 |
Small Ruminant
Abstracts |
Nutritional and breed effects on carcass traits of Katahdin crossbred lambs
D.J. Jackson1, N.C. Whitley2, J.W. Lemaster3, and S. Schoenian4
1Graduate Student, University of Maryland Eastern Shore, Princess Anne, MD 21853
2Research Animal Scientist, University of Maryland Eastern Shore, Princess Anne, MD 21853
34-H Animal Science Specialist, University
of Maryland Extension, College Park, MD
4Sheep and Goat Specialist, University
of Maryland Extension, Western Maryland Research & Education
Center, Keedysville, MD 21756
At weaning, 43 Suffolk-(SK), Texel-(TK), and Dorper-(DK) sired Katahdin crossbred lambs were randomly removed from pasture and placed in a feedlot (GF), while 125 TK, SK, and DK lambs remained on pasture (PF) to determine the effects of feeding regime on carcass traits. At an average BCS of 2.8 (1-5 scale with 1=emaciated and 5=obese), 5 lambs/breed from both GF (134 ± 1.2d of age) and PF (153 ± 1.5d of age) were slaughtered to collect carcass data. The PF lambs had greater (P < 0.05) transport BW loss (-1.9 vs -1.0 ± 0.1 kg) and greater (P < 0.01) empty digestive tract weight (EDT; 5.3 vs 3. 6± 0.1kg), dressing percentage (50.7 vs 46.7 ± 0.7%), LEA (17.9 vs 16.0 ± 0.5 cm2, leg circumference (85.5 vs 77.5 ± 1.4cm), carcass length (103 vs 98.2 ± 0.8cm) and retail cut weights (14.5 vs 13.2 ± 0.3 kg) compared to GF lambs. DK lambs had the lowest (P < 0.01) pluck and retail weights (1.8 ± 0.1 and 13.1 ± 0.3kg, respectively) when compared to SK (2.1 ± 0.1 and 14.2 ± 0.3 kg, respectively) and TK (2.0 ± 0.1 and 14.3 ± 0.3kg, respectively) lambs. EDT, hot and cold carcass weights were lower (P < 0.05) in DK lambs (4.3 ± 0.1, 19.0 ± 0.5, and 18.7 ± 0.4 kg, respectively) than SK lambs (4.8 ± 0.1, 20.8 ± 0.5, and 20.3 ± 0.4kg, respectively) while TK lambs (4.4 ± 0.1, 20.3 ± 0.5, and 19.9 ± 0.4 kg, respectively) were intermediate. SK lambs had longer (P < 0.05; 107 ± 0.8cm) carcasses than TK (97.8 ± 0.8cm) and DK (97.1 ± 0.8cm) lambs. DK lambs (3.6 ± 0.3 mm) had greater (P < 0.05) back fat than TK lambs (2.4 ± 0.3 mm) while SK lambs (3.0 ± 0.3 mm) were intermediate. LEA was largest (P < 0.01) in TK (18.3 ± 0.65 cm2) lambs compared to both DK (16.3 ± 0.65 cm2) and SK lambs (16.4 ± 0.65 cm2). In addition, the carcasses from TK lambs received the highest (P < 0.05) quality grades and CIE L* and hue angle values and SK lambs had the highest (P < 0.05) mechanical shear force values. Overall, PF lambs had more muscle mass than their GF counterparts when slaughtered at a similar BCS, and sire breed had differential effects on carcass traits.
This abstract was presented at the Annual meeting of the Southern Section of the American Society of Animal Science in Mobile, Alabama in February 2007.