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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #121009
Title: MODELS FOR BIRTH, WEANING AND FLEECE WEIGHTS, AND LITTER SIZE FOR A POPULATION OF TARGHEE SHEEP

Author
item Van Vleck, Lloyd
item Snowder, Gary
item HANFORD, K. - UNIV. OF NEBRASKA-LINCOLN

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2001
Publication Date: 3/1/2001
Citation: Van Vleck, L.D., Snowder, G.D., Hanford, K.J. 2001. Models for birth, weaning and fleece weights, and litter size for a population of Targhee sheep [abstract]. Journal of Animal Science 79(Suppl. 1):70.

Interpretive Summary: No interpretive summary is required.

Technical Abstract: Models (17) were compared for birth weight of 33,994 lambs recorded at USSES (1950-1998). Intent was to estimate fractions of variance due to cytoplasmic line (c-2; 892) and sire-cytoplasmic line interaction (sc-2; 17,557). Basic model included direct genetic (fractional variance, a-2; 35,684), maternal genetic (m-2, with correlation r-am), and maternal permanent environmental (p-2; 8,418) effects. Model with sc-2 was significantly better than basic model with and without c-2. When other random effects were added, sc-2 became zero. Significant effects were associated with dam-year (dy-2; 24,801), sire-dam (sd-2; 23,924) and dam- number born (dn-2; 12,944) interaction effects. Estimates were: (a-2, .24; m-2, .19; r-am, .11; p-2, .05; c-2, .00; dn-2, .04; dy-2, .06; sd-2, .05; sc-2, .00). Estimates for a-2, m-2, and r-am were same for all models. Estimate of p-2 changed when other effects were added. Largest estimates for non-genetic effects were: p-2, .08; c-2, .00; dy-2, .13; sd-2, .11; an sc-2, .04. For weaning weight (120-d, n = 32,715) estimates for effects added to basic model were near zero (a-2, .18; m-2, .12; r-am, -.01; p-2, .06). For number born (NB, n = 37,020) and fleece weight (FW, n = 36,197), animal permanent environmental effects were added to the model (ap-2, 9,871 and 9,760) and r-am was dropped. For neither trait did effects beyond basic model have large variances. For NB, non-zero estimates with full model were: (a-2, .10; ap-2, .01; dy-2, .02; sc-2, .01) and for FW were: (a-2, .54; m-2, .02; ap-2, .02; dy-2, .04 and sc-2, .02). Cytoplasmic effects were not important. Addition of unusual effects to model did not change estimates for basic model. Although some effects were significant, especially for BW, effects on genetic evaluations are likely small.