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1.
J Dairy Sci ; 107(2): 992-1021, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37730179

RESUMO

Genetic and genomic analyses of longitudinal traits related to milk production efficiency are paramount for optimizing water buffaloes breeding schemes. Therefore, this study aimed to (1) compare single-trait random regression models under a single-step genomic BLUP setting based on alternative covariance functions (i.e., Wood, Wilmink, and Ali and Schaeffer) to describe milk (MY), fat (FY), protein (PY), and mozzarella (MZY) yields, fat-to-protein ratio (FPR), somatic cell score (SCS), lactation length (LL), and lactation persistency (LP) in Murrah dairy buffaloes (Bubalus bubalis); (2) combine the best functions for each trait under a multiple-trait framework; (3) estimate time-dependent SNP effects for all the studied longitudinal traits; and (4) identify the most likely candidate genes associated with the traits. A total of 323,140 test-day records from the first lactation of 4,588 Murrah buffaloes were made available for the study. The model included the average curve of the population nested within herd-year-season of calving, systematic effects of number of milkings per day, and age at first calving as linear and quadratic covariates, and additive genetic, permanent environment, and residual as random effects. The Wood model had the best goodness of fit based on the deviance information criterion and posterior model probabilities for all traits. Moderate heritabilities were estimated over time for most traits (0.30 ± 0.02 for MY; 0.26 ± 0.03 for FY; 0.45 ± 0.04 for PY; 0.28 ± 0.05 for MZY; 0.13 ± 0.02 for FPR; and 0.15 ± 0.03 for SCS). The heritability estimates for LP ranged from 0.38 ± 0.02 to 0.65 ± 0.03 depending on the trait definition used. Similarly, heritabilities estimated for LL ranged from 0.10 ± 0.01 to 0.14 ± 0.03. The genetic correlation estimates across days in milk (DIM) for all traits ranged from -0.06 (186-215 DIM for MY-SCS) to 0.78 (66-95 DIM for PY-MZY). The SNP effects calculated for the random regression model coefficients were used to estimate the SNP effects throughout the lactation curve (from 5 to 305 d). Numerous relevant genomic regions and candidate genes were identified for all traits, confirming their polygenic nature. The candidate genes identified contribute to a better understanding of the genetic background of milk-related traits in Murrah buffaloes and reinforce the value of incorporating genomic information in their breeding programs.


Assuntos
Búfalos , Leite , Feminino , Animais , Leite/metabolismo , Búfalos/genética , Búfalos/metabolismo , Estudo de Associação Genômica Ampla/veterinária , Melhoramento Vegetal , Lactação/genética , Fenótipo
2.
J Anim Breed Genet ; 140(2): 167-184, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36326492

RESUMO

There is a great worldwide demand for cheese made with buffalo milk, due to its flavour and nutritional properties. In this context, there is a need for increasing the efficiency of buffalo milk production (including lactation persistence), which can be achieved through genomic selection. The most used methods for the genetic evaluation of longitudinal data, such as milk-related traits, are based on random regression models (RRM). The choice of the best covariance functions and polynomial order for modelling the random effects is an important step to properly fit RRM. To our best knowledge, there are no studies evaluating the impact of the order and covariance function (Legendre polynomials-LEG and B-splines-BSP) used to fit RRM for genomic prediction of breeding values in dairy buffaloes. Therefore, the main objectives of this study were to estimate variance components and evaluate the performance of LEG and BSP functions of different orders on the predictive ability of genomic breeding values for the first three lactations of milk yield (MY1, MY2, and MY3) and lactation persistence (LP1, LP2, and LP3) of Brazilian Murrah. Twenty-two models for each lactation were contrasted based on goodness of fit, genetic parameter estimates, and predictive ability. Overall, the models of higher orders of LEG or BSP had a better performance based on the deviance information criterion (DIC). The daily heritability estimates ranged from 0.01 to 0.30 for MY1, 0.08 to 0.42 for MY2, and from 0.05 to 0.47 for MY3. For lactation persistence (LP), the heritability estimates ranged from 0.09 to 0.32 for LP1, from 0.15 to 0.33 for LP2, and from 0.06 to 0.32 for LP3. In general, the curves plotted for variance components and heritability estimates based on BSP models presented lower oscillation along the lactation trajectory. Similar predictive ability was observed among the models. Considering a balance between the complexity of the model, goodness of fit, and credibility of the results, RRM using quadratic B-splines functions based on four or five segments to model the systematic, additive genetic, and permanent environment curves provide better fit with no significant differences between genetic variances estimates, heritabilities, and predictive ability for the genomic evaluation of dairy buffaloes.


Assuntos
Búfalos , Leite , Feminino , Animais , Búfalos/genética , Análise de Regressão , Lactação/genética , Genômica
3.
J Appl Genet ; 63(2): 379-388, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35075583

RESUMO

The research article was carried out with the objective of studying the genetic variation on the resilience of buffaloes to negative energy balance-NEB (measured by changes in body weight in early lactation)-as well as investigating genomic regions of interest for this trait. A model of reaction norms was used, considering milk production as the trait to be analyzed and solutions of the contemporary groups to weight changes as environmental gradient. In this methodology, the genetic value of the slope represents the measure of resilience of the animals. After the estimation step, a genome-wide association analysis was performed for the slope of the reaction norms model, to obtain a list of windows and associated genes. The heritability estimates for milk production over the resilience gradient ranged from 0.13 to 0.28, with lower values in the intermediate environmental groups. Regarding the productive resilience of dairy buffalo cows to NEB, the genomic windows with the highest contribution to the genetic variance were detected on chromosomes BBU 1, 2, 3, 4, 9, 12, 19, and 21. A functional analysis of the genes described in the selected windows indicated association with metabolic routes related to growth and immunity of the animals, with an emphasis on the STAT6 gene. The results presented indicate that there is for this trait genetic variation to be used as selection criteria, in addition to genomic regions that can increase the precision of the selection.


Assuntos
Búfalos , Estudo de Associação Genômica Ampla , Animais , Búfalos/genética , Bovinos/genética , Feminino , Estudo de Associação Genômica Ampla/veterinária , Genômica , Lactação/genética , Leite
4.
J Anim Breed Genet ; 139(2): 215-230, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34841606

RESUMO

The objectives of this study were to assess the effects of heat stress on the milk yield and investigate the presence of genotype × environment interaction (G × E) in Brazilian Murrah buffaloes reared under tropical conditions. With this, 58,070 test-day (TD) records for milk yield from 3,459 first lactations of buffaloes collected between 1987 and 2018 were evaluated. A mixed model considering days in milk (DIM) and temperature-humidity index (THI) was applied to quantify milk yield losses due to heat stress. The most detrimental effect of THI on TD milk yield was observed in the mid-stages of lactation, after lactation peak, in DIM 105-154 and 155-204 days (-0.020 and -0.015 kg/day per THI, respectively). The least-squares means of TD milk yield were used to identify a heat stress threshold using a piecewise linear regression model. A substantial reduction in TD milk yield due to heat stress was observed for THI values above 77.8 (-0.251 kg/day per increase of 1 THI unit). An analysis using a single-trait random regression animal model was carried out to estimate variance components and genetic parameters for TD milk yield over THI and DIM values. Increased additive genetic variance and heritability estimates were observed for extreme THI values (THI = 60 and 80) combined with mid-lactation stages. The lowest genetic correlation (0.50) was observed between TD records at opposite extremes of the THI scale (THI = 60 vs. THI = 80). The genetic trends observed for the regression coefficients related to the general level of production (0.02) and specific ability to respond to heat stress (-0.002) indicated that selection to increase milk yield did not affect the specific ability to respond to heat stress until the present moment. These trends reflect the low genetic correlation between these components (0.05 ± 0.14). In this sense, monitoring trends of genetic components related to response to heat stress is recommended.


Assuntos
Transtornos de Estresse por Calor , Leite , Animais , Búfalos/genética , Feminino , Transtornos de Estresse por Calor/genética , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico/genética , Temperatura Alta , Lactação
5.
J Dairy Sci ; 104(5): 5768-5793, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33685677

RESUMO

Genomic selection has been widely implemented in many livestock breeding programs, but it remains incipient in buffalo. Therefore, this study aimed to (1) estimate variance components incorporating genomic information in Murrah buffalo; (2) evaluate the performance of genomic prediction for milk-related traits using single- and multitrait random regression models (RRM) and the single-step genomic best linear unbiased prediction approach; and (3) estimate longitudinal SNP effects and candidate genes potentially associated with time-dependent variation in milk, fat, and protein yields, as well as somatic cell score (SCS) in multiple parities. The data used to estimate the genetic parameters consisted of a total of 323,140 test-day records. The average daily heritability estimates were moderate (0.35 ± 0.02 for milk yield, 0.22 ± 0.03 for fat yield, 0.42 ± 0.03 for protein yield, and 0.16 ± 0.03 for SCS). The highest heritability estimates, considering all traits studied, were observed between 20 and 280 d in milk (DIM). The genetic correlation estimates at different DIM among the evaluated traits ranged from -0.10 (156 to 185 DIM for SCS) to 0.61 (36 to 65 DIM for fat yield). In general, direct selection for any of the traits evaluated is expected to result in indirect genetic gains for milk yield, fat yield, and protein yield but also increase SCS at certain lactation stages, which is undesirable. The predicted RRM coefficients were used to derive the genomic estimated breeding values (GEBV) for each time point (from 5 to 305 DIM). In general, the tuning parameters evaluated when constructing the hybrid genomic relationship matrices had a small effect on the GEBV accuracy and a greater effect on the bias estimates. The SNP solutions were back-solved from the GEBV predicted from the Legendre random regression coefficients, which were then used to estimate the longitudinal SNP effects (from 5 to 305 DIM). The daily SNP effect for 3 different lactation stages were performed considering 3 different lactation stages for each trait and parity: from 5 to 70, from 71 to 150, and from 151 to 305 DIM. Important genomic regions related to the analyzed traits and parities that explain more than 0.50% of the total additive genetic variance were selected for further analyses of candidate genes. In general, similar potential candidate genes were found between traits, but our results suggest evidence of differential sets of candidate genes underlying the phenotypic expression of the traits across parities. These results contribute to a better understanding of the genetic architecture of milk production traits in dairy buffalo and reinforce the relevance of incorporating genomic information to genetically evaluate longitudinal traits in dairy buffalo. Furthermore, the candidate genes identified can be used as target genes in future functional genomics studies.


Assuntos
Búfalos , Leite , Animais , Búfalos/genética , Feminino , Genômica , Lactação/genética , Fenótipo , Gravidez
6.
Trop Anim Health Prod ; 53(1): 145, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33511501

RESUMO

Beta-casein is a milk protein that has two variants: A1 and A2. Some individuals have difficulties digesting beta-casein A1, which can cause gastrointestinal disorders. A2 milk has emerged as an alternative. This milk only contains beta-casein A2 and is obtained from females carrying the A2A2 genotype of the gene. In cattle, allele and genotype frequencies vary according to breed and marker-assisted selection is performed to obtain A2A2 animals and the consequent production of A2 milk that is easier to digest. This study aimed to evaluate the alleles of beta-casein in buffaloes. A total of 657 buffaloes of four different breeds were genotyped and all animals carried the A2A2 genotype, i.e., allele A1 does not exist in the buffalo species. Thus, all milk products of buffaloes are naturally A2. This result adds value to products derived from buffalo milk.


Assuntos
Búfalos , Caseínas , Animais , Búfalos/genética , Caseínas/genética , Bovinos/genética , Feminino , Genótipo , Leite , Proteínas do Leite
7.
Front Vet Sci ; 7: 568249, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33251259

RESUMO

Considering the importance of the diseases affecting the productive performance of animals in the dairy industry worldwide, it is necessary to implement tools that help to control and limit the occurrence of such diseases. As the increased somatic cell counts (SCC) are a direct expression of the inflammatory process, they are candidates to become the usual parameter for assessing udder health regarding milk quality and for monitoring mastitis incidences. Toll-Like Receptors are membrane proteins that play a key role in immunity, recognizing pathogens and, subsequently, activating immune responses. The present study was conducted to identify single nucleotide polymorphisms in the TLR4 gene of buffaloes and to analyze its associations with somatic cell counts. DNA samples of 120 Murrah buffaloes were used. The whole coding region of the TLR4 gene was amplified by polymerase chain reaction reactions and sequenced for polymorphism scanning. A total of 13 polymorphisms were identified for the sequenced regions of the TLR4, most of which are in the coding region. The association with the somatic cell score was highly significant (p < 0.001) for all identified polymorphisms of TLR4 gene (g.54621T>A, g.54429G>T, g.54407T>A, g.46616C>A, g.46613T>G, g.46612A>G, g.46611C>A, g.46609T>G, g.46541C>G, g.46526C>A, g.46516T>C, g.46376C>T, g.46372T>C). Therefore, it is suggested that the markers of the TLR4 gene can be used as molecular markers for mastitis resistance in buffaloes, due to their association with somatic cell counts.

9.
Reprod Domest Anim ; 55(11): 1565-1572, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32853485

RESUMO

In Brazil, water buffaloes have been used to produce milk for mozzarella cheese production. Consequently, the main selection criterion applied for the buffalo genetic improvement is the estimated mozzarella yield as a function of milk, fat and protein production. However, given the importance of reproductive traits in production systems, this study aimed to use techniques for identifying genomic regions that affect the age at first calving (AFC) and first calving interval (FCI) in buffalo cows and to select candidate genes for the identification of QTL and gene expression studies. The single-step GBLUP method was used for the identification of genomic regions. Windows of 1 Mb containing single-nucleotide polymorphisms were constructed and the 10 windows that explained the greatest proportion of genetic variance were considered candidate regions for each trait. Genes present into the selected windows were identified using the UOA_WB_1 assembly as the reference, and their ontology was defined with the Panther tool. Candidate regions for both traits were identified on BBU 3, 12, 21 and 22; for AFC, candidates were detected on BBU 6, 7, 8, 9 and 15 and for first calving interval on BBU 4, 14 and 19. This study identified regions with great contribution to the additive genetic variance of age at first calving and first calving interval in the population of buffalo cows studied. The ROCK2, PMVK, ADCY2, MAP2K6, BMP10 and GFPT1 genes are main candidates for reproductive traits in water dairy buffaloes, and these results may have future applications in animal breeding programs or in gene expression studies of the species.


Assuntos
Búfalos/genética , Reprodução/fisiologia , Animais , Cruzamento , Búfalos/fisiologia , Feminino , Fertilidade/fisiologia , Estudo de Associação Genômica Ampla/veterinária , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas
10.
Trop Anim Health Prod ; 52(6): 3889-3892, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32594353

RESUMO

The aim of this study was to evaluate the population structure of Brazilian buffaloes using of pedigree information. The pedigree used in the analyses included records of 16,915 animals. The population parameters were obtained through the ENDOG software. The estimates of mean of inbreeding (F) and average relatedness (AR) coefficients were 3.22% and 5.99%, respectively. The average generation interval was 6.39 years. The effective number of founders and ancestors was 28 and 22, respectively. In this study, we concluded that the selection of individuals with lower AR is necessary to avoid an increase in matings between inbreeding individuals in this population, in order to obtain greater genetic gain by selection.


Assuntos
Búfalos/genética , Variação Genética , Endogamia , Linhagem , Animais , Brasil , Feminino , Masculino , Densidade Demográfica
11.
Sci Rep ; 10(1): 8770, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471998

RESUMO

Highlighting genomic profiles for geographically distinct subpopulations of the same breed may provide insights into adaptation mechanisms to different environments, reveal genomic regions divergently selected, and offer initial guidance to joint genomic analysis. Here, we characterized similarities and differences between the genomic patterns of Angus subpopulations, born and raised in Canada (N = 382) and Brazil (N = 566). Furthermore, we systematically scanned for selection signatures based on the detection of autozygosity islands common between the two subpopulations, and signals of divergent selection, via FST and varLD tests. The principal component analysis revealed a sub-structure with a close connection between the two subpopulations. The averages of genomic relationships, inbreeding coefficients, and linkage disequilibrium at varying genomic distances were rather similar across them, suggesting non-accentuated differences in overall genomic diversity. Autozygosity islands revealed selection signatures common to both subpopulations at chromosomes 13 (63.77-65.25 Mb) and 14 (22.81-23.57 Mb), which are notably known regions affecting growth traits. Nevertheless, further autozygosity islands along with FST and varLD tests unravel particular sites with accentuated population subdivision at BTAs 7 and 18 overlapping with known QTL and candidate genes of reproductive performance, thermoregulation, and resistance to infectious diseases. Our findings indicate overall genomic similarity between Angus subpopulations, with noticeable signals of divergent selection in genomic regions associated with the adaptation in different environments.


Assuntos
Bovinos/genética , Genoma , Animais , Regulação da Temperatura Corporal/genética , Brasil , Cruzamento , Canadá , Bovinos/classificação , Resistência à Doença/genética , Marcadores Genéticos , Desequilíbrio de Ligação , Reprodução/genética , Especificidade da Espécie
12.
G3 (Bethesda) ; 10(7): 2327-2343, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32434754

RESUMO

The aim of this study was to analyze the genomic homology between cattle (Bos taurus) and buffaloes (Bubalus bubalis) and to propose a rearrangement of the buffalo genome through linkage disequilibrium analyses of buffalo SNP markers referenced in the cattle genome assembly and also compare it to the buffalo genome assembly. A panel of bovine SNPs (single nucleotide polymorphisms) was used for hierarchical, non-hierarchical and admixture cluster analyses. Thus, the linkage disequilibrium information between markers of a specific panel of buffalo was used to infer chromosomal rearrangement. Haplotype diversity and imputation accuracy of the submetacentric chromosomes were also analyzed. The genomic homology between the species enabled us to use the bovine genome assembly to recreate a buffalo genomic reference by rearranging the submetacentric chromosomes. The centromere of the submetacentric chromosomes exhibited high linkage disequilibrium and low haplotype diversity. It allowed hypothesizing about chromosome evolution. It indicated that buffalo submetacentric chromosomes are a centric fusion of ancestral acrocentric chromosomes. The chronology of fusions was also suggested. Moreover, a linear regression between buffalo and cattle rearranged assembly and the imputation accuracy indicated that the rearrangement of the chromosomes was adequate. When using the bovine reference genome assembly, the rearrangement of the buffalo submetacentric chromosomes could be done by SNP BTA (chromosome of Bos taurus) calculations: shorter BTA (shorter arm of buffalo chromosome) was given as [(shorter BTA length - SNP position in shorter BTA)] and larger BTA length as [shorter BTA length + (larger BTA length - SNP position in larger BTA)]. Finally, the proposed linkage disequilibrium-based method can be applied to elucidate other chromosomal rearrangement events in other species with the possibility of better understanding the evolutionary relationship between their genomes.


Assuntos
Búfalos , Genoma , Animais , Búfalos/genética , Bovinos/genética , Cromossomos , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único
13.
J Dairy Sci ; 103(3): 2677-2684, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31954559

RESUMO

The aim of this study was to characterize the proteins present in milk whey from buffaloes with and without subclinical mastitis using a proteomic approach to identify differentially expressed proteins as potential biomarkers for this disease. Whey from Murrah buffaloes with subclinical mastitis was compared with whey from healthy animals using liquid chromatography-tandem mass spectrometry. The annotated protein databases for Bubalus bubalis and Bos taurus were used in the analysis, and the gene annotations from the buffalo and bovine reference assemblies were also used. After integrating gene annotations from both buffaloes and bovines, a total of 1,033 proteins were identified, of which 156 were differentially expressed. Eighteen biological processes were annotated with Gene Ontology. Cathelicidin-3 was identified as a potential biomarker for subclinical mastitis. These results are important to the characterization of mastitis in the buffalo mammary gland and may aid in the development of tools for early diagnosis.


Assuntos
Peptídeos Catiônicos Antimicrobianos/análise , Mastite/veterinária , Proteínas do Leite/análise , Proteômica , Soro do Leite/química , Animais , Biomarcadores/análise , Búfalos , Bovinos , Cromatografia Líquida/veterinária , Feminino , Mastite/metabolismo , Mastite Bovina/metabolismo , Espectrometria de Massas em Tandem/veterinária , Proteínas do Soro do Leite/análise , Catelicidinas
14.
Trop Anim Health Prod ; 52(1): 415-423, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31385169

RESUMO

Animal breeding programs have used molecular genetic tools as an auxiliary method to identify and select animals with superior genetic merit for milk production and milk quality traits as well as disease resistance. Genes of the major histocompatibility complex (MHC) are important molecular markers for disease resistance that could be applied for genetic selection. The aim of this study was to identify single nucleotide polymorphisms (SNPs) and haplotypes in DRB2, DRB3, DMA, and DMB genes in Murrah breed and to analyze the association between molecular markers and milk, fat, protein and mozzarella production, fat and protein percentage, and somatic cell count. Two hundred DNA samples from Murrah buffaloes were used. The target regions of candidate genes were amplified by polymerase chain reaction (PCR) followed by sequencing and identification of polymorphisms. Allele and genotype frequencies, as well as linkage disequilibrium between SNPs, were calculated. Genotypes were used in association analyses with milk production and quality traits. Except for the DMA gene, identified as monomorphic, the other genes presented several polymorphisms. The DMB, DRB2, and DRB3 genes presented two, six, and seven SNPs, respectively. Fifty-seven haplotype blocks were constructed from 15 SNPs identified, which was used in association analyses. All the studied traits had at least one associated haplotype. In conclusion, it is suggested that the haplotypes found herein can be associated with important traits related to milk production and quality.


Assuntos
Búfalos/genética , Haplótipos , Complexo Principal de Histocompatibilidade/genética , Leite/química , Polimorfismo de Nucleotídeo Único , Animais , Búfalos/metabolismo , Feminino
15.
J Appl Genet ; 61(1): 113-115, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31673966

RESUMO

Growth traits are important for the profitability of buffalo breeding systems, since in general, these animals are raised both for meat and milk. In this study, the single-step genomic BLUP method was employed to prospect the genomic regions' associated with weight at standard ages of 100, 210, 365, and 550 days in a buffalo population, aiming to identify genes with stronger expression for those characteristics. We found 6, 1, 2, and 5 SNPs significantly associated (p value < 10-5) with weight at 100, 210, 365, and 550 days of age, respectively, where those SNPs respectively explained 0.164, 0.040, 0.044, and 0.213% of the additive variance of each trait. SNP AX-85099682 (BBU24) was significant for weight at 100, 210, and 365 days, indicating the existence of a possible QTL affecting the initial growth rate of buffaloes. All told, eight genes (CBLB, TRNAG-UCC, GADD45B, LOC112583811, MGAT4C, KCNMA1, SLC5A2, and TGFB1I1) were identified as candidates for the growth traits of buffaloes. However, molecular and gene expression studies are necessary to validate these genes for subsequent use in programs for genetic improvement of the species.


Assuntos
Búfalos/crescimento & desenvolvimento , Búfalos/genética , Estudo de Associação Genômica Ampla , Genômica/métodos , Característica Quantitativa Herdável , Animais , Variação Genética , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas
16.
Trop Anim Health Prod ; 52(1): 243-247, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31313019

RESUMO

This study was carried out to estimate genetic parameters for morphology, body weight, and tonic immobility traits in the red-winged tinamou (Rhynchotus rufescens). Information on 690 birds was used and genetic parameters were estimated using Bayesian methods under a multi-trait animal model. The following traits were considered in this study: tarsal length (TL), bill length (BL), wing length (WL), head width (HW), bill width (BW), mature weight (MW), weight at 90 days (W90), and tonic immobility (TI). The heritability showed estimates between 0.15 for wing length and 0.56 for bill length. Positive and negative genetic correlations were estimated, ranging from - 0.33 to 0.81. All the morphological, production, and behavioral traits studied will have moderate to high response to selection. The body weight at 90 days is a better alternative for use in breeding programs and its selection would not lead to an increase in the time of tonic immobility. Both the selection for weight gain and for reduction of tonic immobility time would lead to an increase in the size of the legs of the red-winged tinamou, which could be advantageous for thermal control of these birds in tropical systems.


Assuntos
Peso Corporal/genética , Resposta de Imobilidade Tônica , Paleógnatas/genética , Animais , Cruzamento , Hereditariedade , Paleógnatas/anatomia & histologia , Paleógnatas/fisiologia
17.
J Dairy Sci ; 103(2): 1642-1650, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31759604

RESUMO

This research aimed to estimate genetic parameters for milk yield and type traits [withers height (WH), croup height (CH), body length (BL), croup length (CL), iliac width (ILW), ischial width (ISW), and thoracic circumference] in Murrah buffaloes and to identify genomic regions related to type traits by applying a single-step genome-wide association study. Data used to estimate the genetic parameters consisted of 601 records of milk yield in the first lactation and the aforementioned type traits. For the single-step genome-wide association study, 322 samples genotyped with a 90K Axiom Buffalo Genotyping array (Thermo Fisher Scientific, Santa Clara, CA) were used. Bivariate analysis revealed that heritability for milk yield (kg) at 305 d was 0.31 ± 0.11, whereas it ranged from 0.22 ± 0.07 to 0.34 ± 0.09 for the studied conformation traits. Based on the percentages of genetic variance explained by windows of 10 markers, there were 16 genomic regions explaining more than 0.5% of the variance for WH, CH, BL, CL, ILW, ISW, and thoracic circumference. Between those regions, 4 were associated with more than 1 trait, suggesting pleiotropic roles for some genes of Bos taurus autosome (BTA) 12 on CL and WH, BTA13 on ISW and ILW, BTA23 on CH and BL, and BTA28 on ISW and BL. Most of these regions coincide with known quantitative trait loci for milk traits. Thus, further studies based on sequence data will help to validate the association of this region with type traits and likely identify the causal mutations.


Assuntos
Búfalos/genética , Estudo de Associação Genômica Ampla/veterinária , Leite , Animais , Pesos e Medidas Corporais/veterinária , Búfalos/anatomia & histologia , Bovinos , Indústria de Laticínios , Feminino , Genótipo , Lactação/genética , Locos de Características Quantitativas
18.
Reprod Domest Anim ; 54(5): 808-811, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30821009

RESUMO

The information of twin pregnancy frequencies in buffaloes is scarce in the literature. Evidence even indicates that twin pregnancies are not carried to term, but it does not seem to be the case. In this case report, the event of twin pregnancy in buffaloes is reported as well as its frequency. Twin birth is the presence of two or more embryos in a single gestation. Multiple births are uncommon in buffaloes since the species is uniparous. We studied a population of Murrah buffaloes in which slightly more than 13,000 births were observed. In this study, the frequency of occurrence of twin births in Murrah buffaloes was 0.14%. This low incidence impaired the estimation of genetic parameters. Twins can have advantages and disadvantages depending on the production system, which are discussed in this case report.


Assuntos
Búfalos/fisiologia , Prenhez , Gravidez Múltipla/fisiologia , Gravidez Múltipla/estatística & dados numéricos , Animais , Brasil , Fazendas , Feminino , Gravidez
19.
Reprod Domest Anim ; 54(4): 727-732, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30740786

RESUMO

The objective of this study was to evaluate the genotype-environment interaction effect on age at first calving in buffaloes. The records were analysed using two approaches: (a) standard animal model and (b) reaction norm model. For the reaction norm analysis, two environmental gradients were formed, using age of first calving or milk yield group contemporary average. The results showed differences in the heritability estimates when using the two approaches. The reaction norm model indicated high heritability in more favourable environments and low magnitude genetic correlations between extreme environments. Based on our findings, we verified the significance of the genotype-environment interaction effect on age at first calving in buffaloes.


Assuntos
Envelhecimento/fisiologia , Búfalos/genética , Interação Gene-Ambiente , Genótipo , Modelos Biológicos , Parto/genética , Envelhecimento/genética , Animais , Búfalos/fisiologia , Feminino , Parto/fisiologia , Gravidez
20.
Theriogenology ; 125: 12-17, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30368127

RESUMO

The objective of this study was to assess the accuracy of genomic predictions for female reproductive traits in Nellore cattle. A total of 1853 genotyped cows and 305,348 SNPs were used for genomic selection analyses. GBLUP, BAYESCπ, and IBLASSO were applied to estimate SNP effects. The pseudo-phenotypes used as dependent variables were: observed phenotype (PHEN), adjusted phenotype (CPHEN), estimated breeding value (EBV), and deregressed estimated breeding value (DEBV). Predictive abilities were assessed by the average correlation between CPHEN and genomic estimated breeding value (GEBV) and by the average correlation between DEBV and GEBV in the validation population. Regression coefficients of pseudo-phenotypes on GEBV in the validation population were indicators of prediction bias in GEBV. BAYESCπ showed higher predictive ability to estimate SNP effects and GEBV for all traits.


Assuntos
Bovinos/genética , Bovinos/fisiologia , Genômica , Animais , Feminino , Genótipo , Modelos Genéticos , Polimorfismo de Nucleotídeo Único , Gravidez
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