Ecological conditions: Hang Pig is also known as Hang Kou Pig or Shang Hang Pig. It is mainly found in the region of the central area Xiushui County, Jiangxi Province. The areas have mild climate and with average temperature ranging from 13.6 to 16.5°c during the year. Rice, maize, wheat and horse-bean are the main crop products here. Farm by-products consisting of rice and potato, maize residue and pollard form the main feedstuff for pigs. In addition, succulent wild growing feedstuffs are in abundance and are also commonly used. The above feedstuffs provide adequate feed sources for the rearing and development of Hang pig. Historically, Xiushui County is a mountainous region lacking communications with outside world and hardly any exotic pig breeds have been introduced here.
The local inhabitants have the custom of slaying big hogs for the New Year to make ham. For this purpose and under such production systems and long cultural practice, Xiushui Pig breed has been developed with the characteristics of: a fatty breed, docile temperament, good taste, good disease resistance and steady heredity. According to classification of Pig Breeds in China, Hang Pig was classified as Central China type (Lai and Huang, 2001; Zhang et al, 1986).
Appearance characteristics: Hang Pig has a medium body and a loose body constitution. Its head is moderate and appears in two forms namely, chimera and doggie. The ears are medium in size and droopy. Moreover, the Hang swine has a slight concave back and loin, big abdomen and wide limbs. The hair is coarse, long and bristle about 7~12cm. They have black back, hindquarters and head while the, abdomen and limbs are white. Some individuals have irregular black and white on the back and waist. Those pigs whose centre of forehead has a little gathered white hair are named small flower face while those with straight white hair are named big flower. On average, Hang sows have 6~7 effective nipples (Zhang et al, 1986).
Production performance: Hang Pig matures early sexually and has high libido. The sow reaches oestrus at 110-118 days of age (Zhang et al, 1986). The Hang gilts can be mated at 7 month age when they weigh about 55kg body, while the boars are mature enough to be used for breeding at the age of 8 months and weighing about 55kg (Zhang et al, 1986). According to the records of Xiushui County Hang Pig breeding farm, the average litter size of Hang Pig sow is 8.34, at first parity with a 50-day litter weight of about 48kg. At the second parity, the litter size of Hang Pig is 8.15 pigs with a 50-day litter weight of about 56kg (Zhang et al, 1986).
In the past, Hang Pigs in the countryside were fed mainly on succulent and low calorie feedstuff, as a result their growth rates were relatively slow. Based on testing data of 12 hogs at 10-16 days, Hang pigs have average daily gain (ADG) of about 300g and dressing percentage of between 68% and 70%. According to testing data of Xiushui County Hang Pig breeding farm, under nutrition level of 8.67MJ/kg DE and 67g/kg CP, the average ADG was 375.4g between 75 and 256 days. Under feed intake level of 13.03MJ/kg DE and 95g/kg CP, the ADG of Hang pigs can reach 477.2g after 167 days of feeding. Currently Hang Pig is usually slaughtered when body weight reaches about 90kg, and attains dressing percentage of 71.7%, lean meat percentage of 34.72% and fat percentage of 50.24%.
Breed utilization: For Crossbreeding: Using middle Yorkshire, SuBai boar mated with Hang sow respectively, the litter size of hybridization offspring at 50 days increased 0.88 and 1.18; the weaned weight improved 60.04% and 38.4%. The ADGs of Yorkshire×Hang and SuBai×Hang of between 451 and 458g have been achieved, and the fattening period shortened to 52-60 days with the carcass weights reaching 90kg. This reflects heterosis percentage of 15.79% and 12.74% for ADG in the two types of crosses, respectively. The heterosis percentage of daily gain/kg is 4.92 and 3.69% respectively.
Evaluation of the genetic diversity: Lin et al (2001) studied the blood protein genetic polymorphism of the Hang breed with eight loci Ab, Pi-I, Pi-II, Po-I, Po-II, Cp, Amy-I and CA by vertical polyacrylamide gel electrophoresis. The results showed that all the markers were polymorphic expect for the locus of Cp, the mean heterozygosity was 0.2478. Clustered with other four studied breeds, the Hang breed was closest to the Dongxiang Spotted breed with an estimated genetic distance value of only 0.0307.
Using a set of 27 microsatellite markers recommended by the Food and Agriculture Organization of the United Nations and International Society of Animal Genetics (FAO-ISGA), Sun et al (2002) studied the genetic variation of Hang breed and found all of them to be polymorphic, with the polymorphic information content of 0.77. Genetic clustering of the breed with other 17 Chinese indigenous pig breeds in their study showed that the Hang breed was genetically very close to the other breeds of the Central China type. Zhang et al. (2003), using the same sets of markers and using Hang breed, recorded an average heterozygosity of all markers of 0.80, with the mean number of the observed and effective alleles of 10.38 and 5.96, respectively. Clustering with other 55 Chinese indigenous pig breeds, the Hang breed clustered with the Tongcheng breed firstly, then with other breeds of the Central China type.
1. Lai Y. B. and F. Y. Huang, Breeds of domestic animal and poultry in Jiangxi Province, 2001, pp77-82.
2. Lin L., Z.G. Wang, B. Liu, Analysis of the genetic structure six Chinese indigenous pig breeds with five serum protein loci, Journal of Huazhong Agricultural University, 2001, Vol. 20(6): 511-515.
3. Sun F., Y. Zhang, Z. Wang, Study on the genetic relationship among 18 Chinese local breeds using microsatellite DNA markers, 7th World Congress on Genetics Applied to Livestock Production, August 19-23, 2002, Montpellier, France.
4. Zhang G .X., Z. G. Wang, F. Z. Sun, Genetic diversity of microsatellite loci fifty-six in Chinese native pig breeds, Acta Genetica Sinica, 2003, 30(3): 225-233.
5. Zhang Z. G., B. T. Li, X. H. Chen, Pig Breeds in China, Shanghai Scientific and Technical Publishers, 1986, pp103-107.