with very dense skin. It should be especially noted the presence of four canines, which in adult boars can reach a length of 5-10 cm and differ significantly in structure from other teeth.

The main growth of the canines in the pig begins after the animals reach three years of age, and they grow longer in the boar than in the sow.

The muzzle of the pig smoothly passes into the neck, on which the jugular gutter area is distinguished. Here are the aorta and jugular veins that provide blood supply to the brain, and the meat of this part is extremely tender and highly valued by gourmets.

Limbs with a pair of hooves

The musculoskeletal system in representatives of all pig breeds has a similar anatomical structure. It consists of axial and peripheral sections. The basis is the skeletal structure, which should hold the carcass of an adult animal, reaching 200-300 kg of live weight. To the bone structures, which are described in detail in the article "The skeleton of a pig," attached the muscles of pigs. These units are also especially appreciated by farmers engaged in industrial livestock production.

In pigs of any breed there are four four-fingered limbs, the structure of which is slightly different depending on whether the front legs or the rear. The anterior ones have metacarpus, wrist, forearm, elbow and shoulder. The back is divided into metatarsus, heel, shin, knee and thigh.

Two middle fingers on all legs of a pig during natural selection were transformed into claws (hence the name hoofed animals), and the two side fingers practically do not participate in walking, but they increase the stability of a pig when it moves on an uneven surface.

Piglets' hard claws are constantly erased while walking, growing from the inside due to the formation of a crumb.

Features of the constitution of the body

The constitution and stats of pigs (parts of the body) may differ significantly depending on the breeds.

So, wild pigs belong to the rough constitution. In professional pig breeding, meat and bacon breeds are considered to be representatives of the gentle type. Meat-greasy pigs have a dense constitution, and sebaceous - loose.

Each become a pig has its main characteristics, differing from each other in size, development of a particular muscle group, the presence of a thick fat layer. For example, depending on the constitution, the limbs of an animal may have a greater or lesser length, the presence of elastic muscles or swollen fat.

Separately, it should be noted representatives of the herbivorous breed of the Vietnamese visrubury pigs, differing in relatively small size and belly hanging almost to the ground.

The anatomy of a boar is almost the same as a pig. The only exceptions are larger body sizes, powerful breasts, the presence of the male reproductive system, as well as canines, which are much longer than other teeth.

Skin and skin

In the body of any mammal, epithelial, connective, muscular and nervous tissues are isolated, each of which plays an important role in the physiological processes occurring in the body of a pig.

Epithelial tissue is represented by the skin, which protects wild and domestic pigs from cold, heat and other environmental factors. Sebaceous and sweat glands regulate heat transfer. The skin has bristles that protect the body from damage. The same task is performed by the epidermis, a constantly exfoliating layer of dead skin.

The dermis or live skin of a pig is saturated with blood vessels and endings of nerve cells that increase its sensitivity.

Under the skin is loose connective tissue, in which fats or spare substances accumulate. This structure was called fat.

The skin is called pig skin, taken together with bristles and subcutaneous tissue. It can be used for the manufacture of footwear and clothing, as well as, with appropriate processing, in the food industry.

Skin glands of animals

The skin of the pig has a complex structure. It consists of sweat, sebaceous and mammary glands, hooves and underfoot crumbs, stubble and piglet.

Especially it is necessary to dwell on the mammary glands of the animal, providing feeding offspring. Depending on how many nipples a pig has, they are able to produce different amounts of milk. The sow productivity depends on it. An ideal pregnant sow can produce for two farms per year up to 28-30 piglets. The best is the presence of a female udder with 12 well-developed nipples, which produce 70-90 kg of milk per lactation period.

Certain localization on the body of the animal allows you to select the chest, abdominal and inguinal nipples, and in the inguinal area of ​​milk produced the least. The main task of the mammary gland is the formation of milk, which the sow fattens piglets that do not have teeth in the first days after farrowing, and are not able to absorb solid food.

The sebaceous glands provide protection to the pig's body from the cold, and the sweat secretes fluid, evaporating, it cools the entire surface of the animal's body.

Smart pigs with a developed nervous system

The pig's nervous system is represented by the brain and spinal cord, as well as nerve cells scattered throughout the body.

The brain consists of two hemispheres with a large number of convolutions. Due to the large amount of marrow, pigs are very intelligent animals. They are easy to train and quickly remember the commands, after walking they always return to their trough.

A piglet left unattended can leave the new pigsty, trying to return to the sow if he was always in the barn near his mother. There is a case when such a fugitive was found at a distance of about 60 km from his new place of residence.

The sense organs in pigs are not equally developed. Due to the presence of small, narrow-set eyes, their vision is binocular (they see the object with both eyes) and is weak. On the contrary, hearing is very sharp. Even signals that are not heard by the human ear are transmitted to the brain.

Pigs of any breeds have a very delicate sense of smell and even faint smells of food. Due to the sensitive scent, pigs of some breeds (Vietnamese vislobryushie) can distinguish poisonous plants from useful ones. And the ability to find truffles made animals an assistant to people in the search for these extremely expensive mushrooms.

Omnivorous animals with a strong digestive tract

The digestive system of the pig is very similar to the human digestive tract. It consists of the oral cavity, pharynx and esophagus, through which the feed enters the stomach. Food is digested in the small and large intestine, and in the rectum the body absorbs water and nutrients.

Thanks to the human structure of the digestive system, pigs can easily digest both vegetable and animal food. Waste is excreted from the body through the anus. In the article "The similarity of human organisms and pigs" find and other interesting information.

During the day, an adult pig is able to eat up to 6-8 kg of various feeds, and the amount of water consumed can reach up to 25 liters per day, resulting in about 3 kg of fecal matter. The waste products are systematically removed from the body, and the amount of manure produced by one pig per year is more than 1 ton.

Features of the intestine and liver

The mouth of the piglet includes upper and lower lips, cheeks and tongue, as well as a hard and soft palate, tonsils and mouth. For chewing and softening food, the animal uses gums with teeth and salivary glands that secrete a special alkaline liquid.

The pharynx and esophagus of the pig have a hollow structure and ensure the delivery of chewed food to the stomach, where splitting occurs under the influence of the acidic environment and enzymes.

The division of the small intestine of a piglet is divided into the duodenal, jejunum and ileum, in which the villi are located on the internal cavity. They increase the absorbent surface. The total length of the small intestines is about 19 m.

The pancreas secretes digestive enzymes, and the liver located in the right hypochondrium produces bile, contributing to a better absorption of nutrients by the body of the pig.

The large intestine and the straight line provide the final absorption of proteins, fats and carbohydrates by the body of the pig, and the total length of the intestines can reach 20 meters or more.

Porcine cardiovascular and respiratory systems

The structure of the heart of a pig is similar to a cow. It is located in the region of junction 7 of the rib with costal cartilage, and has an endocardium, myocardium and pericardium. This is a hollow muscle bag consisting of the atrium and ventricle. Its left side is responsible for pumping the arterial, and the right side is venous blood.

Blood vessels deliver blood from the heart of a piglet or an adult pig to its organs, and it returns back through the veins. When the capillaries touch the cell walls of living tissues, nutrients and oxygen are exchanged.

The cardiovascular system, along with the respiratory system, consisting of the lungs, trachea, larynx and nose with the nasal cavity, is the basis for the full functioning of the body of the pig.

Pigs have sexual reproduction. The males have developed male genital organs, in which spermatozoa develop. The females produce eggs, which during fertilization give rise to a new life. With proper maintenance and feeding, the producer is able to cover tens of thousands of pigs throughout life, and a healthy sow provides two farrowings per year, in each of which it can lead from 12 to 18 piglets.

In the article "Sexual organs and the reproductive system of pigs," read about how the conception and development of piglets occurs in the womb.

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Write in the comments what anomalies in the anatomy of domestic pigs you had to face.




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