PSVII-27 Genetic analysis of disease resilience of nursery-to-finish pigs under a natural disease challenge model using reaction norms

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 235-235
Author(s):  
Jian Cheng ◽  
KyuSang Lim ◽  
Austin Putz ◽  
Anna Wolc ◽  
John Harding ◽  
...  
Keyword(s):  
Genetic Model ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Reaction Norm ◽  
Cubic Spline ◽  
Clinical Disease ◽  
Random Regression ◽  
Disease Phenotypes ◽  
Linear Reaction ◽  
Better Than

Abstract Disease resilience is the ability of an animal to maintain performance across environments with different disease challenge loads (CL) and can be quantified using random regression reaction norm models that describe phenotype as a function of CL. Objectives of this study were to: 1) develop measures of CL using growth rate and clinical disease phenotypes under a natural disease challenge; 2) evaluate genetic variation in disease resilience. Data used were late nursery and finisher growth rates and clinical disease phenotypes, including medical treatment and mortality rates, and subjective health scores, collected on 50 batches of 60/75 crossbred (LRxY) barrows under a polymicrobial natural disease challenge. All pigs were genotyped using a 650K SNP panel. Different CL were derived from estimates of contemporary group effects and used as environmental covariates in reaction norm analyses of average daily gain (ADG) and treatment rate (TRT). The CL were compared based on model loglikelihoods and estimates of genetic variance, using both linear and cubic spline reaction norm models. Linear reaction norm models fitted the data significantly better than the standard genetic model and the cubic spline models fitted the data significantly better than the linear reaction norm model for most traits. CL based on early finisher ADG provided the best fit for nursery ADG, while CL based on clinical disease phenotypes was best for finisher ADG and TRT. With increasing CL, estimates of heritability for ADG initially decreased and then increased, while estimates of heritability for TRT generally increased with CL. Genetic correlations were low between ADG or TRT at high versus low CL but high for close CLs. Results can be used to select more resilient pigs across different CL levels, or high-performance animals at a given CL level, or a combination of these. Funded by Genome Canada, Genome Alberta, USDA-NIFA, and PigGenCanada.

scholarly journals Evaluation of the sensitivity of pulmonary arterial pressure to elevation using a reaction norm model in Angus Cattle

2020 ◽  
Vol 98 (5) ◽  
Author(s):  
Scott E Speidel ◽  
Milton G Thomas ◽  
Timothy N Holt ◽  
R Mark Enns
Keyword(s):  
Arterial Pressure ◽  
High Altitude ◽  
Genetic Relationship ◽  
Pulmonary Arterial Pressure ◽  
Genetic Correlations ◽  
Reaction Norm ◽  
High Elevation ◽  
Random Regression ◽  
Angus Cattle ◽  
Pulmonary Arterial

Abstract Pulmonary arterial pressure (PAP) is a diagnostic measure used to determine an individual’s susceptibility to developing high-altitude disease. The importance of PAP measures collected at elevations lower than the intended breeding elevation of the bulls (i.e., ≥1,520 m) is unknown. Therefore, the objective of this study was to determine the genetic relationship between PAP measures collected in a range of elevations using reaction norm models. A total of 9,177 PAP and elevation observations on purebred Angus cattle, which averaged 43.49 ± 11.32 mmHg and 1,878.6 ± 296.8 m, respectively, were used in the evaluation. The average age of the individuals in the evaluation was 434.04 ± 115.9 d. A random regression model containing the effects of sex, a linear covariate of age, a quadratic fixed covariate of elevation, and random effects consisting of a contemporary group and a linear regression of PAP on elevation was used for the evaluation of PAP. Two forms of PAP were evaluated with this model. First, to address the non-normality of the data, PAP was raised to the power of −2.6 (ptPAP) based on the results of a Box–Cox analysis. Second, raw PAP (rPAP) phenotypes were evaluated to compare the results to those obtained from the transformed data. For ptPAP, heritability ranged from 0.25 to 0.37 corresponding to elevations of 1,900 and 1,215 m, respectively. For rPAP, heritability ranged from 0.22 to 0.41 corresponding to elevations of 1,700 and 2,495 m, respectively. Generally, lower elevations corresponded to decreased heritabilities while higher elevations corresponded to increased heritability estimates. For ptPAP, genetic correlations ranged from 0.18 (elevation: 1,215 and 2,495 m) to 1.00. For rPAP, genetic correlations ranged from 0.08 (elevation: 1,215 and 2,495 m) to 1.00. In general, the closer the elevations in which PAP was measured, the greater the genetic relationship. The greater the difference in elevation between PAP measures resulted in lower genetic correlations. The rank correlation between expected progeny differences (EPD) for 1,215 and 2,495 m was 0.65 and 0.49 for the ptPAP and rPAP, respectively. These results suggested that PAP measures collected in lower elevations may be used as an indicator of high-altitude adaptability. In the estimation of EPD to rank sires for their suitability for use in high-elevation production systems, it is important to account for the relationships among varied altitudes.

scholarly journals When three traits make a line: Evolution of phenotypic plasticity and genetic assimilation through linear reaction norms in stochastic environments

2015 ◽  
Author(s):  
Torbjorn Ergon ◽  
Rolf Ergon
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Correlations ◽  
Reaction Norm ◽  
Genetic Effects ◽  
Environmental Perception ◽  
Genetic Assimilation ◽  
Reaction Norms ◽  
Environmental Value ◽  
Linear Reaction ◽  
Definition Of

Genetic assimilation results from selection on phenotypic plasticity, but quantitative genetics models of linear reaction norms considering intercept and slope as traits do not fully incorporate the process of genetic assimilation. We argue that intercept-slope reaction norm models are insufficient representations of genetic effects on linear reaction norms, and that considering reaction norm intercept as a trait is unfortunate because the definition of this trait relates to a specific environmental value (zero) and confounds genetic effects on reaction norm elevation with genetic effects on environmental perception. Instead we suggest a model with three traits representing genetic effects that respectively (i) are independent of the environment, (ii) alter the sensitivity of the phenotype to the environment, and (iii) determine how the organism perceives the environment. The model predicts that, given sufficient additive genetic variation in environmental perception, the environmental value at which reaction norms tend to cross will respond rapidly to selection after an abrupt environmental change, and eventually become equal to the new mean environment. This readjustment of the zone of canalization becomes completed without changes in genetic correlations, genetic drift or imposing any fitness costs on maintaining plasticity. The asymptotic evolutionary outcome of this three-trait linear reaction norm generally entails a lower degree of phenotypic plasticity than the two-trait model, and maximum expected fitness does not occur at the mean trait values in the population.

A comparison of the growth of Brahman and F1 Senepol × Brahman steers in an Indonesian feedlot

2017 ◽  
Vol 57 (10) ◽  
pp. 2096 ◽  
Author(s):  
T. J. Schatz
Keyword(s):  
Mortality Rate ◽  
Bos Taurus ◽  
Average Daily Gain ◽  
Northern Territory ◽  
Feeding Period ◽  
Crossbred Cattle ◽  
Brahman Steers ◽  
Daily Gain ◽  
Better Than ◽  
Live Export

This study compares the performance of F1 Senepol × Brahman steers (F1 SEN) to Brahman (BRAH) steers in an Indonesian feedlot. The focus was to address concerns that crossbred cattle are discriminated against by live export cattle buyers due to a perception that they do not perform as well as Brahmans in Indonesian feedlots. F1 SEN (n = 54) and BRAH (n = 32) steers that had grazed together since weaning at Douglas Daly Research Farm (Northern Territory) were exported to Indonesia and fed for 121 days in a feedlot near Lampung (Sumatra, Indonesia). The average daily gain of the F1 SEN steers over the feeding period was 0.17 kg/day higher (P < 0.001) than the BRAH steers (1.71 vs 1.54 kg/day). As a result the F1 SEN put on an average of 21.6 kg more over the 121-day feeding period and they did not have a higher mortality rate. Consequently, F1 SEN steers performed better than BRAH in an Indonesian feedlot and these results should encourage live export cattle buyers to purchase this type of cattle (Brahman crossed with a tropically adapted Bos taurus breed) with confidence that they can perform at least as well as Brahmans in Indonesian feedlots, although it should be noted that growth rates are usually higher in F1 crosses than in subsequent generations.

scholarly journals The coalescent process in models with selection, recombination and geographic subdivision

1991 ◽  
Vol 57 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Norman Kaplan ◽  
Richard R. Hudson ◽  
Masaru Iizuka
Keyword(s):  
Genetic Variation ◽  
Population Genetic ◽  
Genetic Model ◽  
Sequence Data ◽  
Balancing Selection ◽  
Similar Model ◽  
Proposed Model ◽  
Coalescent Approach ◽  
Neutral Mutations ◽  
Better Than

SummaryA population genetic model with a single locus at which balancing selection acts and many linked loci at which neutral mutations can occur is analysed using the coalescent approach. The model incorporates geographic subdivision with migration, as well as mutation, recombination, and genetic drift of neutral variation. It is found that geographic subdivision can affect genetic variation even with high rates of migration, providing that selection is strong enough to maintain different allele frequencies at the selected locus. Published sequence data from the alcohol dehydrogenase locus of Drosophila melanogaster are found to fit the proposed model slightly better than a similar model without subdivision.

An analysis of the variation in the lean tissue distribution of sheep

1982 ◽  
Vol 34 (3) ◽  
pp. 257-264 ◽  
Author(s):  
B. T. Wolf
Keyword(s):  
Tissue Distribution ◽  
Genetic Correlation ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Maximum Difference ◽  
Lean Tissue ◽  
Heritability Estimates ◽  
The Relationship ◽  
Daily Gain ◽  
Sire Breed

ABSTRACTThe distribution of lean tissue between eight standard joints was examined in 956 crossbred lambs slaughtered at constant live weights of either 35 or 40 kg. The sire breeds used were the Dorset Down, Ile-de-France, Oldenburg, Oxford, Suffolk and Texel. Sire breed did not have a significant effect on the proportion of total carcass lean found in the higher-priced joints but did show significant differences in the proportion of total carcass lean found in individual joints, with a maximum difference of 7·7 g total lean per kg joint being recorded. Similarly, small but significant effects due to ewe age (1 to 3 years), rearing type (single, twin, triplet), sex (male castrate, female) and weight of total lean were reported for the proportion of total carcass lean found in different joints.Heritability estimates ranged from 0·07 (s.e. 008) to 0·65 (s.e. 0·16) for the proportion of total lean in the best-end neck and higher-priced joints respectively. Phenotypic standard deviations of 5·8g/kg and 17·9g/kg were reported for the proportion of total lean found in the best-end neck and the higher-priced joints respectively. The genetic correlations between the proportion of total lean in each of the higher-priced joints and the proportion of total lean in the higher-priced joints combined were positive. A genetic correlation of 017 (s.e. 0·20) was found for the relationship between average daily gain from birth to slaughter and the proportion of total lean in the higher-priced joints.

HERITABILITIES AND GENETIC CORRELATIONS FOR ULTRASONIC BACKFAT MEASUREMENTS, GROWTH AND CARCASS TRAITS IN SWINE

1982 ◽  
Vol 62 (3) ◽  
pp. 665-670 ◽  
Author(s):  
D. C. JEFFRIES ◽  
R. G. PETERSON
Keyword(s):  
Key Words ◽  
Genetic Correlation ◽  
Genetic Parameters ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Ultrasonic Measurements ◽  
Yorkshire Pigs ◽  
Daily Gain ◽  
Season Interaction

Genetic parameters were estimated for 2403 purebred Yorkshire pigs over a 2-yr period, representing 21 sires. The traits studied included average daily gain, age adjusted to 90 kg, ultrasonic measurements of backfat at the mid-back and loin positions, total and adjusted total ultrasonic backfat and corresponding carcass backfat measurements. Least squares analyses were used to estimate and adjust for the effects of sex, year-season and sex by year-season interaction. Heritabilities and genetic correlations were calculated for all traits using both half- and full-sib estimates. Adjusted age and adjusted total ultrasonic backfat measurements were found to have the highest heritabilities of the live traits in this study. Estimates of heritability for adjusted age and adjusted total ultrasonic backfat were 0.24 ± 0.10 and 0.26 ± 0.10 based on half-sib and 0.56 ± 0.07 and 0.41 ± 0.06 from full-sib analyses. The genetic correlation between these two traits was −0.07 ± 0.28 based on the half-sib method. The total phenotypic correlation was −0.01 ± 0.02. Key words: Swine, ultrasonic backfat, heritabilities, genetic correlations

scholarly journals (Co)variance components and genetic parameters for growth rate and Kleiber ratio in fat-tailed Mehraban sheep

2013 ◽  
Vol 56 (1) ◽  
pp. 564-572 ◽  
Author(s):  
F. Ghafouri-Kesbi
Keyword(s):  
Growth Rate ◽  
Variance Components ◽  
Genetic Parameters ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Phenotypic Variance ◽  
Genetic Progress ◽  
Kleiber Ratio ◽  
Derivative Free ◽  
Maternal Heritability

Abstract. The aim of the present study was to estimate (co)variance components and genetic parameters for average daily gain from birth to weaning (ADGa), weaning to 6 months (ADGb), weaning to 9 months (ADGc), 6 months to 9 months (ADGd) and corresponding Kleiber ratios (KRa, KRb, KRc and KRd) in Mehraban sheep. A derivative-free algorithm combined with a series of six univariate linear animal models was used to estimate phenotypic variance and its direct, maternal and residual components. In addition, bivariate analyses were done to estimate (co)variance components between traits. Estimates of direct heritability (h2) were 0.10, 0.11, 0.16, 0.09, 0.13, 0.13, 0.15 and 0.08 for ADGa, ADGb, ADGc, ADGd, KRa, KRb, KRc and KRd, respectively and indicate that in Mehraban sheep genes contribute very little to the variance of the growth rate and Kleiber ratio. Estimates of maternal heritability (m2) were 0.10, 0.08 and 0.05 for ADGa, KRa and KRb, respectively. Direct additive genetic correlations ranged from −0.32 (KRa-KRd) to 0.99 (ADGb-KRb) and phenotypic correlations ranged from −0.53 (ADGa- ADGd) to 0.99 (ADGa-KRa). Estimates of direct heritability and genetic correlations show that genetic improvement in efficiency of feed utilization through selection programmes is possible, though it would generate a relatively slow genetic progress.

scholarly journals Estimation of genetic parameters and comparison of random regression animal and sire models of production traits in the first three lactations of Iranian Holsteins

2014 ◽  
Vol 30 (2) ◽  
pp. 261-279 ◽  
Author(s):  
A. Mohammadi ◽  
S. Alijani
Keyword(s):  
Milk Fat ◽  
Genetic Parameters ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Random Regression ◽  
Lactation Period ◽  
Production Traits ◽  
Environmental Variance ◽  
In The Beginning ◽  
Residual Variances

This study was conducted to compare of random regression (RR) animal and sire models for estimation of the genetic parameters for production traits of Iranian Holstein dairy cows. For this purpose, the test day records were used belonged to first three lactations of cows and for, milk, fat and protein yields traits where, collected from 2003 to 2010, by the national breeding center of Iran. The genetic parameters were estimated using restricted maximum likelihood algorithm. To compare the model, different criterion -2logL value, AIC, BIC and RV were used for considered traits. Residual variances were considered homogeneous over the lactation period. Obtained results showed that additive genetic variance was highest in the beginning and end lactation and permanent environmental variance was highest in beginning of lactation than other lactation period. Heritabilities estimate for milk, fat and protein yields by RR animal and sire models were found to be lowest during early lactation (0.05, 0.04 and 0.07; 0.05, 0.19 and 0.13; 0.14, 0.19 and 0.15, for milk, fat and protein yields and in first, second and third lactation respectively). However, estimated heritabilities during lactation did not vary among different order Legendre polynomials, and also between RR animal and sire models. The variation in genetic correlations estimate in the RR animal and sire models was larger in the first lactation than in the second and third lactations. Thus, based on the results obtained, it can be inferred that the RR animal model is better for modeling yield traits in Iranian Holsteins.

Genetic parameters for osteochondrosis traits in elbow joints of crossbred pigs and relationships with production traits

2005 ◽  
Vol 81 (3) ◽  
pp. 319-324 ◽  
Author(s):  
B. Jørgensen ◽  
B. Nielsen
Keyword(s):  
Genetic Model ◽  
Genetic Correlations ◽  
Joint Surface ◽  
Production Traits ◽  
Medial Condyle ◽  
Phenotypic Correlations ◽  
Left Elbow ◽  
Meat Content ◽  
Humeral Condyle ◽  
Crossbred Pigs

AbstractA total of 9360 offspring of 12 purebred Duroc sires and 692 Landrace × Yorkshire sows were evaluated for six osteochondrosis traits in the left elbow joints at slaughter. Osteochondrosis traits, growth pre- and post weaning, and meat content at slaughter were analysed simultaneously by a multivariate genetic model. Castrates scored worse than female pigs for nearly all osteochondral traits. Heritability of elbow osteochondrosis was moderate (0·02 to 0·28) and, thus, selection against the disorder is possible. Phenotypic correlations among joint surface abnormalities, cartilage thickness, subchondral lesions and cracks in the cartilage at the osteochondral junction in the medial condyle ranged from 0·33 to 0·69, whereas genetic correlations ranged from 0·75 to 0·97. Phenotypic correlations of the sagittal central groove with other abnormalities in the medial condyle were low and insignificant but genetic correlations were strongly significant (0·66 to 0·77). Depression of the proximal edge of the radius was to some extent phenotypically correlated to abnormalities in the medial humeral condyle (around 0·2), while genetic correlations ranged from 0·05 to 0·52. Significant genetic correlations among osteochondral traits indicate that all are part of the osteochondrosis complex. Abnormalities in the joint surface showed the strongest genetic correlations with other osteochondrosis variables in the elbow joint and were moderately inherited (h2 = 0·22), which indicates that this trait can be used as a marker to select against osteochondrosis. Osteochondral traits had no significant genetic correlations with growth to weaning and to 30 kg, slight negative (favourable) genetic correlations with growth from 30 to 100 kg, and slightly positive (unfavourable) genetic correlations with meat content in carcass.

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