Effects of parental age and sampling method on response to index selection in Tribolium castaneum

1983 ◽  
Vol 25 (1) ◽  
pp. 47-52 ◽  
Author(s):  
D. L. Patterson ◽  
G. W. Friars ◽  
I. McMillan
Keyword(s):  
Variance Components ◽  
Sampling Method ◽  
Sampling Methods ◽  
Genetic Correlations ◽  
Pupal Weight ◽  
Parental Age ◽  
Larval Weight ◽  
Selection Experiments ◽  
Two Generations ◽  
Selection For

Two generations of individual selection on the basis of an index incorporating the 13th day larval weight and pupal weight were carried out using Triboliumcastaneum. The experimental design consisted of two sampling methods by three parental ages and was repeated three times concurrently (three sets). Eight offspring for each of 10 families per set were measured. Heritabilities and phenotypic and genetic correlations for larval and pupal weights were estimated using variance components. Age of parents had an effect on response to selection for total merit. Offspring of older parent stocks had heavier larval weight. Sampling parents from one subpopulation versus sampling from a group of subpopulations had no consistent effect on total merit. Although the overall effect of set was not significant, interactions of set with sampling method and parental age were significant, indicating that control of these factors might reduce among replicate variation commonly seen in selection experiments.

scholarly journals Genetic parameters between somatic cell score and production traits for Holstein cattle in Southern Brazil

2020 ◽  
Vol 33 (1) ◽  
pp. 60-70
Author(s):  
Gabrieli S Romano ◽  
Luis Fernando B Pinto ◽  
Altair A Valloto ◽  
José-Augusto Horst ◽  
Victor B Pedrosa
Keyword(s):  
Somatic Cell ◽  
Milk Yield ◽  
Variance Components ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Milk Quality ◽  
Somatic Cell Score ◽  
Fat Percentage ◽  
Fat Yield ◽  
Selection For

Background: Somatic cell score is an important parameter to predict milk quality and health of cows. However, in countries like Brazil, this trait is still not selected on a large scale, and no genetic parameters are reported in the literature. Objective: To estimate the variance components and genetic parameters for somatic cell score, milk yield, fat yield, protein yield, fat percentage, and protein percentage in Holstein cows. Methods: Records from 56,718 animals were used to estimate variance components, heritability, and genetic correlations using a multi-trait animal model by the REML method. Results: The heritability estimates were 0.19 for somatic cell score, 0.22 for milk yield, 0.26 for fat yield, 0.18 for protein yield, 0.61 for fat percentage, and 0.65 for protein percentage. The estimates of genetic correlations among analyzed traits ranged from -0.50 to 0.82. Conclusion: The low heritability observed for somatic cell score indicates that selection for this trait should result in benefits related to animal health and milk quality, but only in the long term. The low correlation between productive traits and somatic cell score indicates that inclusion of somatic cell score in animal breeding programs does not interfere negatively with the genetic selection for milk yield or solids.Keywords: Holstein; genetic correlation; genetic parameters; heritability; mastitis; milk quality; milk yield; multi-trait model; somatic cell score; variance components.  Resumen Antecedentes: El conteo de células somáticas es un parámetro importante para predecir la calidad de la leche y la salud de las vacas. Sin embargo, en países como Brasil, esta característica aún no se selecciona a gran escala y no se reportan parámetros genéticos en la literatura. Objetivo: Estimar los componentes de varianza y parámetros genéticos para el conteo de células somáticas, producción de leche, producción de grasa, producción de proteína, porcentaje de grasa y porcentaje de proteína en vacas de la raza Holstein. Métodos: Se usaron registros de 56.718 animales para estimar los componentes de la varianza, heredabilidad y correlaciones genéticas usando un modelo animal multicaracterístico por medio del método REML. Resultados: Las estimaciones de heredabilidad fueron 0,19 para el conteo de células somáticas, 0,22 para la producción de leche, 0,26 para la producción de grasa, 0,18 para producción de proteína, 0,61 para el porcentaje de grasa y 0,65 para el porcentaje de proteína. Las estimaciones de correlación genética entre las características analizadas variaron entre -0,50 a 0,82. Conclusión: La baja heredabilidad encontrada para conteo de células somáticas demostró que la selección para esta característica podría resultar en beneficios para la salud animal y calidad de la leche, pero sólo a largo plazo. La baja correlación genética existente entre las características productivas y el conteo de células somáticas indica que la inclusión del conteo de células somáticas en programas de selección no interfiere negativamente en la selección genética para la producción de leche o sólidos.Palabras clave: calidad de leche; correlación genética; conteo de células somáticas; componentes de varianza; heredabilidad; Holstein; mastitis; modelo multicaracteristico; parametros geneticos; producción de leche; selección genetica. Resumo Antecedentes: O escore de células somáticas é um parâmetro importante para a predição da qualidade do leite, bem como para a saúde das vacas. No entanto, em alguns países como o Brasil, essa característica não é selecionada em larga escala e não há parâmetros genéticos disponíveis na literatura. Objetivo: Estimar os componentes de variância e parâmetros genéticos para o escore de células somáticas, produção de leite, produção de gordura, produção de proteína, porcentagem de gordura e porcentagem de proteína em vacas da raça Holandesa. Métodos: Foi utilizado um total de 56.718 animais para estimar os componentes de variância, herdabilidade e correlações genéticas, considerando-se o modelo animal multicaracterística por meio do método REML. Resultados: As estimativas de herdabilidade foram de 0,19 para o escore de células somáticas, 0,22 para a produção de leite, 0,26 para a produção de gordura, 0,18 para produção de proteína, 0,61 para a porcentagem de gordura e 0,65 para a porcentagem de proteína. As estimativas de correlação genética entre as características analisadas variaram entre -0,50 a 0,82. Conclusão: A baixa herdabilidade encontrada para o escore de células somáticas demonstrou que a seleção para esta característica poderá resultar em benefícios para a saúde animal e qualidade do leite, porém, somente a longo prazo. A baixa correlação genética existente entre as características produtivas e o escore de células somáticas demonstrou que a inclusão do escore de células somáticas em programas de seleção não causa interferência negativa na seleção genética para a produção de leite ou sólidos.Palavras-chave: componentes de variância; correlação genéticas; escore de células somáticas; herdabilidade; mastite; modelo multicaracterística; parâmetros genéticos; produção de leite; qualidade do leite; raça Holandesa; seleção genética.

COMPONENTS OF GROWTH IN GENETICALLY DIVERSE POPULATIONS OF TRIBOLIUM CASTANEUM

1969 ◽  
Vol 11 (4) ◽  
pp. 896-907 ◽  
Author(s):  
DuWayne C. Englert ◽  
A. E. Bell
Keyword(s):  
Tribolium Castaneum ◽  
Adult Emergence ◽  
Pupal Weight ◽  
Diverse Populations ◽  
Correlated Responses ◽  
Larval Weight ◽  
Developmental Patterns ◽  
Adult Weight ◽  
Total Growth ◽  
Selection For

The growth and developmental patterns of 19 genetically diverse populations of Tribolium castaneum were examined. Measurements were obtained on three primary traits (13-day larval weight, pupation time and pupal weight) and three secondary traits (number of larval molts, adult emergence time and adult weight). The populations were chosen on the basis of their previous selection histories. Selection for different primary traits produced profound effects upon the total growth and development complex.Genetic and environmental relationships between primary traits were estimated within each population, and a consistent asymmetry of correlated responses was observed to be determined by the direction of selection.Possible effects upon the disruption of an intricate balance of the three metamorphosis hormones (activation, molting and juvenile) through selection were postulated.

RESPONSE TO SELECTION FOR WEIGHT-PER-DAY-OF-AGE IN RAMBOUILLET AND ROMNELET SHEEP

1975 ◽  
Vol 55 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J. A. VESELY ◽  
H. F. PETERS
Keyword(s):  
Genetic Correlations ◽  
Response To Selection ◽  
Correlated Responses ◽  
Weaning Weight ◽  
Two Generations ◽  
Selection For ◽  
Heritability Estimates

Responses to selection for weight-per-day-of-age (WPDA) to about 170 days in Rambouillet and Romnelet sheep over 5 yr, comprising two generations, were measured by two methods. Correlated responses in weaning weight (WW) at about 100 days, and postweaning gain (PWG) for 70 days were also estimated. The estimates of annual genetic increases in WPDA were quite similar in both breeds and from both methods. The improvements of this trait in Rambouillet and Romnelet were estimated as 9.7 and 6.0 g/yr from method 1, and 9.1 and 7.8 g/yr from method II. Estimates of correlated responses in PWG obtained by both methods and in both breeds were close to expected estimates, but correlated responses in WW appeared to be overestimated. Heritability estimates for WPDA using paternal half-sibs were 0.20 for Rambouillet and 0.18 for Romnelet. All genetic correlations among the three traits were positive. Realized heritabilities for WPDA were 0.28 and 0.20 in Rambouillet and Romnelet by method I, and 0.26 in both breeds by method II.

scholarly journals Heritabilities and genetic correlations of lactational and daily somatic cell score with conformation traits in Polish Holstein cattle

2011 ◽  
Vol 56 (No. 5) ◽  
pp. 205-212 ◽  
Author(s):  
E. Ptak ◽  
W. Jagusiak ◽  
A. Żarnecki ◽  
A. Otwinowska-Mindur
Keyword(s):  
Somatic Cell ◽  
Variance Components ◽  
Genetic Correlations ◽  
Somatic Cell Score ◽  
Direct Selection ◽  
Linear Type ◽  
Holstein Friesian ◽  
Type Traits ◽  
Selection For ◽  
Friesian Cows

The objective of this study was to estimate heritabilities and genetic correlations of lactational and daily somatic cell scores with descriptive and linear type traits in Polish Holstein-Friesian cows. Data were: test-day somatic cell scores and conformation evaluations of 24 599 primiparous cows, daughters of 802 sires. Cows calved from 2006 to 2007. The lactational somatic cell score was calculated as the average of four test-day somatic cell scores at least. The daily somatic cell score was the test-day somatic cell score closest to the date of type evaluation. A multi-trait animal model was used to estimate genetic parameters. (Co)variance components were estimated by a Bayesian algorithm via Gibbs sampling. The heritability of lactational somatic cell score was 0.20 and it was much higher than that of daily somatic cell score (0.13). Heritabilities of type traits were high to moderate for height at rump (0.46), size (0.39), overall conformation score (0.30), two linear rump traits (0.28–0.29) and three linear teat traits (0.26–0.29). The genetic correlation between lactational and daily somatic cell scores was 0.84. In many cases, daily somatic cell score showed higher genetic correlations with type traits than lactational somatic cell score. Descriptive udder and feet and legs scores were genetically correlated negatively with both lactational (–0.22 and –0.20) and daily somatic cell scores (–0.28 and –0.33). Somatic cell traits were genetically correlated positively with rump angle (0.21 and 0.19) and negatively with fore udder height (–0.26 and –0.29), udder depth (–0.23 and –0.17) and central ligament (–0.14 and –0.16). Due to higher heritability, direct selection for lower lactational somatic cell score would be more effective than selection for lower daily somatic cell score. The magnitude of obtained heritabilities and the favourable genetic correlations indicate that the selection utilizing some type traits could improve the resistance to mastitis.

Resistance to nematode parasites in Merino sheep: correlation with production traits

1998 ◽  
Vol 49 (8) ◽  
pp. 1201 ◽  
Author(s):  
S. J. Eady ◽  
R. R. Woolaston ◽  
R. W. Ponzoni ◽  
R. P. Lewer ◽  
H. W. Raadsma ◽  
...  
Keyword(s):  
Variance Components ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Correlated Response ◽  
Production Traits ◽  
Merino Sheep ◽  
Nematode Parasites ◽  
Faecal Egg Count ◽  
Selection For ◽  
Fleece Weight

Merino sheep representing a range of bloodlines in resource flocks located across Australia were tested for resistance to gastro-intestinal nematodes. These flocks included the JB Pye Flock (Camden, NSW), Katanning Base Flock (Katanning, WA), Turretfield Merino Resource Flock (Rosedale, SA), and the CSIRO Finewool Flock (Armidale, NSW) and included a total of 328 sire groups. Resistance to nematodes was measured by faecal egg count (FEC). Data were also available for greasy and clean fleece weight (GFW and CFW, respectively), fibre diameter (FD), and body weight (BW) at a range of ages from weaning to 21 months. Variance components were estimated by restricted maximum likelihood, fitting an animal model and estimating covariances in a series of bivariate analyses. Phenotypic correlations between FEC0·33 and production traits were all close to zero ( –0·09–0·02). Genetic correlations between FEC0·33 and production traits were –0·20, –0·18, and –0·26 for weaning weight, 10-month BW, and 16-month BW, respectively; 0·21, –0·06, and 0·21 for 10-month GFW, 16-month GFW, and 21-month GFW; 0·21, –0·05, and 0·07 for 10-month CFW, 16-month CFW, and 21-month CFW; and –0·09, –0·12, and 0·04 for 10-month FD, 16-month FD, and 21-month FD. When estimates were pooled for all fleece traits and all BW traits, the genetic correlations between FEC0·33 and GFW, CFW, FD, and BW were 0·15, 0·10, –0·06, and –0·21, respectively. Using pooled estimates for CFW, FD, and BW, selection for a breeding objective based on production traits alone would lead to an unfavourable correlated response in FEC0·33 of approximately 1% per year.

EXPERIMENTAL INVESTIGATION OF ERRORS OF HERITABILITY ESTIMATES IN INDEX SELECTION

1979 ◽  
Vol 21 (3) ◽  
pp. 303-308 ◽  
Author(s):  
C. Y. Lin ◽  
I. Pevzner ◽  
G. W. Friars
Keyword(s):  
Experimental Investigation ◽  
Parameter Estimation ◽  
Tribolium Castaneum ◽  
Genetic Change ◽  
Pupal Weight ◽  
Index Selection ◽  
Selection Efficiency ◽  
Larval Weight ◽  
Estimation Errors ◽  
Selection For

Three generations of index selection for the combined genetic gain in 13-day larval and 21-day pupal weight were carried out in each of three replicates in Tribolium castaneum. Five indexes were constructed using differing levels of heritability for larval weight (0.9, 0.7, 0.5, 0.3 and 0.1). The effect of parameter estimation errors, involving larval weight, on the efficiency of index selection was thus evaluated experimentally. The results from this experiment confirmed the theoretical expectations that errors of parameter estimation would affect the efficiency of index selection. The present study further showed that the overestimation of the parameters would affect the selection efficiency more than the underestimation. The combined gain was found to be realized mainly through genetic change in pupal weight, a trait with lower heritability.

129 Genomic Relationship Between PRRSV Wild-type Infection and PRRSV Vaccination for Antibody Response and Reproductive Performance

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 18-18
Author(s):  
Leticia P Sanglard ◽  
Felipe Hickmann ◽  
Yijian Huang ◽  
Kent A Gray ◽  
Daniel Linhares ◽  
...  
Keyword(s):  
Antibody Response ◽  
Reproductive Performance ◽  
Genetic Correlations ◽  
Clinical Signs ◽  
Respiratory Syndrome Virus ◽  
Wild Type ◽  
Large White ◽  
Selection For ◽  
Indicator Trait ◽  
Type Infection

Abstract Immunoglobulin G antibody response, measured as sample-to-positive (S/P) ratio, to Porcine Reproductive and Respiratory Syndrome virus (PRRSV) has been proposed as an indicator trait for improved reproductive performance in PRRSV-infected purebred sows and PRRSV-vaccinated crossbred gilts. In this study, we investigated the genetic correlations (rg) of S/P ratio following a PRRSV outbreak and PRRSV-vaccination with performance in non-exposed and PRRSV-exposed sows. PRRSV outbreak phase was defined based on previously described methodologies after the detection of typical clinical signs of PRRSV infection. 541 Landrace sows had S/P ratio measured at ~54 days after the beginning of the PRRSV outbreak (S/Poutbreak), and 906 Landrace x Large White naïve F1 gilts had S/P ratio measured at ~50 days after vaccination with a commercial modified live PRRSV vaccine (S/PVx). 711 and 428 Landrace sows had reproductive performance recorded before and during the PRRSV outbreak, respectively. 811 vaccinated F1 animals had farrowing performance for up to 3 parities. All animals were genotyped for ~28K SNPs. The estimate of rg of S/Poutbreakwith S/PVx was high (rg±SE = 0.72±0.18). Estimates of rg of S/Poutbreak with reproductive performance in F1 sows were low to moderate, ranging from 0.05±0.23 (number stillborn) to 0.30±0.20 (total number born). Estimates of rg of S/PVxwith reproductive performance in non-infected purebred sows were moderate and favorable with number born alive (0.50±0.23), but low (0 to -0.11±0.23) with litter mortality traits. Estimates of rg of S/PVx were moderate and negative (-0.47±0.18) with the number of mummies in PRRSV-infected purebred sows and low with other traits (-0.29±0.18 for total number born to 0.05±0.18 for number stillborn). These results indicate that selection for antibody response following a PRRSV outbreak collected in purebred sows and to PRRSV vaccination collected in commercial crossbred gilts may increase litter size of non-infected and PRRSV-exposed purebred and commercial crossbred sows.

Selection for components of efficient lean growth rate in pigs 2. Selection pressure applied and direct responses in a Landrace herd

1994 ◽  
Vol 59 (2) ◽  
pp. 263-269 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Genetic Correlations ◽  
Correlated Response ◽  
Selection Line ◽  
Control Line ◽  
Direct Response ◽  
Lean Growth ◽  
Ad Libitum ◽  
Selection For ◽  
Ad Libitum Feeding

AbstractResponses to divergent selection for lean growth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Landrace pigs were studied. Selection was practised for four generations with a generation interval ofl year. A total of 2642 pigs were performance tested in the high, low and control lines, with an average of 37 boars and 39 gilts performance tested per selection line in each generation. The average within-line inbreeding coefficient at generation four was equal to 0·04. There was one control line for the DFI and LFC selection groups and another control line for the LGA selection group. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively with ad-libitum feeding. The selection criteria had phenotypic s.d. of 32, 29 and 274 units, for LGA, LFC and DFI, respectively, and results are presented in phenotypic s.d.Cumulative selection differentials (CSD) were 5·1, 4·5 and 5·5 phenotypic s.d. for LGA, LFC and DFI, respectively. Direct responses to selection were 1·4,1·1 and 0·9 (s.e. 0·20) for LGA, LFC and DFI. In each of the three selection groups, the CSD and direct responses to selection were symmetric about the control lines. The correlated response in LFC (1·1, s.e. 0·19) with selection on LGA was equal to the direct response in LFC. In contrast, the direct response in LGA was greater than the correlated response (0·7, s.e. 0·18) with selection on LFC. There was a negative correlated response in DFI (-0·6, s.e. 0·18) with selection on LFC, but the response with selection on LGA was not significant (0·2, s.e. 0·16).Heritabilities for LGA, LFC and DFI ivere 0·25, 0·25 and 0·18 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·12 (s.e. 0·02). Genetic correlations for LFC with LGA and DFI were respectively positive (0·87, s.e. 0·02) and negative (-0·36, s.e. 0·09), while the genetic correlation between DFI and LGA was not statistically different from zero, 0·13 (s.e. 0·10). Selection on components of efficient lean growth has identified LGA as an effective selection objective for improving both LGA and LFC, without a reduction in DFI.

Genetic variation in fatty acid composition of subcutaneous fat in cattle

2013 ◽  
Vol 53 (2) ◽  
pp. 129 ◽  
Author(s):  
M. J. Kelly ◽  
R. K. Tume ◽  
S. Newman ◽  
J. M. Thompson
Keyword(s):  
Fatty Acids ◽  
Genetic Variation ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Genetic Correlations ◽  
Subcutaneous Fat ◽  
Monounsaturated Fatty Acids ◽  
Selection For

Genetic parameters were estimated for fatty acid composition of subcutaneous beef fat of 1573 animals which were the progeny of 157 sires across seven breeds grown out on pasture and then finished on either grain or grass in northern New South Wales or in central Queensland. There was genetic variation in individual fatty acids with estimates of heritability for the proportions of C14 : 0, C14 : 1c9, C16 : 0, C16 : 1c9, C18 : 0 and C18 : 1c9 fatty acids in subcutaneous beef fat of the order of 0.4 or above. Also substantial correlations between some fatty acids were observed. Genetic correlations between fatty acids and fat depth at the P8 site suggested that much of the genetic variation in fatty acid composition was related to changes in fatness. Selection for decreased fatness resulted in decreased proportions of C18 : 1c9 with concomitant increases in C18 : 0, C14 : 0 and C16 : 0. This suggested that selection for decreased fatness at a given weight will result in a decrease in the proportions of monounsaturated fatty acids in the subcutaneous fat in the carcass with a corresponding increase in the proportions of saturated fatty acids.

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