Why are there animals like pigs in the world?

Pig is an omnivorous mammal. Fat body, short limbs, long nose and muzzle, edible meat, leather for tanning, fat body and short limbs, docile nature, strong adaptability, easy to raise, fast reproduction, black, white, red or black and white and other colors . They can be bred 5-12 months after birth, and the gestation period is about 4 months. The average life span is 20 years. It is one of the five animals. Among the twelve zodiac animals, the pig ranks last and is called Hai. There are many allusions and customs about pigs

Pigs are also known as "Yin Zhong", "Tang Ang", "Black Face Lang" and "Hei Ye". In ancient times, it was called pig, also known as pig, pig, and also called rigid hyena. "Chao Ye Qian Zai" said that in the Tang Dynasty, people in Hongzhou became rich by raising pigs and called pigs "Tang Ang". "Yunxian Miscellaneous Notes" of the Tang Dynasty quoted "Old Collection of Taiping": "A black-faced man is called a pig." On the land of China, pigs, dogs and other domestic animals have been raised as early as the period of matrilineal clan communes. The shape of the pottery pig unearthed at the Hemudu Neolithic Cultural Site in Yuyao, Zhejiang is very similar to the shape of the current domestic pig, indicating that the domestication of pigs had already taken shape at that time

The feeding behavior of pigs includes eating and drinking, and Characteristics of various ages. Pigs are born with the genetic characteristic of digging into the soil, and digging into the soil for food is a prominent feature of pigs' feeding behavior. The pig's snout is a highly developed organ, and its sense of smell plays a decisive role when digging through the soil for food. Although pigs are fed a well-balanced diet in modern pig houses, they still exhibit the characteristics of foraging on the ground. When feeding, pigs try to occupy a favorable position in the trough, and sometimes put their two forelimbs on the trough to eat. If the trough is easy to access, some pigs will even get into the trough and stand on the corner of the trough, just like wild boars searching for food. They will move their snout along the trough to stir up the food and scatter it on the ground. Pigs are selective in their food intake and especially like sweets. Studies have found that newborn piglets that are not suckling like sweets. Compared with pellet materials and powdered materials, pigs like to eat pellet materials; compared with dry materials and wet materials, pigs like to eat wet materials and spend less time. Pigs' food intake is competitive. Pigs fed in groups eat more, faster, and gain more weight than pigs fed alone. Pigs eat 6 to 8 times during the day, 1 to 3 times more than at night. Each feeding lasts 10 to 20 minutes, and the feeding time is less than 10 minutes. They eat freely (free feeding). Not only does the feeding time last long, but also It can express the hobbies and personality of each pig. The number of piglets sucking every day and night varies with age, ranging from about 15 to 25 times, accounting for 10% to 20% of the total day and night time. The feed intake and feeding frequency of large pigs increase with the increase in body weight. In most cases, drinking water and eating food are done at the same time. Pigs drink a lot of water. Piglets need to drink water after they are born, mainly from the moisture in breast milk. When piglets eat feed, they drink about twice as much water as dry feed, that is, the ratio of water to feed is 2:1; adult pigs In addition to feed composition, the amount of water consumed depends largely on the ambient temperature. Piglets that eat mixed feed drink 9 to 10 times a day and night, and eat wet feed an average of 2 to 3 times. Pigs that eat dry feed need to drink water immediately after each feed. Pigs that eat ad libitum usually eat and drink alternately. Continue until satisfied, and restrict feeding pigs to drink water only after eating the feed. Piglets before the age of one month can learn to drink from automatic waterers.

2. Excretion Behavior

Pigs do not defecate or urinate in places where they eat and sleep. This is a nature inherited from their ancestors, because wild boars do not defecate or urinate near their nests to avoid being discovered by enemy animals. . Under good management conditions, pigs are the cleanest animals among livestock. Pigs can keep their sleeping dens clean and can defecate and urinate in a fixed place in the pen away from the dens. There is a certain time and area for pigs to defecate and urinate. Generally, they usually choose dark, moist or dirty corners to defecate and urinate after eating, drinking water or when getting up and lying down, and are affected by the influence of neighboring pigs. It has been observed that growing pigs do not defecate during feeding. They start to defecate 1 to 2 times about 5 minutes after they are full. Most of them defecate first and then urinate. They also defecate before feeding, but most of them urinate first. After defecation, pigs mostly urinate and rarely defecate during the interval between two feedings. They usually defecate 2 to 3 times at night, with the largest amount of excretion in the morning. Pigs’ nighttime excretion activity accounts for 1.2 of the total day and night time. %~1.6%.

3. Group behavior

The group behavior of pigs refers to the various interactions that occur between individuals in the pig herd. Pairing is a prominent social activity, with pig groups showing more physical contact and maintaining auditory information transfer. In the absence of a pig house, pigs can live in a fixed place by themselves, showing the habit of settling down and roaming. Pigs are gregarious, but they also have competitive habits, aggressive characteristics such as big bullies, bullies, and bullying. The larger the pig herd, , this phenomenon becomes more obvious. A stable pig herd is formed into a hierarchical community structure based on the principle of dominance sequence. The individuals remain familiar with each other and live in harmony. When the group is regrouped and the stable community structure changes, fierce battles will break out. Until a new community structure is reorganized. The pig herd has an obvious hierarchy, which is formed soon after birth. Within a few hours after the birth of the piglets, fighting behavior will occur in order to compete for the front nipple of the sow. It is often the case that the piglet born first or with a larger weight gets the best nipple. Location. Piglets in the same litter are very gregarious. When they disperse, they are not far from each other. If they are accidentally frightened, they will immediately gather in a group or run away in groups. When the piglets are separated from their sow or littermates, it takes less than a few minutes. , there will be extreme activity, loud screaming, and frequent urination and defecation. Older pigs also behave similarly when separated from their partners.

When pig hierarchies are first formed, aggressive behavior is the most common. The establishment of hierarchies is determined by the breeds that make up the group. The influence of factors such as weight, gender, age and temperament. Generally, pigs with larger weight and stronger temperament have the upper hand, older pigs have the upper hand than younger pigs, male pigs have the upper hand than female pigs, and uncastrated pigs have the upper hand than castrated pigs. Small pigs and pigs newly added to the original group are often ranked second. The determination of the group advantage sequence among piglets in the same litter often depends on the size of the body weight at weaning. When piglets from different litters are fed together, there will begin to be differences. After fierce fighting and lying down in small groups according to different sources, within about 24 to 48 hours, an obvious dominance hierarchy will be formed, usually in a simple linear shape. In older pigs, especially when feeding is restricted, this hierarchical relationship is more obvious. The dominant sequence has both a vertical direction and a parallel and triangular relationship. The winner of the fight is ranked first, and the second is often eaten. Occupy a favorable feeding position or have priority in feeding. In pig herds with similar overall structures, pigs with heavier weights tend to be at the forefront. In groups composed of different breeds, it is not the heavier individuals but the more aggressive breeds or strains that dominate. After the dominance sequence is established, normal life in the peaceful area begins. The intimidation caused by the sharp and loud breathing sounds of the dominant pig and the feint attack with its kiss can replace the biting fight. The inferior pig will retreat immediately and will not A fight breaks out.

4. Fighting Behavior

Fighting behavior includes offensive and defensive activities, avoidance and defensive activities. The fighting behaviors that can be seen in production practice are generally caused by competition for feed and territory. In addition to competing for feed and territory, the mutual confrontation within the newly merged pig herd also has the effect of adjusting the living structure of the pig group. When a strange pig enters a group, the pig will become the target of attacks by the whole group of pigs. The attacks are often severe, with minor injuries to the skin and flesh, and severe ones causing death. If two unfamiliar sexually mature boars are put together, they will fight fiercely. They circle and sniff each other, sometimes lying on the ground with their forelimbs, making a low roar, and suddenly snapping with their mouths. This fight may last for an hour. The surrendered pigs often turn around and howl to escape the scene of the fight. , although a fight between two pigs rarely causes casualties, one or both parties will cause huge losses. In hot summer, a fight between two young boars often results in the death of one or both parties due to extreme heat exhaustion. The fighting behavior of pigs is mostly affected by the breeding density. When the density of the pig group is too high and the space occupied by each pig decreases, the number and intensity of fighting within the group will increase, which will cause the pigs to increase their aggressive behavior when eating. Reduce feed intake and weight gain. One form of this kind of fighting is biting the opponent's head, and the other is tail-biting fighting in a group of pigs raised in a house. The newly gregarious pigs mainly compete for the secondary position in the group, not for feed. Only when the group structure is formed, more fights for food and territory will occur.

5. Sexual behavior

Sexual behavior includes estrus, courtship and mating behaviors. During the estrus period, sows can see specific courtship performances, and both male and sows show some mating behaviors. previous behavior. Sows in estrus mainly show restlessness, appetite fluctuating, making a unique soft and rhythmic humming sound, climbing over other sows, or waiting for other sows to climb over, and urinating frequently, especially when boars are present. Urinating more frequently. In the middle of estrus, during the period of high sexual desire, when the boar approaches, the sow will move her buttocks close to the boar, smell the boar's head, anus and penis foreskin, stay close to the boar, and even climb across the boar. Finally, Stand still. Accept the boar astride. When managers press the sow's back, the freezing reflex immediately appears. This freezing reflex is a key behavior of sows in estrus. Once a boar comes into contact with a sow, he will chase her, sniff her side ribs and vulva, insert his mouth between the sow's legs, and suddenly move the sow's buttocks upwards, foaming at the mouth, and often making continuous noises. A soft and rhythmic guttural hum, some people call this unique sound a "mating song". When the boar is sexually excited, there will also be rhythmic urination. Some sows show obvious mate selection and show a strong dislike for individual boars. Some sows have hyperactive sexual behavior due to endogenous hormone secretion imbalance, or are not in estrus or have insignificant estrus. Due to the relationship between nutrition and exercise, boars often suffer from low sexual desire or masturbation. Raising boars in groups often leads to stable same-sex sexual habits. Boars with low status in the group are often crawled by other boars. Across.

6. Maternal Behavior

Maternal behavior includes a series of behaviors of sows before and after farrowing, such as nesting, suckling and other activities of raising piglets.

Sows

When sows are about to give birth, they usually behave in the form of holding grass and laying down the pig bed. If the pen is on a cement floor without straw, they have to use It is indicated by scratching the ground with its hooves. 24 hours before farrowing, the sow appears restless, urinating frequently, grinding her teeth, wagging her tail, arching the ground, getting up and lying down, and constantly changing her posture. When giving birth, it is common to lie on the side and choose the quietest time to give birth, usually after 4 pm, especially at night. After the first piglet is born, the sow sometimes screams. When the piglet sucks the sow, the sow straightens her limbs and opens her nipples to let the newborn piglets suck. During the entire delivery process, the sow is in a milk-releasing state from beginning to end and keeps humming. The breast milk nipples are full, and even the milk flows out easily for the piglets to suck.

After giving birth, the sow lies down in a position with her breasts fully exposed, forming a heat source to induce the piglets to lie down next to the sow's breasts. When breastfeeding, they often lie down on the left or right. Without turning around during a feeding, both mothers and piglets can Actively eliciting suckling behavior, the sow purrs with a low, rhythmic grunt. When piglets are suckling, sometimes the piglet initiates suckling by calling her and continuously touching the sow's udder. When a sow is suckling, the cry of the sow's piglets often causes other sows in the same house to also suck. The piglet sucking process can be divided into four stages. At the beginning, the piglets gather at the udder, each occupying a certain position, rubbing the udder with their noses, and sucking. The piglets stand backward, their tails are tightly curled, and their forelimbs extend straight forward. At this time, the sow The humming reaches its peak, and finally the milk discharge is completed. The piglet massages the udder again and the suckling stops. Mothers and piglets identify and communicate with each other through smell, hearing and vision. The pig's cry is a kind of communication information. For example, the sounds of nursing sows and piglets can be divided into hmm-hmm sounds (sows made by sows when they are affectionate) and screams (piglets' sounds) according to the part of the sound they make (guttural or nasal sounds) and the difference in sound. There are three types of sounds: panic sounds) and nasopharyngeal sounds (warning sounds and attack sounds of sows protecting their piglets). With these different calls, mothers and piglets convey messages to each other. The sow pays great attention to protecting her piglets. She is very cautious when walking and lying down, and does not step on or crush the piglets. When the sow is lying down, she chooses to lean on the triangle of the pen and continuously use her mouth to expel the piglets slowly and slowly. Lie down against the fence to prevent the piglets from being crushed. Once you encounter a piglet being crushed, as soon as you hear the scream of the piglet, stand up immediately and repeat the anti-pressure action until the piglet is no longer suppressed. When a sow with her piglets is invaded by an outsider, she will first let out an alarm roar. The piglets will flee or lie motionless upon hearing the sound. The sow will open and close her jaws to threaten the aggressor, or even attack. Sows that have just given birth will show strong aggressive behavior even if the breeders try to catch the piglets. These maternal behaviors are particularly evident in local pig breeds. Modern breeding breeds, especially highly selected lean pig breeds, have reduced maternal behavior.

7. Activity and sleep

Pig behavior has an obvious circadian rhythm, and most of its activities occur during the day, in warm seasons and summer. There are also activities and feeding at night. In cold weather, the activity time is shortened. The day and night activities of pigs also vary depending on their age and production characteristics. The average day and night rest time of piglets is 60% to 70%, that of breeding pigs is 70%, that of sows is 80% to 85%, and that of fattening pigs is 70% to 85%. The peak period of rest is in the middle of the night, and the least rest is around 8 o'clock in the morning. The sleeping time of lactating sows gradually decreases as the number of lactation days increases, the number of movements increases from less to more, and the time increases from short to long. This is a unique behavior of lactating sows. There are two types of sleeping positions for lactating sows, one is lying quietly, and the other is sleeping deeply. The resting position of sleeping sows is mostly on the side, and rarely on the stomach. The breathing is light and even. Although the eyes are closed, it is easy to wake up, and the sleeping position of deep sleep is on the side. Lying down, breathing deeply and long, snoring and often trembling fur, difficult to wake up. Within 3 days after birth, piglets sleep almost exclusively except for sucking milk and excreting. As the piglets grow older and improve their physique, their activity level gradually increases and their sleep decreases accordingly. However, by the 40th day of age, after eating a large amount of food and supplements, they will no longer sleep. The sleeping time increases again, and sleep is generally quieter after a full meal. Piglets generally follow the sow in their activities and sleep. Piglets in the same litter begin to move in groups about 10 days after birth, with little individual activity. Sleep rest is mainly characterized by sleeping in groups.

8. Exploration Behavior

Exploration behavior includes exploratory activities and experiential behaviors. Most of the general activities of pigs come from exploratory behavior. Most of them are directed towards objects on the ground. They explore through the senses such as seeing, hearing, smelling, tasting, gnawing, and arching. They show well-developed exploratory physical strength. The exploratory physical strength refers to It is the exploration and investigation of the environment and the empirical interaction with the environment. Pigs have two reactions: curiosity and closeness to many things they are familiar with in recent explorations. Piglets are "curious" about everything in their small environment and show closeness to their littermates. Exploring behavior is obvious in piglets. Piglets can stand up about 2 minutes after birth and begin to search for the sow’s nipples. Digging with their noses is the main method of exploration. Another obvious feature of the piglet's exploratory behavior is that it uses its nose and mouth to bite all new things in the surrounding environment. Using the nasal protrusion to play with objects in the surrounding environment is the main aspect of pig exploratory behavior, and its duration is longer than group play time. When pigs are looking for food, they first perform digging movements. They first use their noses to smell, dig, lick, and gnaw. When the food attractants suit their taste, they open their mouths to eat. This feeding process is also an exploratory behavior. Similarly, the order in which the piglets suck the sow's nipples and the accurate identification of the sow's piglets with each other are also established through smell and taste exploration. Pigs can clearly distinguish different areas for sleeping, eating, and excretion in the pig pen. This is also formed by using the sense of smell of the nose to distinguish different odors.

9. Abnormal behavior

Abnormal behavior refers to behavior beyond the normal range. Vice is abnormal behavior that causes harm to humans and animals or brings economic losses. Its occurrence is mostly related to animals. related to harmful stimuli in the environment. For example, sows that have been confined for a long time will chew the iron teats of automatic waterers persistently and stubbornly. Sows live in monotonous and boring fences or cages, and often gnaw on the railing posts in front of the cage manically.

Generally, as the range of activities becomes more restricted, the frequency and intensity of biting the fence posts will increase, and the aggressive behavior will also increase. Pigs with hyperactive tongues often roll up the tip of their tongues and constantly expand and contract in their mouths, and some will also appear Arching and chewing. Cannibalism is another harmful vice, such as cannibalism in postpartum sows. Abnormal tail biting behavior often occurs in crowded captive conditions, or in nutritionally deficient or boring environments, causing great harm to production.

10. Aftereffect Behaviors

Some pig behaviors are born, such as foraging, sow breastfeeding and sexual behaviors, while others are acquired, such as learning to Behaviors such as identifying certain things and following people's instructions, etc., acquired behaviors are called conditioned reflex behaviors, or aftereffect behaviors. Aftereffect behavior is gradually established after pigs become familiar with new things. Pigs have a strong memory for eating and drinking. It is easiest to establish conditioned reflexes regarding feeding tools, troughs, drinking water troughs and their locations. For example, when piglets are artificially breastfed, they are fed regularly every day. As long as they are fed on time, Give the dog the sound of a flute or a bell or the beating of a feeding utensil. After training for a few times, he can follow the signal command and go to the designated place to eat. This shows that pigs have aftereffect behavior. Through any training, pigs can establish the reaction of aftereffect behavior and obey human instructions to achieve the purpose of improving production efficiency.

Classification of local pig breeds

Classification by geographical area 1. North China types: folk pigs, Huanghuaihai black pigs, Licha black pigs, Bamei pigs, etc.; 2. South China types : Southern Yunnan small-eared pigs, Lantang pigs, Luchuan pigs, etc.; 3. Central China types: Ningxiang pigs, Jinhua pigs, Jianli pigs, large white pigs, etc.; 4. Jianghai types: the famous Taihu pigs (Meishan, Erhuaface, etc.) (collectively); 5. Southwest types: Neijiang pigs, Rongchang pigs, etc.; 6. Plateau types: Tibetan pigs (Aba, Diqing, Hehe Tibetan pigs).

Large White Pig

Large White Pig

Also known as "Big York Pig". Originating in the UK, it is specially called the "British Great White Pig". After being imported into the Soviet Union, after a long period of domestication and cultivation, it became the "Soviet White Pig". The latter's body is stronger and thicker than the former's, and its limbs are strong and powerful, making it suitable for grazing. Bred in England in the 18th century. Yorkshire pig is a famous breed of pig. Originating in Yorkshire, England (Yorkshire, an old county in northeastern England, divided into North Yorkshire, South Yorkshire and West Yorkshire in 1974), it is bred by crossbreeding local pigs with Chinese pigs. The whole body is white, and the ears stand forward. There are three types: large, medium and small, which are called "big white pig", "medium white pig" and "small white pig" respectively. The Large White pig is a cured meat type and is the most widely distributed pig breed in the world. The body grows larger, with adult boars weighing 300 to 500 kilograms and sows weighing 200 to 350 kilograms. It has strong reproductive capacity, giving birth to ten to twelve offspring per litter. Young white pigs mature early and become fat easily, and they are fat type. The size of the medium white pig is between the two, and it is a meat type. China raises more large white pigs.

Landrace pig

is the common name for "Landrace pig" in China. Famous bacon type pig breed. Originally from Denmark. It is bred from a cross between local pigs and Large White pigs. The whole body is white. The body drive is special and streamlined. The head is long and narrow, the ears are large and droop forward, the back and waist are straight, the hindquarters are well developed, the thighs are plump, and the limbs are high. Fast growth and high feed utilization. The skin is thin and the meat is lean. Each litter gives birth to eleven to twelve piglets. Adult boars weigh between 400 and 500 kilograms, and sows weigh about 300 kilograms. Requires better feeding and management conditions. Found in countries all over the world.

Hampshire pig

Hampshire sow

is a famous meat pig breed. In the early 19th century, it was imported from Hampshire, England to the United States, and was bred in Kentucky through cross-breeding. The coat is black, and the shoulder and neck joints and forelimbs are white. The nasal surface is slightly long, straight and erect. The body is long and muscular. Adult boars weigh between 315 and 410 kilograms, and sows weigh between 250 and 340 kilograms. It is precocious and has medium fecundity, with an average of eight litters per litter. Strong maternal instinct. The carcass is of high quality and has a large proportion of lean meat.

Bozhong pig

is a famous breed of pig. Native to the United States. It is a cross between Chinese pigs, Russian pigs, British pigs, etc. Originally a fat type, it has been bred for meat. The whole body is black with six white features. The nose is straight and the ears are semi-drooped. They are large in size, with adult boars weighing 390 to 450 kilograms and sows weighing 300 to 400 kilograms. It matures early and is easy to fatten, and its carcass quality is excellent; but its reproductive capacity is weak, with about eight offspring per litter.

Horse pig

Horse pig

Horse pig is native to Shanxi, China. It is larger in size, with large ears that droop beyond the end of the nose. The barrel length is straight, the back and waist are straight and narrow, the buttocks are sloping, the limbs are strong and strong, the skin and fur are black, thick, thick and dense, with dense brown-red hair in winter, and 7 to 10 pairs of nipples. It can be divided into three types: "big horse-bodied pig" (large), "two-horse-bodied pig" (medium) and "bowen pig" (small). Although the growth rate is slow, the carcass lean meat rate is high.

Domestic pig breeds

Domestic pigs

Beltsville No. 1 pig and Beltsville No. 2 pig (for meat) were both bred in the United States by Beltsville pigs. Weir pigs No. 1 are black and No. 2 pigs are red. Berkshire pigs are used for meat (for meat). The UK, Japan, Australia, New Zealand, and South America are medium-sized and mostly black. They are bred in various places for fresh or cured meat. Used Chester White pigs (for fat) bred in Chester County, Pennsylvania. They are large, white, light pink in color, mild in nature, fertile sows. Duroc pigs or Duroc Jersey pigs (for fat) are North and South American in length. Medium, long, black, 1/2 Jersey pig, 1/2 Durock, Hampshire pig (for meat) American breed, medium weight, long, black, lively, smart, suitable for grazing and raising Hereford pigs (for fat) ) Medium-sized, light red to dark red fat Nordic pigs (for meat) bred in the United States around 1900. Northern Europe, Central Europe and the United States have many medium-sized, white breeds of Maryland No. 1 pigs (for meat). 1. Breed in the United States in 1941. Medium-sized, black with white spots. About 60% Nordic pigs and 40% Berkshire pigs. Minnesota No. 1, 2 and 3 pigs (for meat). Breed in the United States with various body colors, all of which are Montana pigs for meat. Take the No. 1 pig (for meat). Palouse pig (for meat), a cross between Nordic pig and Hampshire pig, was bred in the United States in the 1930s with a slightly arched back and flat cheeks. It was bred in the United States in 1941. It is white and has a medium weight of 2/3. Nordic pig, 1/3 Chester white pig, Polish pig (for meat) bred in the United States to be black, but the legs, nose and tail are white, bred from Russian pigs, Byfield pigs and Chinese pigs, Polish pig (for meat) Breed in the United States, it is white but has black legs. It is also called spotted pig, Tamworth pig (for meat). The United States, the United Kingdom, New Zealand, Australia, and Canada are large in size and have different body colors. They are used for cross-breeding to make cured meat. Pigs (for meat)

Edit this section on pig raising methods

1. Implement protective feeding. In summer and autumn, gourds, melons, melons, sunflowers and other plants are planted outside the pig house to provide shade and cool down. In winter, plastic greenhouse feeding technology is promoted, and deworming and immunization are carried out regularly. 2. Promote high-density pig farming. One fattening pig is raised in a 0.8 square meter pig house in winter, and one fattening pig is raised in a 1 square meter pig house in summer. Raising pigs at high density not only requires fewer pens and is less expensive, but also allows fattening pigs to compete for food. If there is no activity space, they will sleep after eating. They like to grow meat, gain weight quickly, and reduce feeding costs. 3. After fattening pigs exceed 90 kilograms, their daily weight gain slows down significantly, and fat deposition is the main factor. Therefore, the more they are fed, the less economical they are, and the fat meat increases, making it difficult to sell. If they are slaughtered under 90 kilograms, although the feed utilization rate is high, However, due to their small weight and low meat yield, it is not economically feasible. Generally, fattening pigs weighing 90 to 120 kilograms are most suitable for slaughtering. 4. The variety should be excellent. First, choose the variety according to market demand. At present, to promote multiple crosses, at least three yuan, preferably five yuan, such as the British PIC pig, five lines are matched, the growth rate is fast, it can reach 110 kilograms in 158 days, the lean rate is 66%, and the feed-to-meat ratio is 2.8 :1. 5. The column house should be simple. The pig house should not be built too luxuriously, as long as it is cold-proof, warm and ventilated. 6 Feed should be cheap. Feed accounts for 70-75% of the cost of raising pigs. The feed formula should change with market prices and seasonal changes, and should not be static. If pigs eat less in hot weather in summer, the feed should be more nutritious. Feed nutrition should be balanced to meet growth needs. 7. Epidemic prevention must be strict. Pay attention to disinfection, not only to prevent external diseases, but also to prevent fecal contamination and the spread of diseases, and to inject vaccines according to the immunization program. 8 The market should be put out at the right time. For example, when the weight of binary pigs reaches 70 kilograms, inner three yuan 80-85 kilograms, outer three yuan 95 kilograms, and British PIC pigs 105 kilograms, it is the timely weight for slaughter. In addition, when the market price of live pigs is high, the heavier the weight, the better; when the price is low, it is better to have a lighter weight to reduce feed consumption and cost. 9 The "back-feeding method" of pig raising is a new pig raising method determined in response to the above shortcomings and combined with the birth patterns and characteristics of pigs. This method is used in the stage of piglets to middle pigs. That is, before 50-60 kg, high-energy and high-protein concentrates are mainly used, with necessary feed additives and a small amount of green and green feed. From the middle pig to the slaughter period, appropriately reduce the amount of concentrated feed and increase green and roughage. The proportion is: 60% of concentrated feed, 25% of green feed, and 15% of roughage. This method not only shortens the pig feeding cycle, but also makes full use of a large amount of green and roughage resources, thus saving the amount of concentrated feed and greatly improving economic benefits. 10 Feeding and management: Scientific feeding, reasonable matching of feed according to the different uses, ages and growth needs of pigs, strengthening management, improving hygiene, and preventing diseases.

In fact, it evolved from primitive cells and was born like all animals in the world.