Polymorphism within TATA-box of bovine lactoferrin gene and its association with performance traits in Holstein cattle

Bovine lactoferrin (LTF) is a well known glycoprotein present in mammalian milk. LTF has many biological functions, such as: non-specific immune defense against pathogens, immunomodulatory activity, iron homeostasis, antioxidant properties and the regulation of cell growth. Many polymorphisms have been found in the bovine LTF gene. The aim of this study is to find out whether a single SNP (A/C) located at position −28 (within the TATA box) influences the transcription complex in mammary epithelial cells and performance traits in dairy cattle. Four hundred fifty nine Polish Holstein-Friesian bulls and 274 cows—the daughters of 6 bulls were screened by PCR-SSCP method. Cows were selected into two groups showing low (less than 105/ml) and a high (more than 106/ml) somatic cell count measured 10 times during the first lactation. Electrophoretic mobility shift assay (EMSA) showed that the LTF gene was expressed during lactation and that the A allele was bound by the nuclear proteins more efficiently. The C allele was significantly more frequent in cows with low number of SCC (P<0.0001). The effects of LTF genotype on the breeding value of bulls were estimated for 29 traits routinely evaluated in the national database. Significant negative effects of the AA genotype were found for 6 conformation traits and 3 fertility traits. The lack of an antagonistic correlation between allele C of LTF and milk performance traits highlights its benefit for breeding programs.