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Vitezica Z.G.,National Polytechnic Institute of Toulouse | Vitezica Z.G.,French National Institute for Agricultural Research | Varona L.,University of Zaragoza | Varona L.,Instituto Agroalimentario Of Aragon Ia2 | And 4 more authors.
Genetics Selection Evolution | Year: 2016

Background: Most developments in quantitative genetics theory focus on the study of intra-breed/line concepts. With the availability of massive genomic information, it becomes necessary to revisit the theory for crossbred populations. We propose methods to construct genomic covariances with additive and non-additive (dominance) inheritance in the case of pure lines and crossbred populations. Results: We describe substitution effects and dominant deviations across two pure parental populations and the crossbred population. Gene effects are assumed to be independent of the origin of alleles and allelic frequencies can differ between parental populations. Based on these assumptions, the theoretical variance components (additive and dominant) are obtained as a function of marker effects and allelic frequencies. The additive genetic variance in the crossbred population includes the biological additive and dominant effects of a gene and a covariance term. Dominance variance in the crossbred population is proportional to the product of the heterozygosity coefficients of both parental populations. A genomic BLUP (best linear unbiased prediction) equivalent model is presented. We illustrate this approach by using pig data (two pure lines and their cross, including 8265 phenotyped and genotyped sows). For the total number of piglets born, the dominance variance in the crossbred population represented about 13 % of the total genetic variance. Dominance variation is only marginally important for litter size in the crossbred population. Conclusions: We present a coherent marker-based model that includes purebred and crossbred data and additive and dominant actions. Using this model, it is possible to estimate breeding values, dominant deviations and variance components in a dataset that comprises data on purebred and crossbred individuals. These methods can be exploited to plan assortative mating in pig, maize or other species, in order to generate superior crossbred individuals in terms of performance. © 2016 Vitezica et al.


PubMed | National Polytechnic Institute of Toulouse, University of Zaragoza, PIC North America, French National Institute for Agricultural Research and University of Georgia
Type: | Journal: Genetics, selection, evolution : GSE | Year: 2016

Most developments in quantitative genetics theory focus on the study of intra-breed/line concepts. With the availability of massive genomic information, it becomes necessary to revisit the theory for crossbred populations. We propose methods to construct genomic covariances with additive and non-additive (dominance) inheritance in the case of pure lines and crossbred populations.We describe substitution effects and dominant deviations across two pure parental populations and the crossbred population. Gene effects are assumed to be independent of the origin of alleles and allelic frequencies can differ between parental populations. Based on these assumptions, the theoretical variance components (additive and dominant) are obtained as a function of marker effects and allelic frequencies. The additive genetic variance in the crossbred population includes the biological additive and dominant effects of a gene and a covariance term. Dominance variance in the crossbred population is proportional to the product of the heterozygosity coefficients of both parental populations. A genomic BLUP (best linear unbiased prediction) equivalent model is presented. We illustrate this approach by using pig data (two pure lines and their cross, including 8265 phenotyped and genotyped sows). For the total number of piglets born, the dominance variance in the crossbred population represented about 13 % of the total genetic variance. Dominance variation is only marginally important for litter size in the crossbred population.We present a coherent marker-based model that includes purebred and crossbred data and additive and dominant actions. Using this model, it is possible to estimate breeding values, dominant deviations and variance components in a dataset that comprises data on purebred and crossbred individuals. These methods can be exploited to plan assortative mating in pig, maize or other species, in order to generate superior crossbred individuals in terms of performance.


Edwards L.N.,Colorado State University | Edwards L.N.,Kansas State University | Grandin T.,Colorado State University | Engle T.E.,Colorado State University | And 4 more authors.
Meat Science | Year: 2010

Two experiments (Exp.1, n = 80; Exp.2, n = 144) were conducted to determine the effects of pre-slaughter pig management on pork quality by monitoring blood lactate concentration ([LAC]) during marketing. [LAC] was measured at: (1) baseline at farm, (2) post-loading on truck, (3) pre-unloading after transport, (4) post-unloading at plant, (5) post-lairage, (6) post-movement to stun, and (7) exsanguination. Pearson correlations were used to determine relationships between [LAC] and meat quality. Higher [LAC] post-loading or a greater change in [LAC] during loading resulted in increased 24. h pH (P = 0.002, P = 0.0006, Exp.1; P = 0.0001, P = 0.01, Exp.2, respectively), decreased L* (P = 0.03, P = 0.04; P = 0.001, P = 0.01) and decreased drip loss (P= 0.02, P = 0.12; P = 0.002, P = 0.01). Even though improved handling during loading is important to animal well-being, it will not necessarily translate into improved pork quality. © 2010 The American Meat Science Association.


Edwards L.N.,Colorado State University | Grandin T.,Colorado State University | Engle T.E.,Colorado State University | Porter S.P.,Colorado State University | And 3 more authors.
Meat Science | Year: 2010

The objective of these studies (Exp.1, n=76; Exp.2, n=140) was to characterize the relationship of pre-slaughter animal-handling events to exsanguination blood lactate concentration ([LAC]) in a commercial pork processing plant. Pearson correlations indicated relationships (P<0.05) between [LAC] and the number of times a pig jammed, backed up and reared (Exp.1), and [LAC] was correlated (P<0.05) with electric prod use and vocalization in response to prod use in the crowd pen, as well as jamming in the single-file chute (Exp. 2). Single degree of freedom contrasts indicated that pigs experiencing one or more events (i.e., jamming, rearing and/or backing up) while moving through a single-file chute had greater (P<0.03) [LAC] than pigs that did not experience these events in both experiments, whereas pigs prodded in the crowd pen had greater (P=0.03) [LAC] than pigs that were not prodded (Exp. 2). This study provides data demonstrating that specific pre-slaughter animal-handling events are related to post-slaughter [LAC] in a commercial setting. © 2010.


Ibanez-Escriche N.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Forni S.,PIC North America | Noguera J.L.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Varona L.,University of Zaragoza
Livestock Science | Year: 2014

The inclusion of genomic information on prediction of breeding values has been explored by the pig breeding industry as molecular techniques evolved. Except for a few successful cases, for example the HAL-1843®, the use of genomic information for pig breeding has been limited. The development of SNP chips with high density markers across the genome coupled with new statistical methods allowed genomic selection (GS) to become a common practice. GS application entailed important advantages for pig breeding as it increased the accuracy of the breeding values for selection candidates and offered an opportunity for the practice of new selection strategies. Nevertheless, the application of GS is not straightforward for every target trait and breeding scheme. Many efforts have been done to evaluate the new methods and strategies to efficiently implement GS in pig breeding. Several aspects of the population and breeding objectives must be considered before GS is applied. This paper reviews the current status and challenges faced by pig breeders in the implementation of GS and the future opportunities that may arise as molecular technologies advance. © 2014 Elsevier B.V.


Kittawornrat A.,Iowa State University | Prickett J.,Iowa State University | Chittick W.,Iowa State University | Wang C.,Iowa State University | And 8 more authors.
Virus Research | Year: 2010

The purpose of this study was to determine whether oral fluid samples could be used to monitor individually-housed adult boars for porcine reproductive and respiratory syndrome virus (PRRSV) infection. In 3 trials, 24 boars were intramuscularly (IM) inoculated with a modified-live PRRSV (MLV) vaccine (Trial 1), a Type 1 PRRSV isolate (Trial 2), or a Type 2 isolate (Trial 3). Oral fluid samples were collected daily and serum samples were collected twice weekly. Following the completion of the study, samples were randomized and blind-tested for PRRSV by real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR). PRRSV was detected in oral fluids at DPI 1 and all oral fluid specimens were PRRSV qRT-PCR positive at DPI 4. Although PRRSV was detected in both serum and oral fluid specimens through DPI 21, a comparison of matched samples from individual boars showed that oral fluid was equal to serum for the detection of PRRSV at DPI 7 and more likely to be positive than serum on DPI 14 and 21. Overall, oral fluid was superior to serum for the detection of PRRSV using PCR over the 21-day observation period in this study. The results of this experiment suggest that individually-penned oral fluid sampling could be an efficient, cost-effective approach to PRRSV surveillance in boar studs and other swine populations. © 2010 Elsevier B.V.


Kittawornrat A.,Iowa State University | Engle M.,PIC North America | Panyasing Y.,Iowa State University | Olsen C.,Iowa State University | And 5 more authors.
BMC Veterinary Research | Year: 2013

Background: The object of this study was to describe and contrast the kinetics of the humoral response in serum and oral fluid specimens during acute porcine reproductive and respiratory syndrome virus (PRRSV) infection. The study involved three trials of 24 boars each. Boars were intramuscularly inoculated with a commercial modified live virus (MLV) vaccine (Trial 1), a Type 1 PRRSV field isolated (Trial 2), or a Type 2 PRRSV field isolate (Trial 3). Oral fluid samples were collected from individual boars on day post inoculation (DPI) -7 and 0 to 21. Serum samples were collected from all boars on DPI -7, 0, 7, 14, 21 and from 4 randomly selected boars on DPI 3, 5, 10, and 17. Thereafter, serum and oral fluid were assayed for PRRSV antibody using antibody isotype-specific ELISAs (IgM, IgA, IgG) adapted to serum or oral fluid.Results: Statistically significant differences in viral replication and antibody responses were observed among the three trials in both serum and oral fluid specimens. PRRSV serum IgM, IgA, and IgG were first detected in samples collected on DPI 7, 10, and 10, respectively. Oral fluid IgM, IgA, and IgG were detected in samples collected between DPI 3 to 10, 7 to 10, and 8 to 14, respectively.Conclusions: This study enhanced our knowledge of the PRRSV humoral immune response and provided a broader foundation for the development and application of oral fluid antibody-based diagnostics. © 2013 Kittawornrat et al.; licensee BioMed Central Ltd.


Patterson J.L.,University of Alberta | Cameron A.C.,University of Alberta | Smith T.A.,University of Alberta | Kummer A.B.,University of Alberta | And 4 more authors.
Journal of Swine Health and Production | Year: 2010

In sows treated at weaning with gonadotropins, weaning-to-estrus interval was shorter than in untreated controls, but the proportions of sows bred within a 3-day period or 7 days after weaning, farrowing rate, total born, and born alive did not differ with treatment.


Wilkinson J.M.,University of Cambridge | Wilkinson J.M.,University of Alberta | Sargent C.A.,University of Cambridge | Galina-Pantoja L.,PIC North America | And 2 more authors.
BMC Genomics | Year: 2010

Background: Haemophilus parasuis is the causative agent of Glässer's disease in pigs. Currently, little is known about the molecular mechanisms that contribute to disease susceptibility. This study used a porcine oligonucleotide microarray to identify genes that were differentially expressed (DE) in the lungs of colostrum-deprived animals previously characterized as being either 'Fully Resistant' (FR) or 'Susceptible' to infection by H. parasuis in a bacterial challenge experiment.Results: Gene expression profiles of 'FR' and 'Susceptible' animals were obtained by the identification of genes that were differentially expressed between each of these groups and mock-inoculated 'Control' animals. At 24 hours post-inoculation, a total of 21 and 58 DE genes were identified in 'FR' and 'Susceptible' animals respectively. At 72 hours, the numbers of genes were 20 and 347 respectively. 'FR' animals at 24 hours exhibited an increased expression of genes encoding extracellular matrix and TGF-β signalling components, possibly indicative of tissue repair following the successful early resolution of infection. The gene expression profile of 'FR' animals at 72 hours supported the hypothesis that higher levels of antibacterial activity were responsible for the 'FR' phenotype, possibly due to an increase in natural immunoglobulin A and decrease in signalling by the immunoregulatory transcription factor peroxisome proliferator-activated receptor gamma (PPAR-γ). The expression profile of 'Susceptible' animals at both time-points was characterized by an imbalance in signalling between pro and anti-inflammatory cytokines and an increased expression of genes involved in biological processes associated with inflammation. These include the pro-inflammatory cytokine genes resistin (RETN) and interleukin 1-beta (IL1B). At 72 hours, a reduction in the expression of genes involved in antigen presentation by both MHC class I and II molecules was observed, which could have contributed to the inability of 'Susceptible' animals to clear infection.Conclusions: This study is the first to have identified discrete sets of DE genes in pigs of differing susceptibility to H. parasuis infection. Consequently, several candidate genes and pathways for disease resistance or susceptibility phenotypes have been identified. In addition, the findings have shed light on the molecular pathology associated with Glässer's disease. © 2010 Wilkinson et al; licensee BioMed Central Ltd.


Lawlor M.R.,Purdue University | Craig B.A.,Purdue University | Schinckel A.P.,Purdue University | Einstein M.E.,Purdue University | And 10 more authors.
Professional Animal Scientist | Year: 2013

Barrows (n = 2,178) and gilts (n = 2,274) were fed either high-energy or low-energy diets from 27 kg of BW to target BW of 118, 127, 131.5, and 140.6 kg over 12 monthly replicates. Carcass primal cut and subprimal cut weights as well as optical probe backfat and loin depth measurements were collected on each pig. The cut weights and carcass measurements for each pig were fitted to allometric functions (Y = A . CWB) of carcass weight (CW), where A is a scalar parameter and B is the allometric coefficient. The final models were weight or measurement = random effect of replicate + (1+bDD).(A.CWB) + error, where bD is the regression coefficient, D (diet) = -0.5 for the low-energy and 0.5 for high-energy diets, and A and B are sire line-sex specific parameters. Linear regressions of backfat and loin depth residuals from the model were included at P <0.05 to the cut weight equations but had little effect to reduce the residual variance. The residuals among the primal and subprimal cuts were correlated, and a Cholesky decomposition procedure was used on the variance-covariance matrix of the residuals. By using these procedures, a stochastic model can be used to evaluate the effect of alternative management, marketing, and carcass sorting strategies on the mean and distribution of pork primal and subprimal cut weights to increase pork processor profitability. © 2013 American Registry of Professional Animal Scientists.

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