|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/14/2000
Publication Date: 3/1/2001
Citation: Hanford, K.J., Van Vleck, L.D., Snowder, G.D. 2001. Genetic parameter estimates for prolificacy, growth and fleece characteristics in Polypay sheep [abstract]. Journal of Animal Science 78(Suppl. 1)31. Interpretive Summary: No interpretive summary is required.
Technical Abstract: Heritabilities and genetic correlations for prolificacy, growth and fleece traits were calculated from Polypay data collected from 1977 to 1998. Number of records ranged from 8,313 to 9,081, 11,104 to 11,896, 1,805 to 8,872 for prolificacy, growth and fleece traits. Direct heritability estimates from single trait animal model analyses using REML were .11 for number lambs born (NB), .02 for number lambs weaned (NW), .05 for litter w at weaning (LW); .17 for birth wt (BW), .18 for 120 day wt (WW), .68 for fleece grade (FG), .36 for fleece wt (FW) and .76 for staple length (SL). Maternal heritability estimates were .20 for BW and .07 for WW. Estimates of genetic correlations between prolificacy traits were positive (.40 for NB-NW, .19 for NB-LW, .91 for NW-LW). Between BW and WW both the direct and maternal correlations were positive (.57 for direct and .48 for maternal). FG was negatively correlated with both FW (-.37) and SL (-.70), and FW was positively correlated with SL (.65). Estimates of genetic correlations wer low between the growth traits and NB and NW (.10, .24, .00, .07 for NB-BW, NB-WW, NW-BW, and NW-WW), and moderate between the growth traits and LW (.35 with BW and .74 with WW). FW was negatively correlated with NB (-.26) and NW (-.05), and was positively correlated with LW (.19). FG was positively correlated with the prolificacy traits (.09, .34, .04 for NB, NW, and LW), and SL was negatively correlated with the prolificacy traits (-.05, -.35, -.17 for NB, NW, and LW). Growth and fleece traits were positively correlated, except for the correlation between BW and FG, which was negatively correlated (.54, -.03, .17, .18, .03, .02 for BW-FW, BW-FG, BW-SL, WW-FW, WW-FG, and WW-SL).