The identification of quantitative trait loci (QTL) and the subsequent characterization of quantitative trait genes (QTG) have been the objective of several studies in dairy cattle usually using cosmopolitan and widely spread breeds. The effects of these QTG have been only in few cases investigated in local breeds. Reggiana is a local dairy cattle breed that account less than 2000 cows reared in the North of Italy, mainly in the province of Reggio Emilia. Its milk is used for the the production of mono breed Parmigiano Reggiano cheese that is sold at a higher price than undifferentiated cheese. In this study, we analysed 24 candidate gene markers that other studies in other breeds have shown to be associated with milk production and composition traits. A total of 128 Reggiana sires (born from 1984 to 2001) were genotyped. Estimated breeding values were provided by the National Association of Reggiana Breeders (ANABORARE) for the following production traits: milk yield, protein yield and percentage, fat yield and percentage and cheese production index. The effects of the 23 markers on the 6 traits were estimated with a model that accounted for the year of birth and weighted for the reliability level. Two association study methods were used: i) GLM of the software package SAS, without including any pedigree information; ii) ASREML, including pedigree information, and including in the model the random animal effect. Significant associations (P<0.001) were obtained between the DGAT1 p.K232A mutation and fat yield, protein percentage and cheese production index and between a GH1 polymorphism and fat percentage and protein percentage. These results will be useful to evaluate marker assisted selection strategies in Reggiana cattle as genomic selection programmes seem not reliable in numerically small breeds.
Association between twenty four candidate gene markers and milk production and composition traits in Reggiana dairy cattle
FONTANESI, LUCA;SCOTTI, EMILIO;SAMORE', ANTONIA BIANCA;BAGNATO, ALESSANDRO;RUSSO, VINCENZO
2013
Abstract
The identification of quantitative trait loci (QTL) and the subsequent characterization of quantitative trait genes (QTG) have been the objective of several studies in dairy cattle usually using cosmopolitan and widely spread breeds. The effects of these QTG have been only in few cases investigated in local breeds. Reggiana is a local dairy cattle breed that account less than 2000 cows reared in the North of Italy, mainly in the province of Reggio Emilia. Its milk is used for the the production of mono breed Parmigiano Reggiano cheese that is sold at a higher price than undifferentiated cheese. In this study, we analysed 24 candidate gene markers that other studies in other breeds have shown to be associated with milk production and composition traits. A total of 128 Reggiana sires (born from 1984 to 2001) were genotyped. Estimated breeding values were provided by the National Association of Reggiana Breeders (ANABORARE) for the following production traits: milk yield, protein yield and percentage, fat yield and percentage and cheese production index. The effects of the 23 markers on the 6 traits were estimated with a model that accounted for the year of birth and weighted for the reliability level. Two association study methods were used: i) GLM of the software package SAS, without including any pedigree information; ii) ASREML, including pedigree information, and including in the model the random animal effect. Significant associations (P<0.001) were obtained between the DGAT1 p.K232A mutation and fat yield, protein percentage and cheese production index and between a GH1 polymorphism and fat percentage and protein percentage. These results will be useful to evaluate marker assisted selection strategies in Reggiana cattle as genomic selection programmes seem not reliable in numerically small breeds.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
