|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2001
Publication Date: 3/1/2001
Citation: Hanford, K.J., Snowder, G.D., Van Vleck, L.D. 2001. Genetic parameter estimates for prolificacy, growth and wool characteristics of Rambouillet sheep [abstract]. Journal of Animal Science 79(Suppl. 2):71.
Interpretive Summary: No interpretive summary is required.
Technical Abstract: Genetic parameters for prolificacy, growth and wool traits were estimated from Rambouillet data collected (1950-1998) at US Sheep Experiment Station, Dubois, ID. Records ranged from 39,816 to 44,211, 34,114 to 35,604, 3,574 to 39,821 for prolificacy, growth and wool traits. Heritability estimates from single trait animal model analyses using REML were .09 for litter size eat birth (LB), .06 for litter size at weaning (LW), .09 for litter weight weaned (LWW), .27 for birth weight (BW), .20 for weaning weight (WW), .16 for fleece grade (FG, visual spinning count), .51 for fleece weight (FW) and .58 for staple length (SL). Maternal heritability estimates were .19 for BW and .10 for WW. Estimates of genetic correlations among prolificacy traits were positive (.76 for LB-LW, .72 for LB-LWW, .95 for LW-LWW). Between BW and WW both direct and maternal genetic correlations were positive (.60 for direct and .36 for maternal). FG was negatively correlated genetically with both FW (-.47) and SL (-.52); FW was positivel correlated with SL (.46). Estimates of genetic correlations between BW and prolificacy traits were .24, .00, .37 for LB, LW, and LWW and between WW and prolificacy traits were .49, .56, .64 for LB, LW, and LWW. Estimated genetic correlations were small between fleece characteristics and prolificacy traits: for FW (-.08, -.04, .09), for FG (-.11, -.10, -.11) and for SL (-.16, -.04, -.07) with LB, LW and LWW, respectively. Growth traits were positively correlated genetically with FW (.21, .27 for BW and WW); negatively correlated with FG (-.15, -.14 for BW and WW) and positively correlated with SL (.14, .09 for BW and WW). These estimates are needed for multiple-trait, multi-flock genetic evaluations and for deriving selection indexes to optimize profitability of genetic selection.