Evaluation of Columbia, USMARC- Composite, Suffolk, and Texel Rams as Terminal Sires in an Extensive Rangeland Production System Gregory S. Lewis USDA, ARS, U.S. Sheep Experiment Station Dubois, ID David R. Notter Virginia Tech, Blacksburg
Numbers of lambs weaned per ewe mated for Rambouillet ewes mated to Columbia, Composite, Suffolk, and Texel rams. Differences among the sire breeds are not statistically significant. 1.50 1.45 1.40 1.35 1.30 Lambs weaned per ewe lambing Lambs weaned per ewe mated Columbia Composite Suffolk Texel
Survival functions from birth to weaning for lambs sired by Columbia, Composite, Suffolk, and Texel rams, and adjusted to a lamb born in 2007 to a 3-yr-old ewe. Sire breeds that do not share a common letter differed ( P < 0.05) for survival rate.
Body weights at birth, weaning, and 90 days postweaning for lambs sired by Columbia, Composite, Suffolk, and Texel rams. Values within shaded columns are birth weights and gains during the pre- and postweaning periods 160 138.8 131.3 148.9 131.1 140 120 60.5 53.7 52.4 48.8 Body weight, lb 100 80 60 76.3 73.4 72.9 70.7 40 20 11.7 12.1 11.6 11.6 0 Columbia Composite Suffolk Texel Sire breed Birth wt Pre-weaning gain Postweaning gain
Ultrasound backfat thickness for ewe and wether lambs sired by Columbia, Composite, Suffolk, and Texel rams at 90 days postweaning, or 110 or 132 pounds live weight . Horizontal lines designate boundaries between Yield Grades 2 and 3 or 3 and 4 0.45 0.40 Ultrasound backfat thickness, in YG 3/4 0.35 0.30 YG 2/3 0.25 0.20 YG 1/2 0.15 0.10 0.05 0.00 90 d postweaning 110 pounds 132 pounds Columbia Composite Suffolk Texel
Carcass backfat and body wall thicknesses for wether lambs sired by Columbia, Composite, Suffolk, and Texel rams at age- or weight-constant endpoints. Horizontal line is the boundary for carcass backfat between Yield Grades 2 and 3 1.00 Carcass backfat or body wall thickness, in 0.80 0.60 0.40 YG 2/3 0.20 0.00 Age-constant backfat Wt-constant backfat Age-constant body Wt-constant body wall wall Columbia Composite Suffolk Texel
Ultrasound loin muscle area for ewe and wether lambs sired by Columbia, Composite, Suffolk, and Texel rams at 90 days postweaning, 132 pounds live weight, or 0.25 inches of backfat 2.70 2.60 Ultrasound loin muscle area, in 2 2.50 2.40 2.30 2.20 2.10 2.00 90 d postweaning 132 pounds 0.25 inches backfat Endpoint Columbia Composite Suffolk Texel
Carcass loin muscle area for wether lambs sired by Columbia, Composite, Suffolk, and Texel rams at age- or weight-constant endpoints 2.70 2.65 Carcass loin muscle area, in 2 2.60 2.55 2.50 2.45 2.40 2.35 2.30 2.25 Age-Constant Wt-constant Endpoint Columbia Composite Suffolk Texel
Relative values for gain:feed ratio (overall average = 100; higher values indicate more efficient growth ) for lambs sired by Columbia, Composite, Suffolk, and Texel rams at 90 days postweaning, 132 pounds live weight, or 0.25 inches of backfat 120 Relative value of gain:feed ratio, % 110 100 90 80 90 d postweaning 132 pounds 0.25 inches backfat Columbia Composite Suffolk Texel
Residual feed intake for lambs sired by Columbia, Composite, Suffolk, and Texel rams at 90 days postweaning, 132 pounds live weight, or 0.25 inches of backfat. Low values are superior, and indicate that less feed was required given observed body weights and average daily gains 25.00 Columbia-sired lambs required over 15 lb more feed than expected based on Residual feed intake, pounds 20.00 observed body wt and growth rates 15.00 10.00 5.00 0.00 -5.00 -10.00 90 days 132 pounds 0.25 inches backfat Columbia Composite Suffolk Texel
Residual gain for lambs sired by Columbia, Composite, Suffolk, and Texel rams at 90 days postweaning, 132 pounds live weight, or 0.25 inches of backfat. Higher values are superior, and indicate more rapid gains at similar body weights and levels of feed intake 3.00 Suffolk-sired lambs gained 2+ lb more 2.50 than expected based on their observed 2.00 body wt and feed intake 1.50 Residual gain, lb 1.00 0.50 0.00 -0.50 -1.00 -1.50 -2.00 90 days 132 pounds 0.25 inches backfat Columbia Composite Suffolk Texel
Alternative measures of feed efficiency intake for lambs sired by Columbia, Composite, Suffolk, and Texel rams at 90 days on test. Values have been adjusted to equalize the scales, and values of RFI are inverted. Therefore, positive values are always superior. 40 Relative efficiency of Texel vs. “Feed efficiency” measurement Suffolk is different for RFI than for 30 other estimates of efficiency 20 10 0 -10 -20 Gain:feed (scaled) RFI (inverted) RNG (scaled) Net returns, $ Columbia Composite Suffolk Texel
Cumulative residual feed intake across days on study by lamb sire breed
Selling on a Lamb Pricing Grid Yield Grade / Backfat Thickness (in) Carcass wt, 1 2 3 4 5 lb (< 0.16) (0.16-0.26) (0.26-0.36) (0.36-0.46) (>0.46) <55 - $15 / cwt -$35 / cwt - $5 / cwt 55-65 + $12/cwt -$10 / cwt -$30 / cwt 65-75 Base 75-85 Base 85 - $20/cwt - $30 /cwt - $50 /cwt
Selling on a Lamb Pricing Grid USSES Terminal Sired Lambs: 4 sire breeds (CO, C3, SU, TX) mated to Rambouillet ewes. Harvest lambs at wts between 120 and 150 lb. Where do they fit the Grid? Yield Grade / Backfat Thickness (in) Carcass wt, 1 2 3 4 5 lb (< 0.16) (0.16-0.26) (0.26-0.36) (0.36-0.46) (>0.46) <55 - $15 / cwt -$35 / cwt - $5 / cwt (1%) 55-65 + $12/cwt -$10 / cwt -$30 / cwt 65-75 Base (70%) (4%) (23%) 75-85 Base (2%) 85 - $30 /cwt - $50 /cwt - $20/cwt
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