A single nucleotide polymorphism in the dopamine receptor D2 gene may be informative for resistance to fescue toxicosis in angus-based cattle

Anim Biotechnol. 2014;25(1):1-12. doi: 10.1080/10495398.2013.796960.


Fescue toxicosis (FT) reduces beef animal growth and fertility. Animals afflicted with FT typically have decreased circulating prolactin concentrations and thicker summer hair coats. Preliminary experiments examined the informativeness of a novel Dopamine Receptor 2 (DRD2) G/A SNP for resistance to FT. Steers grazed tall fescue containing a toxic (E+) or non-toxic (NTE) strain of endophyte. Decreased serum prolactin concentrations were observed in GG steers in May compared to AA steers when grazing E+ pastures (P < 0.02). In a second study, GG steers had decreased prolactin concentrations (P = 0.004) and increased hair coat scores (P = 0.01) relative to AA steers when grazing E+ pastures. Allele and genotypic frequencies were different (P = 0.016 and 0.026, respectively) between spring-calving and fall-calving herds grazing E+ pastures, such that the A allele and the AA genotype were more prevalent in spring-calving herds, suggesting active selection for the A allele. Regardless of calving season, AA heifers tended toward fewer days to first calf (733.6 ± 4.4 d) than did GG heifers (756.6 ± 9.2 days; P = 0.055). These results suggest that the DRD2 SNP may have use in selecting animals resistant to FT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • Cattle Diseases / genetics*
  • Female
  • Genotype
  • Lolium
  • Male
  • Molecular Sequence Data
  • Mycotoxicosis / genetics*
  • Phenotype
  • Polymorphism, Single Nucleotide / genetics*
  • Prolactin / blood
  • Receptors, Dopamine D2 / genetics*


  • Receptors, Dopamine D2
  • Prolactin