Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2001
Publication Date: 7/1/2001
Citation: APPLE, J.K., BURKE, J.M., ROBERTS, W.J., STEPHENSON, J.S., RAKES, L.K. 2001. EFFECT OF BREED TYPE ON THE PERFORMANCE AND CARCASS TRAITS OF HAIR SHEEP. JOINT ABSTRACTS OF THE AMERICAN DAIRY SCIENCE AND SOCIETY OF ANIMAL SCIENCE. 79(Suppl. 1):442. Interpretive Summary:
Technical Abstract: Live animal performance and carcass characteristics were measured for purebred Katahdin (K: n=15) and St. Croix (SC; n=8) lambs, as well as 3/4 St. Croix (SCX; n=8), Dorper x Romanov x St. Croix (DX; n=9), and Dorper x St. Croix (DXSC; n=7) lambs. After weaning, lambs were allowed 4 weeks to acclimate to a high concentrate finishing diet, which was fed for 120 to 127 d. At harvest, K, SC, SCX, DX and DXSC weighed 44.8, 43.7, 42.8, 49.6 and 56.4 kg, respectively. DXSC had the highest (P<0.01) ADG, followed by DX, SC, SCX and K (253.7, 226.1, 204.9, 193.1 and 181.1 g/d, respectively). Carcasses from DXSC lambs were heavier (P<0.01) than all other breed types; whereas, carcasses of K, SCX, DXSC and DX had greater (P<0.01) actual and adjusted fat thickness measurements, and resulting yield grades, than SC. Although fatter, carcasses of DXSC lambs had the largest (P<0.01), and SC and SCX lambs the smallest (P<0.01) longissimus muscle (LM) areas. Although kidney fat weights were similar, carcasses from SCX lambs tended (P<0.08) to have a higher percentage of internal fat than DX, DXSC and K lambs. Skeletal, lean, and overall maturities were not different among the breed types; conversely, carcasses from SC lambs had lower (P<0.05) flank streaking scores than SCX, DXSC, and K, with DX carcasses receiving intermediate scores. Conformation scores for DX and DXSC carcasses were substantially higher (P<0.01), resulting in higher (P<0.01) quality grades, than SC and SCX carcasses. Although L* values of the LM were similar, the LM from DX lambs was redder (P<0.01) and more yellow (P<0.01) than SC and DXSC. Results from this study indicate that improvements in ADG and carcass muscularity and quality can be achieved by using Dorper sires on purebred and crossbred St. Croix dams.