For exploring genetic diversity of Juema pig, researched on the polymorphism of growth hormone gene order of Juema pig, and selected sequences in 14 kinds of pig from GenBank. Full sequence of growth hormone gene of 7 Juema pigs had been cloned successfully for the first time, from which 5 Juema pigs were sequenced respectively, whose polymorphism is intron 1 contains 1 commutation and 1 transversion, intron 2 contains 2 transversions, explain that the difference between Juma pigs may be connected with controlling of intron. The variation of 155 nucleotide all were detected in coding and noncoding region by comparing Juema pig with other 14 breeds, and 119 out of them were in intron regions and 28 out of them were in exon regions, with 104 transversions, 14 commutations, 23 absences, 14 inserts among them. Among substitutive sites of basic group, most was transversion mutations; the comparision between transversion and commutations was 7.43∶1, which exists transversion bias phenomenon. The percentage and divergence number of Juema pig’s growth hormone gene homology analyse showed that homology was nearer by comparing Juema pig with other minitype pig, homology of Juema pig and other large pig was farer. Dendrogram of growth hormone gene sequence in Juema pig etc. of 15 kinds analyse, which indicated Juema pig having far distant genetic relationship with the Vize pig; Juema pig and Rongjiang pig’s genetic relationships were nearest.

In order to formulate scientifically immunization programs to control PRRS basically, the maternal antibodies and immune antibodies of sows, sucking pigs and piglets were detected respectively by ELISA diagnostic kits. Trials have proved that the first immunization of the breeding sows was 15 days before hybridization, and the second immunization of pregnant sows was 2 months before pregnancy, the third immunization of the breeding sows was 15 days before the second hybridization, this production cycle of immunization can control PRRS infection. Because after the parturient sow 1 month immunized PRRS inactivated vaccine, the maternal antibody of piglets decreased gradually and was negative at 60 days, the first immuniza-tion of piglets was approximately 45-day-old, besides. When 40-day-old piglets PRRS were immunized inactivates vaccine, the antibody S/P average of 58-day-old was the highest, and the 160-day-old was negative which could not resist the infection of PRRSV. Injecting the 40-day-old piglets were immunized 2 mL PRRS inactivated vaccine by intramuscular, the second immunization was 70-day-old, then the antibody S/P value was the average maximum at 85-day-old, the 180-day-old finishing pigs was still positive. Therefore, the pigs were safe as the stock exchange, or immunized before hybridization as a back-up sows in breeding. The antibodies of non-immune sows and piglets were negative in control group. The fluctuation law of PRRSV maternal antibodies and immune antibodies by the experiment affords a theoretical basis for the development of immunization programs in the future.