The Relationship Between BLF Gene Polymorphism And Mastitis Of Dairy Cows

PCR-SSCP was applied to analyze the association of polymorphisms of lactoferrin gene, totally 133 Chinese Holstein were used as research populations. And the association between genetic marker and the mastitis was analyzed using the general linear model (GLM). After carry out sequence analyzing on these several polymorphic site by the sequencing technique, results were as follows:1. Four polymorphic sites were detected, they were BLF-5'region, BLF-intron 8, BLF-intron 10 and BLF-intron 14. The BLF-5'region locus,BLF-intron 8 locus may possibly have some associativity with mastitis. But the BLF-intron 10 and BLF-intron 14 locus have not. And there were no polymorphism in detected extron site.2. Three genetype were found after PCR-SSCP analyzing in BLF-5'site, and their were genetype AA, genetype BB and genetype AB. Indicated as the sequencing consequence that there was a C to T divert at -149 location, a G to A transitions at -135 location and a T deletion at -130 location in genetype BB that compared with genetype AA. These several mutational site were all located in upstream control element (UCE) region. Theχ2 test of BLF-5'region site was 7.9942(P<0.01), and this explained that the polymorphism locus did not fit Hardy-Weinberg equilibrium. Using the SPSS(V12.0)software in calculating the SCSLAW and its standard error in different genetype, the result manifest that the maximum of SCSLAW was BLF-5'genetype AA and the minimum was BLF-5'genetype BB in sample colonia and they had a very significant deviation(P<0.01). In the meanwhile, the highest genetype distribution rate in BLF-5'gene locus was genetype AA either in infected cow or in healthy cow. Indicated that Blf 5'-BB may had some relevant to the resistance of mastitis and Blf 5'-AA may had relevant to the susceptibility of mastitis.3. Gained six genetype after PCR-SSCP analyzing in the amplificate production of BLF-intron 8, and their were genetype AA, BB, CC, AB, BC and AC. Indicated as the sequencing consequence that there was a G-A transition at 842bp, a insertion of A at 843bp, a T-C transition at 914bp and a G-A transitions both at 926bp and 928bp in genetype BB in comparing with genetype AA. And there was a insertion of G at 913bp, a T-C transitions at 914bp and a G-A transitions both at 926bp and 928bp in genetype CC in comparing with genetype AA. Theχ2 test of BLF-intron 8 locus was 13.9307(P<0.01), and this explained that the polymorphism locus did not fit Hardy-Weinberg equilibrium. Using the SPSS(V12.0)software in calculating the SCSLAW and its standard error in different genetype, and detected that there was a significant deviation at the eighth intron gene locus of BLF. The maximum of SCSLAW was BLF-intron 8 genetype AC and the minimum was BLF-intron 8 genetype BC in sample colonia. Except the genetype BB and genetype CC, the least square mean of other genetype were all had significant deviation(P<0.05). The distribution of each genetype on BLF -intron 8 locus in healthy cow and infected cow were that the least distribution in infected cow was genetype BB and genetype BC and the most was genetype AC. These indicated that BLF-intron 8AA, BLF-intron 8AB and BLF-intron 8BC may had some relevant to the resistance of mastitis and BLF-intron 8AC may had relevant to the susceptibility of mastitis.4. Lactation and aetas are two main factors that affect mastitis. It is very obviously that with the increasing of age the morbility of mastitis is also ascensused. Season is a secondary affecting factor of mastitis. In damp and wetting days, dairy cow have more chance suffering mastitis. Lactation month also affect the development of mastitis. Generally speaking, the morbility of mastitis is ascensusing with the progressively increasing of lactation month and the addition of lactation, although the SCS which reflect the incidence of mastitis may fluctuated in different lactation month.