Submitted to: Small Ruminant Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/26/2005
Publication Date: 12/29/2005
Citation: Burke, J.M., Apple, J.K. 2005. Growth performance and carcass traits of forage-fed hair sheep wethers. Small Ruminant Research. 67:264-270. Interpretive Summary: Hair breeds of sheep are relatively new to the American sheep industry and therefore defined management practices for optimal production are lacking. The objective was to compare growth and carcass traits of hair breeds and Suffolk lambs managed extensively from weaning (60 days of age) until harvest (205 days of age). Results indicate that meat from hair breeds tended to be more tender, and many growth and carcass traits were similar between Dorper and Suffolk lambs. This information is important to a growing number of producers raising hair sheep and extension agents with an interest in hair sheep.
Technical Abstract: The objective was to compare live animal performance and carcass characteristics of 3/4 or 7/8 Dorper (DO; n = 30), purebred Katahdin (KA; n = 20) and St. Croix (SC; n = 17) lambs born in February (FEB; n = 38) and October (OCT; n = 39) 2001, and Suffolk (SU; n = 10) lambs born February 2001. After weaning, lambs were supplemented with up to 1 kg corn/soybean meal while grazing bermudagrass or ryegrass. From birth to weaning, average daily gain (ADG) was greatest for DO followed by KA and SC lambs. Live weights were greater for SU than hair breed lambs. Carcasses from SU lambs were heavier than all other breed-types; yet, fat thickness and resulting yield grades of KA carcasses were greater than all other breeds. Longissimus thoracis (LT) areas of DO and SU were greater than that from KA or SC carcasses. Kidney fat weights and percentages of internal fat were greater from KA and SC than from DO and SU carcasses. Conformation scores for DO and SU carcasses were higher, resulting in higher quality grades than SC carcasses, with KA receiving intermediate scores. Cooked chops from SU had higher shear force values than chops from the hair breeds. Results from this study indicate that ADG, carcass muscularity and quality were similar between Dorper and Suffolk lambs, and, although fatter, carcass muscularity of KA was similar to that of DO lambs.