Evaluation of Columbia, USMARC- Composite, Suffolk, and Texel Rams - - PowerPoint PPT Presentation
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
USDA, ARS, U.S. Sheep Experiment Station Dubois, ID
Virginia Tech, Blacksburg
1.30 1.35 1.40 1.45 1.50 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
11.7 11.6 12.1 11.6 73.4 72.9 76.3 70.7 53.7 52.4 60.5 48.8 20 40 60 80 100 120 140 160 Columbia Composite Suffolk Texel Body weight, lb Sire breed Birth wt Pre-weaning gain Postweaning gain
138.8 131.3 148.9 131.1
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
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 90 d postweaning 110 pounds 132 pounds Ultrasound backfat thickness, in Columbia Composite Suffolk Texel
YG 3/4 YG 1/2 YG 2/3
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
0.00 0.20 0.40 0.60 0.80 1.00 Age-constant backfat Wt-constant backfat Age-constant body wall Wt-constant body wall Carcass backfat or body wall thickness, in Columbia Composite Suffolk Texel
YG 2/3
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
2.00 2.10 2.20 2.30 2.40 2.50 2.60 2.70 90 d postweaning 132 pounds 0.25 inches backfat
Ultrasound loin muscle area, in2 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
2.25 2.30 2.35 2.40 2.45 2.50 2.55 2.60 2.65 2.70 Age-Constant Wt-constant
Carcass loin muscle area, in2 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
80 90 100 110 120 90 d postweaning 132 pounds 0.25 inches backfat
Relative value of gain:feed ratio, %
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
0.00 5.00 10.00 15.00 20.00 25.00 90 days 132 pounds 0.25 inches backfat
Residual feed intake, pounds
Columbia Composite Suffolk Texel Columbia-sired lambs required over 15 lb more feed than expected based on
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
0.00 0.50 1.00 1.50 2.00 2.50 3.00 90 days 132 pounds 0.25 inches backfat
Residual gain, lb
Columbia Composite Suffolk Texel Suffolk-sired lambs gained 2+ lb more than expected based on their observed body wt and feed intake
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.
10 20 30 40 Gain:feed (scaled) RFI (inverted) RNG (scaled) Net returns, $
“Feed efficiency” measurement
Columbia Composite Suffolk Texel
Relative efficiency of Texel vs. Suffolk is different for RFI than for
Yield Grade / Backfat Thickness (in) Carcass wt, lb 1 (< 0.16) 2 (0.16-0.26) 3 (0.26-0.36) 4 (0.36-0.46) 5 (>0.46) <55
55-65
65-75 75-85
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?
Carcass wt, lb Yield Grade / Backfat Thickness (in) 1 (< 0.16) 2 (0.16-0.26) 3 (0.26-0.36) 4 (0.36-0.46) 5 (>0.46) <55
55-65
65-75 75-85