Association of polymorphism in DGAT1and IGF-I with productive and reproductive performance in Holstein cows

The aim of genomic research in dairy cattle is to identify genes which affect the economic traits of importance in animal breeding. The aim of this study was to investigate the polymorphism in the exon 8 of the bovine diacylglycerol acyltransferase 1 (DGAT1) and exon 4 of the bovine insulin-like growth factor-1 (IGF-I) genes and their association with productive and reproductive traits in Holstein cows.
Blood samples from 133 Holstein cows were collected and genomic DNA was extracted using the Sinaclon DNA extraction kit. A fragment of 411 base-pair of exon 8 of DGAT1 gene and a fragment of 312 base-pair of the exon 4 of IGF-I gene were amplified using the polymerase chain reaction (PCR) method. The genes were amplified with specific primers using PCR. The PCR products of DGAT1 and IGF-I were digested by CfrI and MboI restriction enzyme, respectively and their digestion products were electrophoresed on 2.5% agarose gel. Continuous and categorical data were analyzed by the SAS software, using the Proc MIXED and Proc GENMOD, respectively.
There was a significant association between CfrI polymorphism in DGAT1 with milk production and twinning rate. However, there was no association between MboI polymorphism with either productive or reproductive traits.
Although, this study showed an assosiation between polymorphism in DGAT1 gene with milk yield and twinning rate, more research is needed before a firm conclusion can be made.