The main pig breeds introduced from abroad in China are the long white pig, Yorkshire, Duroc, Hampshire pig, and a small number of imported Sigg, French great white pig, Pitland, Belgian long white and Deca "miscellaneous pigs". It can be said that the world's famous excellent lean breed of pigs, Almost all of which are now available in China, have been crossed with local breeds to form more than 300 improved varieties that adapt to the feeding conditions of various places.
First, the long white pig
(1) Originated in Denmark. The head is small, the face is straight, the ears are large and forward-extended, the body is long, the posterior body is developed, and the whole body is narrow and wide in the shape of a wedge, and the whole body is covered with white hair.
(2) Boars are sexually mature at 6 months of age and begin to breed at 8 months of age. Adult boars weigh 400 to 500 kg.
(3) The average weight of sows is 300 kg, the nipples of sows are 7 to 8 pairs, the estrus cycle is 21 to 23 days, the number of litters of primary sows is 8 to 10, and the number of litters produced by sows is 9 to 13.
(4) Piglets weigh more than 1.30 kg at birth, weigh more than 90 kg at 6 months old, gain an average daily weight of 800 g, feed-meat ratio is 2.6:1, slaughter rate is 72%, lean meat rate is 62%.
(5) The long white pig has high production performance, stable genetic performance, remarkable hybridization effect and good coordination.
(6) The disadvantage is that it is not cold resistant, less adaptable, and aggressive.
(7) China introduced the long white pig in 1964, commonly known as the old third series, also known as the British-Swiss series, but due to the neglect of breeding work, the production performance declined. In recent years, the long white pig introduced from Denmark, Belgium and Canada, also known as the new trilogy, but relatively speaking, the limbs and hooves are relatively poor, the growth rate and reproductive performance are not as good as the old long white, but the lean meat rate can reach 63% to 65%. It is widely used as a hybrid paternal in various parts of the country, and its hybridization performance is fast growth, provincial feed, and carcass lean meat rate is high.
Second, the great white pig
(1) Originated in the United Kingdom. The head and neck are long, the face is slightly concave, the ears are medium in size, slightly forward-leaning, the body is long, the back is slightly arched, the muscles are developed, and the whole body is covered with white hairs.
(2) Adult boars weigh 300~500 kg.
(3) Sows 200 ~ 350 kg, the number of litters in the first sow nest is about 11, and the number of litters in the sow nest is about 13.
(4) 60-day-old weaning to breed 9 to 10 heads, fove weight 150 to 180 kg, weight 15 to 19 kg. The average daily weight gain is 800 grams, and the ratio of feed to meat is 2.8:1.
(5) The physique and adaptability of the great white pig are better than those of the long white pig, and in the ternary hybrid system, it is generally used as the first mother. It was introduced in China in 1957 and has been widely promoted in central, eastern and southern China. The danish large white pig has the best performance, with an average daily weight gain of 900 grams and a lean meat rate of 63% to 66%.
3. Duroc Pigs
(1) Originated in the United States. Red hairs throughout the body are prominent features.
(2) Sows are generally sexually mature at 6 to 7 months old, with a period of 207 days and a weight of about 120 kg, a 1-year-old sow weighs about 175 kg, and an adult sow weighs 230 to 390 kg.
(3) Boars are about 205 kg, and adult breeding boars weigh 350 to 450 kg.
(4) The newborn sow nest produces about 9 litters, the number of litters produced by sows is about 10, the newborn weight is about 1.5 kg, the weight of the 150-day-old can reach 90 kg, the average daily weight gain is 800 grams, the ratio of feed to meat is 2.9:1, the slaughter rate is 75%, and the lean meat rate is 62%.
(5) Duroc pigs have thick limbs, gentle temperament, cold resistance, strong adaptability, fast growth, high feed utilization rate, and high lean meat rate. At present, it is mostly used as the terminal parent of ternary hybridization in China.
(6) China introduced this variety for the first time from the United States in 1972.
4. Hampshire Pigs
(1) Originated in the United States. The shoulders and forelimbs are surrounded by a white band, and the rest are highlighted by the hairs that are completely black.
(2) Adult breeding boars weigh 315~410 kg.
(3) Sows 250 ~340 kg; sow estrus cycle of 19 to 22 days, the number of litters in the first sow nest is 7 to 8, and the number of litters in the sow dens is 8 to 9.
(4) Piglets to the breeding stage (before the weight of 35 kg) slow weight gain, 160 days old weight up to 90 kg, the average daily weight gain of 700 grams, slaughter rate of 71% to 75%, lean meat rate of more than 64%.
(5) The advantages are thin fat, thin skin, large eye muscle area, and good meat quality.
(6) The disadvantages are late sexual maturity, less littering, poor lactation, and poor litter protection. Boars have a high libido but are selective and are generally used as terminal parents in hybridization.
5. Pitland Pig
(1) Native to Belgium, it is covered with grayish-white hairs mixed with black spots, occasionally has a small amount of brown hair, the ears are medium large and leaning forward, the body width is short, the legs are short, and the hind body is large.
(2) Boars have a strong sexual desire after sexual maturity.
(3) The sow's initial love period is 190 days, the estrus cycle is 18 to 21 days, and each litter gives birth to about 9 litters.
(4) Slow growth, basically stop growing after 90 kg of body weight, 90 kg slaughter rate of 76%, lean meat rate of 70%.
(5) Its advantages are high lean meat rate, basically fat-free, but stress sensitive, slow growth, poor meat quality, difficult to raise on a large scale.
(6) However, the second-generation boar after hybridization with Duroc pig has a better effect.
(7) In quaternary hybridization, Pidu (male) × large white (female) are generally used.
Six, The Deca Pig
(1) The Deca pig is a four-series "Hybrid pig" launched by the American Deca Company:
(2) Its advantages are fast growth, high feed utilization rate and good meat quality.
(3) However, Deca pigs have poor adaptability and low disease resistance. At the same time, due to the conditions and scale of the pig farm, the four lines are difficult to maintain, and they need to be introduced frequently, which is not necessarily economically cost-effective.
(4) And how much superiority this four-line "hybrid pig" has over conventional breeds of ternary hybrid pigs is still worth studying.
(5) In recent years, Deca pigs have been introduced in Beijing, Guangdong, Hubei and other places.