Submitted to: Meat Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2002
Publication Date: 3/1/2003
Citation: BURKE, J.M., APPLE, J.K., ROBERTS, W.J., BOGER, C.B., KEGLEY, E.B. 2003. EFFECT OF BREED-TYPE ON PERFORMANCE AND CARCASS TRAITS OF INTENSIVELY MANAGED HAIR SHEEP. Meat Science. 63:309-315. Interpretive Summary: Growth and carcass traits of Dorper-sired, St. Croix-sired and Katahdin lambs, hair breeds of sheep, were examined. Lambs were managed intensively from weaning (60 days of age) until harvest (180 days of age). Results indicate that improvements in live animal performance, carcass muscularity, and quality can be achieved by using Dorper sires on purebred and crossbred St. Croix dams. This information is important to producers and extension agents with an interest in hair sheep. Management strategies for Dorper-sired lambs can include an intensive system with a productive outcome.
Technical Abstract: Live animal performance and carcass characteristics were compared between intensively managed Katahdin (KA), St. Croix (SC), St. Croix-¬ Romanov (SX), Dorper St. Croix (DS), and Dorper Romanov St. Croix (DX) wether lambs. From birth to weaning, KA and DS lambs had higher daily gains (ADG) than SC and SX lambs; conversely, from weaning to harvest, DS had the highest ADG, followed by DX, SC, SX, and KA. Carcasses from DS- lambs were heavier than all other breed types; whereas, carcasses from KA, SX, DS, and DX had greater fat thickness measurements. Although fatter, carcasses of DX and DS lambs had the largest, and SC and SX lambs the smallest longissimus thoracic (LT) areas. Skeletal, lean, and overall maturities were similar among the breed types; however, carcasses from SC lambs received lower flank streaking scores than SX, DS, and KA. Conformation scores for DX and DS carcasses were greater, resulting in higher quality grades, than SC or SX carcasses. Although L* values of the LT were similar, the LM from DX lambs was redder and more yellow than SC and DS. Finally, LT chops from KA lambs had higher shear force values than all other breed types. Results indicate that improvements in live animal performance, carcass muscularity, and quality can be achieved by using Dorper sires on purebred and crossbred St. Croix dams.