Preliminary Evidence for Association of Prolactin and Prolactin Receptor Genes with Milk Production Traits in Chinese Holsteins

Abstract

Hu, X., Lü, A., Chen, H., Gao, X., Xu, H., Zhang, C., Fang, X. and Lei, C. 2009. Preliminary evidence for association of prolactin and prolactin receptor genes with milk production traits in Chinese Holsteins. J. Appl. Anim. Res., 36: 213–217.

Genetic polymorphisms of prolactin (PRL) and prolactin receptor (PRLR) genes in Chinese Holstein cattle were detected by PCR-SSCP methods. Polymorphisms were observed in both genes and direct sequencing confirmed the A>G mutation at position 8398 in exon 4 of PRL gene and the A>C mutation at position 7866 in intron 9 of PRLR gene. The frequencies of allele A/B and C/D were 0.894/0.106 and 0.781/0.219 for PRL and PRLR genes, respectively. Chinese Holstein cows with genotype BB were observed to be higher milk yielders than genotypes AA and AB (P<0.05). It is concluded that the polymorphism in the PRL gene may be a genetic marker in breeding for milk yields in Holsteins, but further validation is required.

Keywords:

• Cattle
• milk yield
• prolactin gene
• prolactin receptor gene
• polymorphism