The PCR genotyping for a point mutation of ryanodine receptor gene (RYR1) causing porcine stress syndrome (PSS) was able to identify three genotypes. To estimate the PSS gene frequency of three common commercial purebreds: Landrace (L), Duroc (D) and Yorkshire (Y) in Taiwan, boars and sows from one private farm and National Swine Nucleus Herd, North Division (NSNHN) were typed by PSS genotyping. PSS genotyping was also applied to 2,560 male piglets from the Central Boar Test Station (CBTS) from July 1994 to Feb. 1997. Gene frequencies in three purebreds were L: 8.1% (total 1,348 pigs), D: 21.8% (total 1,443 pigs), and Y: 4.0% (total 787 pigs), significantly different in Chi-square test (P < 0.01). Gene frequencies in Landrace, Duroc, and Yorkshire from the private farm were L: 9.4%, D: 21.8%, and Y: 5.2%; from NSNHN were L: 3.4%, D: 6.0%, and Y: 0.5%; and from CBTS were L: 8.5%, D: 24.0%, and Y: 4.3%. Average gene frequencies of 7 purebred herds in CBTS were different (from 8.2% to 44.1 %), and at a significant level by Chi-square test (P < 0.01). Average gene frequencies of 7 purebred herds have dropped from 1994 to 1997 but not at a significantly different level (P > 0.05). 24 Native Small-Ear pigs from Pig Research Institute Taiwan were PSS gene-free by PCR genotyping.
The PCR genotyping for a point mutation of ryanodine receptor gene (RYR1) causing porcine stress syndrome (PSS) was able to identify three genotypes. To estimate the PSS gene frequency of three common commercial purebreds: Landrace (L), Duroc (D) and Yorkshire (Y) in Taiwan, boars and sows from one private farm and National Swine Nucleus Herd, North Division (NSNHN) were typed by PSS genotyping. PSS genotyping was also applied to 2,560 male piglets from the Central Boar Test Station (CBTS) from July 1994 to Feb. 1997. Gene frequencies in three purebreds were L: 8.1% (total 1,348 pigs), D: 21.8% (total 1,443 pigs), and Y: 4.0% (total 787 pigs), significantly different in Chi-square test (P < 0.01). Gene frequencies in Landrace, Duroc, and Yorkshire from the private farm were L: 9.4%, D: 21.8%, and Y: 5.2%; from NSNHN were L: 3.4%, D: 6.0%, and Y: 0.5%; and from CBTS were L: 8.5%, D: 24.0%, and Y: 4.3%. Average gene frequencies of 7 purebred herds in CBTS were different (from 8.2% to 44.1 %), and at a significant level by Chi-square test (P < 0.01). Average gene frequencies of 7 purebred herds have dropped from 1994 to 1997 but not at a significantly different level (P > 0.05). 24 Native Small-Ear pigs from Pig Research Institute Taiwan were PSS gene-free by PCR genotyping.