EFFECT OF SELECTION FOR CARCASS SCORE ON THE GENETIC IMPROVEMENT OF ITS COMPONENTS IN SWINE

1970 ◽  
Vol 50 (3) ◽  
pp. 585-592 ◽  
Author(s):  
M. H. FAHMY ◽  
C. BERNARD
Keyword(s):  
Analysis Of Variance ◽  
Genetic Improvement ◽  
Genetic Correlations ◽  
Feed Utilization ◽  
Backfat Thickness ◽  
Yorkshire Pigs ◽  
Selection For ◽  
Heritability Estimates ◽  
Sole Criterion ◽  
Three Components

Selection for carcass score was practiced for ten generations in two separate lines of Yorkshire pigs. Three components of the score were studied: carcass length, loin eye area, and backfat thickness. In line 2, carcass score was the sole criterion of selection, while in line 3, it was combined with feed utilization into an overall merit. Line 1, selected solely for feed utilization, served as a control. Carcass length and loin eye area increased by approximately 2 and 9%, respectively, in both lines. However, backfat thickness also increased by about 3% in line 2 and 0.4% in line 3. Pooled heritability estimates derived from the analysis of variance and the regression of offspring on mid-parent were 0.64 for carcass length, 0.48 for loin eye area and 0.67 for backfat thickness. Genetic correlations among the components of carcass score, between the components and carcass score and between the components and feed utilization were moderately high and favorable for combined genetic improvement of all traits.

EFFECT OF SELECTION ON FEED UTILIZATION AND CARCASS SCORE EN SWINE

1970 ◽  
Vol 50 (3) ◽  
pp. 575-584 ◽  
Author(s):  
C. BERNARD ◽  
M. H. FAHMY
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Genetic Improvement ◽  
Body Weight Gain ◽  
Feed Utilization ◽  
Phenotypic Correlation ◽  
Population Selection ◽  
Yorkshire Pigs ◽  
Selection For ◽  
Selection Differentials

Selection for feed utilization (FU) and carcass score (CS) based on full sib performance was practiced within three lines of Yorkshire pigs during ten generations. Line 1 was selected solely for FU, line 2 for CS and line 3 for the two traits combined in an index. Line 2 served as a control for lines 1 and 3 in FU and line 1 as a control for lines 2 and 3 in CS. Feed utilization was expressed as the amount of feed required per kilogram body weight gain. Carcass score was based on length, backfat thickness, loin eye area and belly grade measured on pigs marketed at 90 kg liveweight. Selection differentials for FU averaged 0.198 and 0.208 kg per generation for lines 1 and 3, respectively, while CS differentials were 7.2 and 7.4 points per generation for lines 2 and 3, respectively. Heritability estimates based on full sib performance and converted to individual bases were 0.16 for FU and 0.43 for CS. The phenotypic correlation between the two traits was −0.25 and the genetic correlation −0.55. Responses to selection for FU were 0.09 and 0.24 kg per generation for lines 1 and 3, respectively, while for CS they were 0.77 and 0.97 points for lines 2 and 3, respectively. Compared with the parental means, this represented a genetic improvement of 0.25 and 0.66% per generation for FU in lines 1 and 3, and 1.06 and 1.33% per generation for CS in lines 2 and 3, respectively. The realized responses in lines 1 and 3 to selection for FU Were 58 and 148% of the expectation, and 58 and 72% for lines 2 and 3 in CS. Due to larger selection differentials in line 3, along with a strong positive genetic correlation between the two traits observed in this particular population, selection for the combined traits was 1.35 and 1.10% more effective in improving FU and CS, respectively, than selection for these traits individually.

Estimates of genetic parameters for ultrasound-measured carcass traits in sheep

2004 ◽  
Vol 84 (3) ◽  
pp. 361-365 ◽  
Author(s):  
T. L. Fernandes ◽  
J. W. Wilton ◽  
J. J. Tosh
Keyword(s):  
Genetic Improvement ◽  
Variance Component ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Genetic Effect ◽  
Backfat Thickness ◽  
Additive Genetic Effect ◽  
Multiple Trait ◽  
Breed Group ◽  
Variance Component Estimates

Data on ultrasound traits (loin depth, average backfat thickness, and loin width) were collected from lambs (n = 3483) across Ontario, born between 1997 and 1999. The data were analysed with a REML procedure in a multiple-trait mixed-animal model to obtain (co)variance component estimates. Analyses of all traits included the additive genetic effect of the lamb, sex of the lamb, contemporary group, and breed group effects. Weight or age was included as a covariate in two separate analyses. Estimates of direct additive heritabilities for loin depth, average backfat thickness, and loin width were 0.29, 0.29 and 0.26 respectively, with genetic correlations of -0.17 between loin depth and average backfat thickness, 0.43 between loin depth and loin width, and 0.23 between loin width and average backfat thickness for the weight constant analysis. When the data were analysed using age in the regression analysis, corresponding estimates of direct additive heritabilities were 0.38, 0.35 and 0.30, and genetic correlations between traits were all positive, 0.29 between loin depth and average backfat thickness, 0.61 between loin depth and loin width, and 0.44 between loin width and average backfat thickness. Results indicate that it is possible to make genetic improvement if selection is based on ultrasound information. Key words: Sheep, genetic parameters, heritability, ultrasound

scholarly journals Host Genetics of Response to Porcine Reproductive and Respiratory Syndrome in Sows: Reproductive Performance

2021 ◽  
Vol 12 ◽  
Author(s):  
Felipe M. W. Hickmann ◽  
José Braccini Neto ◽  
Luke M. Kramer ◽  
Yijian Huang ◽  
Kent A. Gray ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
The Other ◽  
Nucleotide Polymorphisms ◽  
Host Genetics ◽  
Other Hand ◽  
Selection For ◽  
Heritability Estimates

Porcine Reproductive and Respiratory Syndrome (PRRS) is historically the most economically important swine disease worldwide that severely affects the reproductive performance of sows. However, little is still known about the genetic basis of reproductive performance in purebred herds during a PRRS outbreak through the comparison of maternal and terminal breeds. Thus, the objective of this work was to explore the host genetics of response to PRRS in purebred sows from two breeds. Reproductive data included 2546 Duroc and 2522 Landrace litters from 894 and 813 purebred sows, respectively, which had high-density genotype data available (29,799 single nucleotide polymorphisms; SNPs). The data were split into pre-PRRS, PRRS, and post-PRRS phases based on standardized farrow-year-week estimates. Heritability estimates for reproductive traits were low to moderate (≤0.20) for Duroc and Landrace across PRRS phases. On the other hand, genetic correlations of reproductive traits between PRRS phases were overall moderate to high for both breeds. Several associations between MARC0034894, a candidate SNP for response to PRRS, with reproductive performance were identified (P-value < 0.05). Genomic analyses detected few QTL for reproductive performance across all phases, most explaining a small percentage of the additive genetic variance (≤8.2%, averaging 2.1%), indicating that these traits are highly polygenic. None of the identified QTL within a breed and trait overlapped between PRRS phases. Overall, our results indicate that Duroc sows are phenotypically more resilient to PRRS than Landrace sows, with a similar return to PRRS-free performance between breeds for most reproductive traits. Genomic prediction results indicate that genomic selection for improved reproductive performance under a PRRS outbreak is possible, especially in Landrace sows, by training markers using data from PRRS-challenged sows. On the other hand, the high genetic correlations with reproductive traits between PRRS phases suggest that selection for improved reproductive performance in a clean environment could improve performance during PRRS, but with limited efficiency due to their low heritability estimates. Thus, we hypothesize that an indicator trait that could be indirectly selected to increase the response to selection for these traits would be desirable and would also improve the reproductive performance of sows during a PRRS outbreak.

Genetic parameters of the duration of fertility in hens

1992 ◽  
Vol 72 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Catherine Beaumont
Keyword(s):  
Maximum Likelihood ◽  
Key Words ◽  
Genetic Parameters ◽  
Control Period ◽  
Genetic Correlations ◽  
The Other ◽  
Selection For ◽  
Heritability Estimates ◽  
Highly Correlated ◽  
Box Cox Transformation

After two successive artificial inseminations (AI) with 125 × 106 spermatozoa, various characteristics of the duration of fertility were observed in 2375 egg-type hens at 33 and 44 wk of age: number of fertile (F) or hatched (H) eggs during a 21-d control period after AI, early, medium or late embryonic mortalities occurring at the same time and efficient (De) and maximum (Dm) duration (i.e. time between AI and the first clear egg or the last fertile egg, respectively). Heritability estimates of F, H, De or Dm ranged from 0.08 to 0.31. All genetic correlations between these variables (measured at the same age) were high (0.45–0.99) as well as those between the same variable measured at different ages (0.30–0.97). Estimates of genetic parameters varied little when estimated by Henderson's method III or REML but with the second method only all estimates were within the parameter space. A Box-Cox transformation of data slightly modified heritability estimates and animal ranking after genetic evaluation. The best criterion of selection for duration of fertility seems to be H as it is economically important, well heritable and highly correlated with the other characteristics of duration of fertility. Key words: Genetic parameters, fertility, poultry, Restricted Maximum Likelihood

A genetic analysis of wool characteristics and lamb performance traits in Scottish Blackface sheep

2003 ◽  
Vol 77 (3) ◽  
pp. 355-362 ◽  
Author(s):  
J. Conington ◽  
A. Murphy
Keyword(s):  
Genetic Correlations ◽  
Live Weight ◽  
Scoring Systems ◽  
Production Traits ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates ◽  
Wool Quality ◽  
Fleece Weight ◽  
The Uk

AbstractGenetic parameters were estimated for wool quality, fleece characteristics and lamb production traits for Scottish Blackface sheep reared under extensive hill conditions in the UK. In two separate studies, heritabilities and genetic correlations were estimated for wool quality traits measured on lambs at 5 months of age and again on the shorn fleece a year later. The wool traits included birth coat length (BCT), 10-point scores for proportion of grey and kemp fibres present in the fleece (grey, kemp), British Wool Marketing Board (BWMB) recommendation (REC), greasy fleece weight (FLWT), BWMB fleece grade (FLGR), and average staple length (ASL). Genetic and phenotypic correlations were estimated between lamb wool traits and lamb live weights at birth (BWT), marking (at mid lactation with an average age of 7 weeks) (MWT), weaning (at an average age of 17 weeks) (WWT) and slaughter (SLWT), average fat depth (AVFD) and average muscle depth (MD). Individual lamb carcass measurements included Meat and Livestock Commission (MLC) conformation score (CONF) and fat class (FATC). Heritability estimates measured on 2524 or more live lambs were 0·69, 0·52, 0·26, 0·42 and 0·31 for BCT, ASL, grey, kemp and REC respectively. Heritability estimates for traits measured on the shorn fleece a year later for 1415 ewes were 0·37, 0·02, 0·57, 0·43, 0·46 and 0·14 for ASL, grey, kemp, REC, FLWT and FLGR respectively. Genetic correlations between FLWT in hoggets and other wool were positive and moderate to high in magnitude, ranging from 0·22 for kemp in lambs to 0·48 for grey in hoggets. Genetic correlations between REC and live-weight traits were 0·39 for MWT, 0·37 for WWT and 0·44 for SLWT. Genetic correlation between ASL and ultrasonic fat depth was 0·15 and for ASL and ultrasonic muscle depth was -0·30. The results indicate that the simple scoring systems derived to assess these traits are useful indicators of fleece quality, are highly repeatable over time and are a good gauge of likely future wool production. The results indicate that selection for heavier, leaner lambs should not compromise fleece quality, as assessed in this study.

Genetic improvement of resistance to cyclaneusma needle cast in Pinus radiata

2019 ◽  
Vol 49 (2) ◽  
pp. 128-133 ◽  
Author(s):  
Mari Suontama ◽  
Yongjun Li ◽  
Charlie B. Low ◽  
Heidi S. Dungey
Keyword(s):  
New Zealand ◽  
Pinus Radiata ◽  
Genetic Improvement ◽  
Genetic Correlations ◽  
Tree Height ◽  
Progeny Testing ◽  
Environment Interaction ◽  
Needle Cast ◽  
Genotype Environment Interaction ◽  
Selection For

Progeny testing of resistance to needle loss caused by Cyclaneusma minus (cyclaneusma needle cast) has been included in the needle disease resistance strategy of Pinus radiata D. Don in New Zealand since the late 1970s. Data on progeny trials, two in the North Island of New Zealand and one in Tasmania, Australia, were available to estimate heritability between trait genetic correlations and genotype × environment interaction. Resistance to cyclaneusma needle cast had moderate estimates of heritability (0.25 to 0.46) at all sites. Genetic correlations between the assessed traits indicated that selection for faster early growth, i.e., tree height at age 4 years and diameter at breast height at age 6 years, favours trees that are prone to Cyclaneusma infection, while a favourable genetic association between resistance to cyclaneusma needle cast and productivity was evident at a later assessment at age 9 years. No significant genotype × environment interaction was found for resistance to cyclaneusma needle cast; however, stability of genotypes across a wider range of environments and with a high genetic connectedness requires more research. Considerable genetic improvement can be achieved for resistance to cyclaneusma needle cast and indirect selection for the trait should be pursued by selecting for productivity and culling susceptible genotypes from breeding.

scholarly journals Estimation of Genetic Parameters and Correlation between Yearling Ultrasound Measurements and Carcass Traits in Hanwoo Cattle

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1425
Author(s):  
Masoumeh Naserkheil ◽  
Deuk-Hwan Lee ◽  
Hong-Sik Kong ◽  
Jiyeon Seong ◽  
Hossein Mehrban
Keyword(s):  
Genetic Correlation ◽  
Genetic Parameters ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Backfat Thickness ◽  
Marbling Score ◽  
Muscle Area ◽  
Eye Muscle ◽  
Ultrasound Measurements ◽  
Heritability Estimates

Genetic parameters have a significant role in designing a breeding program and are required to evaluate economically important traits. The objective of this study was to estimate heritability and genetic correlation between yearling ultrasound measurements, such as backfat thickness (UBFT), eye muscle area (UEMA), intramuscular fat content (UIMF), and carcass traits, such as backfat thickness (BFT), carcass weight (CW), eye muscle area (EMA), marbling score (MS) at approximately 24 months of age, as well as yearling weight (YW) in Hanwoo bulls (15,796) and steers (5682). The (co) variance components were estimated using a multi-trait animal model. Moderate to high heritability estimates were obtained and were 0.42, 0.50, 0.56, and 0.59 for CW, EMA, BFT, and MS, respectively. Heritability estimates for yearling measurements of YW, UEMA, UBFT, and UIMF were 0.31, 0.32, 0.30, and 0.19, respectively. Favorable and strong genetic correlations were observed between UIMF and MS (0.78), UBFT and BFT (0.63), and UEMA and EMA (0.65). Moreover, the estimated genetic correlation between YW and CW was high (0.84) and relatively moderate between YW and EMA (0.43). These results suggest that genetic improvement can be achieved for carcass traits when using yearling ultrasound measurements as selection criteria in ongoing Hanwoo breeding programs.

scholarly journals Fundamentskriterien als Selektionsmerkmale in Schweinezuchtprogrammen (Kurzmitteilung)

1999 ◽  
Vol 42 (6) ◽  
pp. 611-618
Author(s):  
J. Krieter ◽  
U. Presuhn
Keyword(s):  
Scoring System ◽  
Selection Pressure ◽  
Short Communication ◽  
Genetic Correlations ◽  
Backfat Thickness ◽  
Pure Breed ◽  
Performance Traits ◽  
Breeding Programmes ◽  
Selection For ◽  
Daily Gain

Abstract. Title of the paper: Linear scoring System of legs as selection tool in swine breeding programmes (short communication) A linear scoring system was used to describe leg traits of two pure breed lines of a swine breeding program. Seven Traits were defined on a scale of −3 to +3. Standard deviations, min- and max-values indicate a high variation of the traits. The estimated heritabilities ränge from h2 = 0.10 to 0.25. The genetic correlations between performance traits (live daily gain, backfat thickness) and exterior traits are antagonistic. Therefore further selection pressure for better Performance traits should take account selection for leg traits.

Heritability estimates of wool follicle traits in sheep skin

1984 ◽  
Vol 39 (3) ◽  
pp. 399-403 ◽  
Author(s):  
M. A. Abouheif ◽  
C. LeRoy Johnson ◽  
M. P. Botkin
Keyword(s):  
Effective Means ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Heritability Estimate ◽  
Histological Techniques ◽  
Sources Of Variation ◽  
Wool Follicle ◽  
Selection For ◽  
Heritability Estimates ◽  
Fleece Weight

ABSTRACTData were collected from 600 newborn lambs, offspring of 354 Western crossbred ewes and 26 rams, to determine heritability estimates as well as phenotypic and genetic correlations between wool follicle variables using histological techniques. Breed of sire and sire within breed were significant sources of variation in total and secondary wool follicle populations and secondary:primary (S:P) ratio. Heritability estimates calculated by regression of offspring on dam were slightly higher than by paternal half-sib correlation or regression of offspring on sire. Expressed as an average of the three methods of calculation, the heritability estimate for S:P ratio was highest (0·69), followed by estimates for secondary, total and primary wool follicles (0·52, 0·46 and 0·36, respectively). These estimates are similar to the heritabilities of fleece weight, staple length and fibre diameter. Selection for increased density, provided an accurate measure is used, is suggested as an effective means for increasing fleece weight within grade.

Heat stress effects on farrowing rate in sows: Genetic parameter estimation using within-line and crossbred models1

2012 ◽  
Vol 90 (7) ◽  
pp. 2109-2119 ◽  
Author(s):  
S. Bloemhof ◽  
A. Kause ◽  
E. F. Knol ◽  
J.A.M. Van Arendonk ◽  
I. Misztal
Keyword(s):  
Genetic Variation ◽  
Genetic Correlation ◽  
Heat Tolerance ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Random Regression ◽  
Production Traits ◽  
Selection For ◽  
Heritability Estimates ◽  
Farrowing Rate

Abstract The pork supply chain values steady and undisturbed piglet production. Fertilization and maintaining gestation in warm and hot climates is a challenge that can be potentially improved by selection. The objective of this study was to estimate 1) genetic variation for farrowing rate of sows in 2 dam lines and their reciprocal cross; 2) genetic variation for farrowing rate heat tolerance, which can be defined as the random regression slope of farrowing rate against increasing temperature at day of insemination, and the genetic correlation between farrowing rate and heat tolerance; 3) genetic correlation between farrowing rate in purebreds and crossbreds; and 4) genetic correlation between heat tolerance in purebreds and crossbreds. The estimates were based on 93,969 first insemination records per cycle from 24,456 sows inseminated between January 2003 and July 2008. These sows originated from a Dutch purebred Yorkshire dam line (D), an International purebred Large White dam line (ILW), and from their reciprocal crosses (RC) raised in Spain and Portugal. Within-line and crossbred models were used for variance component estimation. Heritability estimates for farrowing rate were 0.06, 0.07, and 0.02 using within-line models for D, ILW, and RC, respectively, and 0.07, 0.07, and 0.10 using the crossbred model, respectively. For farrowing rate, purebred-crossbred genetic correlations were 0.57 between D and RC and 0.50 between ILW and RC. When including heat tolerance in the within-line model, heritability estimates for farrowing rate were 0.05, 0.08, and 0.03 for D, ILW, and RC, respectively. Heritability for heat tolerance at 29.3°C was 0.04, 0.02, and 0.05 for D, ILW, and RC, respectively. Genetic correlations between farrowing rate and heat tolerance tended to be negative in crossbreds and ILW-line sows, implying selection for increased levels of production traits, such as growth and reproductive output, is likely to increase environmental sensitivity. This study shows that genetic selection for farrowing rate and heat tolerance is possible. However, when this selection is based solely on purebred information, the expected genetic progress on farrowing rate and heat tolerance in crossbreds (commercial animals) would be inconsequential.

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