The evolutionary potential of natural populations to adapt to anthropogenic threats critically depends on whether there exists additive genetic variation for tolerance to the threat. A major problem for water-dwelling organisms is chemical pollution, and among the most common pollutants is 17α-ethinylestradiol (EE2), the synthetic estrogen that is used in oral contraceptives and that can affect...

Estimates of genetic parameters resulting from three different models for birth weight, weaning weight, yearling weight and total gain were compared. Data consisted of 823 Holstein-Friesian animals progenies of 25 sires and 459 dams in a single herd. The MTDFREML programs were used to estimate heritabilities, predicted transmitting abilities (PTA) and genetic correlations. The three models comp...

The aim of the present study was to estimate (co)variance components and corresponding genetic parameters for birth weight (BW), weaning weight (WW), 6-month weight (W6), 9-month weight (W9), average daily gain from birth to weaning (WWDG), average daily gain from weaning to 6 months (W6DG) and average daily gain from 6 months to 9 months (W9DG) for a nucleus flock of Iranian Makooei sheep. Gen...

An experiment involving crosses among selection and control lines was conducted to partition direct and maternal additive genetic response to 20 yr of selection for 1) weaning weight (WWL), 2) yearling weight (YWL), and 3) an index of yearling weight and muscle score (IXL). Maternal response was estimated from reciprocal crosses among unselected sires and dams of control (CTL) and the selection...

genetic analysis of growth traits including body weight recorded at birth (bwt), 3 (3bwt), 6 (6bwt), 9 (9bwt) and 12 (12bwt) months of age was carried out using 4107 records on raieni cashmere goats born from 206 sires and 1402 dams, during years 1992 to 2006. the records were collected from a resource flock in baft research station, situated in kerman province, iran. the importance of addition...

Teaching, research, and herd breeding applications may require calculation of breed additive contributions for direct and maternal Brazilian Journal of Genetics Calculation of breed direct and maternal ... http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-845519... 2 of 14 5/2/2008 1:54 PM genetic effects and fractions of heterozygosity associated with breed specific direct and mater...

Variances and covariances for birth weight, gain from birth to weaning (ADG), and 205-d weight were obtained from a sire-dam model and a sire-maternal grandsire model for a herd of Angus and a herd of Hereford cattle. Estimates of direct additive genetic variance (sigma 2A), maternal additive genetic variance (sigma 2M), covariance between direct and maternal additive genetic effects (sigma AM)...

the objective of this study was to investigate the effect of principal components (pc) of the regression coefficients (co)variance matrix on the lactation curve, and on the formation of selection index to modify the curve, based on these pc’s, and as well to estimate additive genetic and phenotypic variances and heritability of the constructed selection index. lactation period of 301 d (5-305) ...

Data from the slaughter of 24,001 chickens that were part of a selection program for the production of commercial broilers were used to estimate genetic trend for absolute carcass (CW), breast meat (BRW), and leg (LW) weights, and relative carcass (CY), breast meat (BRY), and leg (LY) weights. The components of (co)variance and breeding values of individuals were obtained by the restricted maxi...