Estimation of genetic trends for weaning weight and teat number in Iberian pigs using mixed model methodology

1993 ◽  
Vol 33 (3-4) ◽  
pp. 239-251 ◽  
Author(s):  
F. Béjar ◽  
M.C. Rodríguez ◽  
M.A. Toro
Keyword(s):  
Mixed Model ◽  
Weaning Weight ◽  
Teat Number ◽  
Mixed Model Methodology ◽  
Genetic Trends

EVALUATION OF BEEF SIRES FOR MATERNAL GENETIC EFFECTS ON WEANING WEIGHT AND MEASUREMENT OF GENETIC TRENDS

1983 ◽  
Vol 63 (2) ◽  
pp. 279-283 ◽  
Author(s):  
G. H. CROW ◽  
W. E. HOWELL
Keyword(s):  
Variance Components ◽  
Mixed Model ◽  
Error Variance ◽  
Genetic Effects ◽  
Genetic Trend ◽  
Linear Unbiased Prediction ◽  
Weaning Weight ◽  
Best Linear Unbiased ◽  
Maternal Grandsire ◽  
Genetic Trends

Procedures for evaluating beef sires for maternal genetic effects for weaning weight were developed and used in the calculation of genetic trends. Using the maternal grandsire (MGS) and error variance components, predicted differences (PDs) of MGSs for parity one daughter performance were calculated using Record of Performance data from the Angus, Charolais and Hereford breeds. Best linear unbiased prediction (BLUP) methods were used with a mixed model which included herd-year and MGS effects. The average number of daughter records per MGS was 5.44, 5.26 and 5.12 for Angus, Hereford and Charolais, respectively. As a result of these small numbers of daughter records, the PDs of most MGSs had very large standard errors of prediction. Weighted averages of MGS PDs for each breed in each of the 5 years from 1975 to 1979 were calculated to determine if there was any genetic trend in MGS PDs. There were small trends evident but not sufficient to indicate that any selection pressure was being exerted on maternal ability. Key words: Beef sire evaluation, maternal effects, genetic trends

scholarly journals Selection of coffee progenies for resistance to nematode Meloidogyne paranaensis in infested area

2014 ◽  
Vol 14 (2) ◽  
pp. 94-101 ◽  
Author(s):  
Sonia Maria Lima Salgado ◽  
Juliana Costa de Rezende ◽  
José Airton Rodrigues Nunes
Keyword(s):  
Genetic Variability ◽  
Coffea Arabica ◽  
Mixed Model ◽  
High Rate ◽  
Germplasm Bank ◽  
Genotypic Association ◽  
Coffee Plants ◽  
Plagiotropic Branches ◽  
Mixed Model Methodology ◽  
Selection Of

The purpose of this study was to select Coffea arabica progenies for resistance to M. paranaensis in an infested coffee growing area using Henderson's mixed model methodology. Forty-one genotypes were selected at the Coffee Active Germplasm Bank of Minas Gerais, and evaluated in regard to stem diameter, number of plagiotropic branches, reaction to the nematode, and yield per plant. There was genetic variability among the genotypes studied for all the traits evaluated, and among the populations studied for yield and reaction to the nematode, indicating possibilities for obtaining genetic gains through selection in this population. There was high rate of genotypic association between all the traits studied. Coffee plants of Timor Hybrid UFV408-01 population, and F3 progenies derived from crossing Catuaí Vermelho and Amphillo MR 2161 were the most promising in the area infested by M. paranaensis.

scholarly journals Plant selection in F2 segregating populations of papaya from commercial hybrids

2012 ◽  
Vol 12 (3) ◽  
pp. 191-198 ◽  
Author(s):  
Eder Jorge Oliveira ◽  
Gilberto de Andrade Fraife Filho ◽  
Juan Paulo Xavier de Freitas ◽  
Jorge Luiz Loyola Dantas ◽  
Marcos Deon Vilela de Resende
Keyword(s):  
Genetic Parameters ◽  
Mixed Model ◽  
Soluble Solids ◽  
Fruit Firmness ◽  
Plant Selection ◽  
F2 Population ◽  
The Common ◽  
Mixed Model Methodology ◽  
Fruit Diameter ◽  
Selection Of

The objective of this paper was to estimate the genetic parameters and additive genetic values in segregating populations of papaya using the mixed model methodology. Two F2 populations from Tainung and Calimosa hybrids were evaluated. The experimental design was an augmented block with four replicates, and Golden and Calimosa cultivars were the common treatment. Estimates of individual heritability were high for fruit length (FL) and weight (FW), moderate for fruit diameter (FD), and low for total soluble solids (TSS) and fruit firmness (FF). Considering FF and TSS as main traits for selection, genotypes of Calimosa-F2 population showed better performance to FF, but worse concerning TSS. It was selected 18.3% and 24.6% of plants from Tainung-F2 and Calimosa-F2 populations, respectively. Negative correlation between TSS and FF was not able to reduce the genetic gains. The segregating populations from Calimosa hybrid are more promising for the selection of papaya lines.

WEIGHTED AVERAGES OF SIRE PROGENY TESTS FOR GROWTH TRAITS IN RECORD OF PERFORMANCE BEEF HERDS

1981 ◽  
Vol 61 (1) ◽  
pp. 35-44 ◽  
Author(s):  
L. R. SCHAEFFER ◽  
J. A. ERIKSSON ◽  
J. W. WILTON
Keyword(s):  
Growth Traits ◽  
Monitoring Program ◽  
Weighted Average ◽  
Test Program ◽  
Weaning Weight ◽  
Declining Enrollment ◽  
Beef Herds ◽  
Progeny Tests ◽  
Annual Trends ◽  
Genetic Trends

Growth records of 281 744 calves born from 1971 to 1978 were used to calculate annual phenotypic and genetic trends for weaning weight and yearling weight. Genetic trends were computed as the weighted average of sire-transmitting abilities obtained from the Record of Performance National Beef Sire Monitoring Program. There were no significant differences between the genetic trends of all calves vs. calves which made a yearling weight for either weaning weight or yearling weight. Annual trends were positive for Angus, Hereford, and Shorthorn breeds, and were negative for Charolais, Limousin, Maine-Anjou and Simmental breeds. The interpretation of annual trends was complicated by the declining enrollment of herds on the test program which could have artificially altered the averages.

scholarly journals Evaluation of Phenotypic and Genetic Trends in Weaning Weight in Angus and Hereford Populations in Virginia1

1987 ◽  
Vol 64 (5) ◽  
pp. 1349-1361 ◽  
Author(s):  
K. Nadarajah ◽  
D. R. Notter ◽  
T. J. Marlowe ◽  
A. L. Eller
Keyword(s):  
Weaning Weight ◽  
Genetic Trends

ALTERNATIVE PROGENY TESTING PROGRAMS FOR WEANING WEIGHT AND EASE OF CALVING IN BEEF CATTLE

1980 ◽  
Vol 60 (3) ◽  
pp. 609-620 ◽  
Author(s):  
G. F. S. HUDSON ◽  
L. R. SCHAEFFER ◽  
J. W. WILTON
Keyword(s):  
Beef Cattle ◽  
Standard Error ◽  
Design Patterns ◽  
Mixed Model ◽  
Herd Size ◽  
Progeny Testing ◽  
Weaning Weight ◽  
Calving Ease ◽  
Model Equations ◽  
Average Standard Error

Progeny test programs were characterized by numbers of young bulls, successful matings (conceptions) per young bull, herds in which each young sire was used, proven bulls used as reference sires and herd size. Matings to reference sires were calculated as a percentage of the number of young sire matings. Designs were simulated and mixed-model equations formed and added to equations obtained from the Canadian ROP program for years 1971–1978. The average standard error of prediction (SEP) of young bulls was used for comparing designs. Increasing matings per young sire decreased SEP curvilinearly. The curvilinearity was greater when either herd size or herds per young sire was low. Increasing herd size and herds per young sire improved connectedness between sires and reduced SEP. Number of young sires affected SEP only when fewer than 10 bulls were sampled. Number of young sire matings were more important in reducing SEP than percent reference sire matings. If number of young sire matings was adequate to achieve a desired level of SEP, 10% reference sire matings were sufficient. The number of reference sires used did not affect SEP. Design patterns affected SEP of weaning weight (h2 = 0.25) and calving ease (h2 = 0.10) similarly. SEP was not affected by the number of proven sires in a breed (Maine Anjou, 133 sires or Blonde d’Aquitaine, 39 sires) or by the connectedness between proven sires.

scholarly journals Comparison of growth curves of two genotypes of dairy goats using nonlinear mixed models

2013 ◽  
Vol 152 (5) ◽  
pp. 829-842 ◽  
Author(s):  
J. G. L. REGADAS FILHO ◽  
L. O. TEDESCHI ◽  
M. T. RODRIGUES ◽  
L. F. BRITO ◽  
T. S. OLIVEIRA
Keyword(s):  
Random Effects ◽  
Growth Curve ◽  
Mixed Model ◽  
Growth Curves ◽  
Growth Patterns ◽  
Dairy Goat ◽  
Residual Variance ◽  
Nonlinear Mixed Model ◽  
Error Structure ◽  
Mixed Model Methodology

SUMMARYThe objective of the current study was to assess the use of nonlinear mixed model methodology to fit the growth curves (weightv.time) of two dairy goat genotypes (Alpine, +A and Saanen, +S). The nonlinear functions evaluated included Brody, Von Bertalanffy, Richards, Logistic and Gompertz. The growth curve adjustment was performed using two steps. First, random effectsu1,u2andu3were linked to the asymptotic body weight (β1), constant of integration (β2) and rate constant of growth (β3) parameters, respectively. In addition to a traditional fixed-effects model, four combinations of models were evaluated using random variables: all parameters associated with random effects (u1,u2andu3), onlyβ1andβ2(u1andu2), onlyβ1andβ3(u1andu3) and onlyβ1(u1). Second, the fit of the best adjusted model was refined by using the power variance and modelling the error structure. Residual variance ($\sigma _e^2 $) and the Akaike information criterion were used to evaluate the models. After the best fitting model was chosen, the genotype curve parameters were compared. The residual variance was reduced in all scenarios for which random effects were considered. The Richards (u1andu3) function had the best fit to the data. This model was reparameterized using two isotropic error structures for unequally spaced data, and the structure known in the literature as SP(MATERN) proved to be a better fit. The growth curve parameters differed between the two genotypes, with the exception of the constant that determines the proportion of the final size at which the inflection point occurs (β4). The nonlinear mixed model methodology is an efficient tool for evaluating growth curve features, and it is advisable to assign biologically significant parameters with random effects. Moreover, evaluating error structure modelling is recommended to account for possible correlated errors that may be present even when using random effects. Different Richard growth curve parameters should be used for the predominantly Alpine and Saanen genotypes because there are differences in their growth patterns.

scholarly journals Estimates of genetic parameters and genetic trends for reproductive traits and weaning weight in Tabapuã cattle1,2

2015 ◽  
Vol 93 (11) ◽  
pp. 5175-5185 ◽  
Author(s):  
P. A. Bernardes ◽  
D. A. Grossi ◽  
R. P. Savegnago ◽  
M. E. Buzanskas ◽  
I. Urbinati ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Reproductive Traits ◽  
Weaning Weight ◽  
Genetic Trends
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