title: A single nucleotide polymorphism in the dopamine receptor D2 gene may be informative for resistance to fescue toxicosis in angus-based cattle.
abstract: 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.
authors.affiliation: a Department of Animal Science , University of Tennessee , Knoxville , Tennessee , USA.
authors.forename: B T
authors.initials: BT
authors.lastname: Campbell
authors.forename: C J
authors.initials: CJ
authors.lastname: Kojima
authors.forename: T A
authors.initials: TA
authors.lastname: Cooper
authors.forename: B C
authors.initials: BC
authors.lastname: Bastin
authors.forename: L
authors.initials: L
authors.lastname: Wojakiewicz
authors.forename: R L
authors.initials: RL
authors.lastname: Kallenbach
authors.forename: F N
authors.initials: FN
authors.lastname: Schrick
authors.forename: J C
authors.initials: JC
authors.lastname: Waller
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002418:Cattle Diseases / Q000235:genetics*; D005260:Female; D005838:Genotype; D008129:Lolium; D008297:Male; D008969:Molecular Sequence Data; D015651:Mycotoxicosis / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011388:Prolactin / Q000097:blood; D017448:Receptors, Dopamine D2 / Q000235:genetics*
chemical_list: D017448:Receptors, Dopamine D2; D011388:Prolactin