Skip to main content
ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #146182
Title: GENETIC CORRELATIONS FOR LITTER WEIGHT WEANED WITH REPRODUCTION AND WOOL CHARACTERISTICS IN RAMBOUILLET, COLUMBIA, TARGHEE AND POLYPAY SHEEP

Author
item Hanford, Kathryn
item Van Vleck, Lloyd
item Snowder, Gary

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2003
Publication Date: 7/1/2003
Citation: Hanford, K.J., Van Vleck, L.D., Snowder, G.D. 2003. Genetic correlations for litter weight weaned with reproduction and wool characteristics in Rambouillet, Columbia, Targhee and Polypay sheep [abstract]. Journal of Animal Science 81(Suppl. 1):68.

Interpretive Summary:

Technical Abstract: Genetic correlations between litter weight weaned (LW) and litter size born (NB), litter size weaned (NW), fleece weight (FW), fleece grade (FG), and staple length (SL) were estimated from Rambouillet (RAM), Columbia (COL), Targhee (TAR), and Polypay (POL) data collected from 1950 to 1998 at the U.S. Sheep Experiment Station, Dubois, ID. Records ranged from 8,313 to 39,816 for LW; 9,081 to 44,211 for NB and NW; 8,872 to 39,820 for FW and FG; and 1805 to 3574 for SL. Estimates of direct heritability with single-trait animal models using REML ranged from 0.07 to 0.09 for LW, 0.08 to 0.10 for NB, 0.03 to 0.07 for NW, 0.50 to 0.66 for FW, 0.16 to 0.41 for FG, and 0.56 to 0.76 for SL. Estimates of the genetic correlation between LW and NB were similar for RAM, COL and TAR breeds (0.59, 0.68, and 0.62, but was 0.05 for POL. The low correlation for POL may be due to generally restricting ewes to rearing only 2-3 lambs. The estimate of genetic correlation between LW and NW was close to one for all breeds. Estimates of the genetic correlations between LW and both FW and FG were near zero for all breeds, except RAM (0.12 for FW and -0.19 for FG). Estimates between LW and SL varied (0.07, -0.19, 0.10, and -0.17 for RAM, COL, TAR, and POL). Litter weight weaned is often used as an overall measure of range ewe productivity. These results suggest that selection for LW would result in neutral or favorable correlated responses except for a decrease in FG for RAM and decreases in SL for COL and POL. Decreases in FG and SL would have a minimal economic impact because of the small genetic correlations and because increased LW should offset decreases in FG and SL under today's market prices.