Biological detection of heterozygosity for double muscling in cattle. II. Thyroid hormone concentrations.
Serum levels of triiodothyronine and thyroxine were measured by radioimmunoassay to determine whether differences exist between double-muscled (DM) homozygous, DM heterozygous and non-DM cattle of beef and dairy origins. No differences in triiodothyronine concentrations were found between heterozygous and non-DM beef animals, but thyroxine concentrations in non-DM dairy cattle were significantly different from those in non-DM beef. Unexpectedly, hormone concentrations in DM homozygotes were lower than those in other genotypes.
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000235:genetics*; D006580:Genetic Carrier Screening; D006984:Hypertrophy; D009135:Muscular Diseases / Q000097:blood / Q000473:pathology / Q000662:veterinary*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D014284:Triiodothyronine; D013974:Thyroxine