Theses and Dissertations

Issuing Body

Mississippi State University


Rashmir-Raven, Ann M.

Committee Member

Anderson, John D.

Committee Member

Smith, Trent

Committee Member

Linford, Robert L.

Date of Degree


Document Type

Graduate Thesis - Open Access


Veterinary Medical Science

Degree Name

Master of Science (M.S.)


College of Veterinary Medicine


Department of Clinical Sciences


Hyperelastosis Cutis (HC) is an autosomal recessive disorder in Quarter Horses. Homozygous (Hr/Hr) horses are affected with fragile, hyperextensible skin that sloughs and scars easily following minor trauma. Heterozygous (N/Hr) horses appear normal, but carry one copy of the gene. Objectives were to determine inbreeding coefficients of affected (Hr/Hr), carrier (N/Hr), and normal (N/N) Quarter Horses, compared to Thoroughbreds, and evaluate economic effects of HC within the cutting horse industry. Of the top cutting horses from 1985 through 2006, 35 were confirmed carriers by either DNA analysis or production of affected offspring. Although 23% of the earnings from the leading 100 lifetime earning sires ($388 million) were attributed to 12 carrier sires, average offspring earnings of carrier sires were not significantly different from normal sires. The increase in dollars is due to the number of earning offspring produced by carriers, highlighting the need for DNA testing and appropriate breeding selections.