RESUMO

The aim of this study was to estimate the (co)variance components and genetic parameters for milk yield adjusted to 305d (MY305), calving-to-conception interval (CCI), number of services per conception (NSC) and calving interval (CI) of Honduran Holstein cows, by fitting a bivariate animal model using Maximum Restricted Likelihood procedures. Model included the fixed effects of calving number, the contemporary calving group (farm-season-year of calving and the cow age as covariate). The estimated means and standard deviations for MY, CCI, NSC and CI were, 5098.60 ± 1564.32 kg, 168.27 ± 104.71 days, 2.46 ± 1.69 services, and 448.73 ± 109.16 days, respectively; and their estimated heritabilities were 0.21 ± 0.05, 0.03 ± 0.028, 0.02 ± 0.024 and 0.06 ± 0.04, respectively. The genetic correlations between MY305 and CCI, NSC and CI were positive and antagonist, with values of 0.64 ± 0.52, 0.99 ± 0.56, and 0.32 ± 0.24 respectively. Even though moderate to low heritability was estimated for MY305, systematic selection for milk yield, with a reduction in reproductive efficiency, if considered as the only selection criterion is important to be considered. By including reproductive traits and considering permanent environment effects into the breeding program, might yield a slow, but constant and permanent improvement over time.

Assuntos

Lactação , Leite , Reprodução , Animais , Bovinos/genética , Bovinos/fisiologia , Lactação/fisiologia , Feminino , Leite/metabolismo , Honduras , Indústria de Laticínios , Cruzamento

RESUMO

Charolais is one of the most important beef cattle breeds in the world. In Mexico, it was introduced almost a century ago, and it has been suggested that particular breeding management and genetic material origin have caused a process of divergence among the current population. By a high-density SNP array genome-wide analysis, this study aimed to assess the proposed differentiation and population structure of local populations by genetic distances and structure approaches, and a European Charolais sample was included as a reference population. The differentiation statistics indicated that local populations exhibit moderate divergence, confirming a significant differentiation process between northeastern and northwestern Charolais populations (Fst≥ 0.043, D≥ 0.031). These results were strongly supported by PCA and structure analysis. Genetic isolation and low genetic flow between populations and divergent origins of introduced genetic material (i.e., semen) are likely the main drivers of the outcomes. Some implications are discussed.

Assuntos

Líquidos Corporais , Animais , Bovinos/genética , México , Sêmen

RESUMO

The 3' untranslated region has an important role in gene regulation through microRNAs, and it has been estimated that microRNAs regulate up to 50% of coding genes in mammals. With the aim of allelic variant identification of 3' untranslated region microRNA seed sites, the 3' untranslated region was searched for seed sites of four temperament-associated genes (CACNG4, EXOC4, NRXN3, and SLC9A4). The microRNA seed sites were predicted in the four genes, and the CACNG4 gene had the greatest number with 12 predictions. To search for variants affecting the predicted microRNA seed sites, the four 3' untranslated regions were re-sequenced in a Brahman cattle population. Eleven single nucleotide polymorphisms were identified in the CACNG4, and eleven in the SLC9A4. Rs522648682:T>G of the CACNG4 gene was located at the predicted seed site for bta-miR-191. Rs522648682:T>G evidenced an association with both exit velocity (p = 0.0054) and temperament score (p = 0.0097). The genotype TT had a lower mean exit velocity (2.93 ± 0.4 m/s) compared with the TG and GG genotypes (3.91 ± 0.46 m/s and 3.67 ± 0.46 m/s, respectively). The allele associated with the temperamental phenotype antagonizes the seed site, disrupting the bta-miR-191 recognition. The G allele of CACNG4-rs522648682 has the potential to influence bovine temperament through a mechanism associated with unspecific recognition of bta-miR-191.

Assuntos

MicroRNAs , Bovinos/genética , Animais , MicroRNAs/genética , Regiões 3' não Traduzidas/genética , Temperamento , Genótipo , Fenótipo , Mamíferos/genética

RESUMO

The objective of this study was to evaluate the effect of intronic single nucleotide polymorphisms (SNP) on temperament traits in a Brahman cattle population. The SNP located in CACNG4, EXOC4, NRXN3, and SLC9A4 candidate genes were genotyped in 250 animals with temperament records of exit velocity, pen score, and temperament score. Rs3423464051:G>A in the CACNG4 gene was associated with exit velocity and temperament score. An in silico analysis of the five intronic SNP showed that alternative alleles of CACNG4-rs3423464051, EXOC4-rs109393235, and SLC9A4-rs109722627 SNP could alter branch point sites during splicing, while a protein-protein interaction network analysis demonstrated a GRIA2 gene-mediated interaction between CACNG4 and NRXN3. The present results support previously reported evidence regarding bovine temperament-related candidate genes, particularly CACNG4, which is a confirmed candidate gene in need of more detailed analyses to reveal its role in temperament-related traits.(AU)

Assuntos

Animais , Comportamento Animal/fisiologia , Bovinos/genética , Polimorfismo de Nucleotídeo Único/genética , Temperamento , Marcadores Genéticos

RESUMO

Resumen Coronavirus 19 (COVID-19), es una enfermedad viral prevalente y diseminada a nivel mundial, considerada una pandemia con alta tasa de mortalidad. A la fecha no existen estudios que describan la influencia de las variables asociadas a la enfermedad en el estado fronterizo de Tamaulipas, México. El objetivo del presente estudio fue evaluar y analizar las características, complicaciones, tasas de letalidad y factores de riesgo asociados a mortalidad en paciente positivos a COVID-19 en el estado de Tamaulipas, a un año de la emergencia local. Se utilizó la frecuencia de casos observados en relación a características, complicaciones y comorbilidades para estimar prevalencias y tasas de letalidad. Se ajustó un modelo de regresión logística multivariada para estimar los factores de riesgo significativos y se utilizaron curvas de supervivencia de Kaplan-Meier para describir las comorbilidades más importantes. Los análisis indicaron una mayor infección en pacientes en edad productiva, con una probabilidad significativa de muerte a partir de los 40 años, más evidente en pacientes masculinos. Los riesgos asociados a la hospitalización, como intubación endotraqueal y neumonía, son factores muy importantes. Las comorbilidades con alta prevalencia (diabetes, hipertensión y obesidad) y enfermedad renal crónica (ERC) están asociados significativamente (P < 0.01) a mayor mortalidad por COVID-19 en pacientes positivos. El presente estudio demostró algunos patrones generales de prevalencia y tasas de letalidad por COVID-19, por lo que se sugieren particularidades en los factores asociados a mortalidad en la población de Tamaulipas que requieren atención en sus grupos vulnerables, sobre todo en posibles casos de rebrotes de la enfermedad.

---

Abstract Coronavirus 19 (COVID-19) is a prevalent and globally disseminated viral disease that has become a pandemic associated with a high case fatality rate. To date, there are no published studies that describe the influence of the variables associated with the disease, specifically in the border state of Tamaulipas, Mexico. The objective of the present study was to assess the characteristics, complications, fatality rates and risk factors associated to mortality in patients positive to COVID-19 in Tamaulipas, one year after the local emergency. Descriptive frequency of characteristics, complications for prevalence and case fatality rates were used. A multivariate logistic regression model was adjusted to estimate the meaningful risk factors, and Kaplan-Meier survival curves were used to describe the most important comorbidities. The analysis indicated higher infection rates in patients of productive age, with a significant death probability in male patients from the age of 40. The risks associated with hospitalization, such as endotracheal intubation and the presence of pneumonia are important risk factors. Comorbidities with high prevalence; diabetes, hypertension, obesity, and chronic kidney disease (CKD) were significantly associated (P < 0.01) with higher COVID-19 mortality risk in the assessed population. The present study demonstrated some COVID-19 general patterns on frequency and mortality rates. It also suggested particularities in factors associated to mortality in the Tamaulipas population, which require proper attention in vulnerable groups, especially in future outbreaks of the disease.

RESUMO

Introducción: La COVID-19 es una enfermedad viral diseminada a nivel mundial, que es considerada una pandemia con alta tasa de mortalidad, cuyo estudio epidemiológico es fundamental para entender el riesgo asociado a poblaciones específicas. Objetivos: Estimar las tasas de letalidad y factores de riesgo asociados a mortalidad por COVID-19 en cinco Estados con más contagios en México. Métodos: Se analizaron de 297 230 pacientes positivos a COVID-19 mediante prueba de RT-PCR procedentes de 475 unidades de monitoreo en cinco Estados de México. Se estimaron tasas de letalidad y razones de probabilidad mediante el ajuste de un modelo de regresión logística multivariada. Se consideraron los factores de riesgo en un modelo que incluyó los efectos del sexo, edad, hábitos de fumador, historial de hospitalización, diagnóstico de neumonía y comorbilidades como diabetes, hipertensión, enfermedad pulmonar obstructiva crónica, asma, inmunodepresión, enfermedad renal crónica y enfermedades cardiovasculares, entre otras. Resultados: Existe mayor contagio entre las personas de 41 a 60 años de edad. Más del 90 por ciento de los fallecimientos ocurrieron después de los 41 años, con aumento de la tasa de letalidad a mayor edad. Los hombres mostraron mayor proporción de casos, fallecimientos y tasa de letalidad. El análisis logístico multivariado mostró que la edad, sexo, hospitalización, neumonía, diabetes y enfermedad renal crónica son factores de riesgo significativos (p < 0,0001) para mortalidad por COVID-19. Conclusiones: En México la edad, el sexo, la hospitalización, neumonía, diabetes y enfermedad renal crónica son factores que aumentan el riesgo de mortalidad por COVID-19. Se sugiere tener en cuenta esta información para determinar los grupos vulnerables e incrementar la atención sobre ellos para disminuir, en la medida de lo posible, el riesgo de contagio y mortalidad(AU)

---

Introduction: COVID-19 is a viral disease disseminated worldwide, considered a pandemic with a high mortality rate, whose epidemiological study is fundamental to understand the risk associated with specific populations. Objectives: Estimate the case fatality rates and risk factors associated with mortality from COVID-19 in the five states with more infections in Mexico. Methods: 297,230 COVID-19 positive patients were analyzed using RT-PCR tests from 475 monitoring units in five states of Mexico. Case fatality rates and probability ratios were estimated by adjusting a multivariate logistic regression model. Risk factors were considered in a model that included the effects of sex, age, smoking habits, hospitalization history, pneumonia diagnosis, and comorbidities such as diabetes, hypertension, chronic obstructive pulmonary disease, asthma, immunosuppression, chronic kidney disease, and cardiovascular disease, among others. Results: There is greater contagion among people aged 41 to 60 years. More than 90percent of deaths occurred after the age of 41, with the case fatality rate increasing at an older age. Men showed a higher proportion of cases, deaths and case fatality rate. Multivariate logistic analysis showed that age, sex, hospitalization, pneumonia, diabetes, and chronic kidney disease are significant risk factors (p < 0.0001) for COVID-19 mortality. Conclusions: In Mexico, age, sex, hospitalization, pneumonia, diabetes and chronic kidney disease are factors that increase the risk of mortality from COVID-19. It is suggested to take this information into account to determine vulnerable groups and increase attention to them to reduce, as far as possible, the risk of contagion and mortality(AU)

Assuntos

Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Fatores de Risco , COVID-19/mortalidade , México

RESUMO

A genome-wide association study (GWAS) was performed to elucidate genetic architecture of growth traits in Braunvieh cattle. Methods: The study included 300 genotyped animals by the GeneSeek® Genomic Profiler Bovine LDv.4 panel; after quality control, 22,734 SNP and 276 animals were maintained in the analysis. The examined phenotypic data considered birth (BW), weaning (WW), and yearling weights. The association analysis was performed using the principal components method via the egscore function of the GenABEL version 1.8-0 package in the R environment. The marker rs133262280 located in BTA 22 was associated with BW, and two SNPs were associated with WW, rs43668789 (BTA 11) and rs136155567 (BTA 27). New QTL associated with these liveweight traits and four positional and functional candidate genes potentially involved in variations of the analyzed traits were identified. The most important genes in these genomic regions were MCM2 (minichromosome maintenance complex component 2), TPRA1 (transmembrane protein adipocyte associated 1), GALM (galactose mutarotase), and NRG1 (neuregulin 1), related to embryonic cleavage, bone and tissue growth, cell adhesion, and organic development. This study is the first to present a GWAS conducted in Braunvieh cattle in Mexico providing evidence for genetic architecture of assessed growth traits. Further specific analysis of found associated genes and regions will clarify its contribution to the genetic basis of growth-related traits.

Assuntos

Bovinos/crescimento & desenvolvimento , Bovinos/genética , Variação Genética , Animais , Animais Recém-Nascidos , Peso ao Nascer/genética , Feminino , Genética Populacional , Estudo de Associação Genômica Ampla/veterinária , Genótipo , Masculino , México , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Desmame

RESUMO

Chronic kidney disease (CKD) is a recognized public health problem and key determinant of poor health outcomes. In Mexico, this condition has been associated with high and significant risk of death in COVID-19 patients; however, not enough attention has been given to the vulnerable population as the increasing numbers and fatality rates suggest. This study evaluated the effect of interaction between CKD condition and other risk factors (sex, diabetes, hypertension and obesity) on the survival rate of positive patients for COVID-19 in Mexico. The results from this study support that CKD patients is a population at high risk for mortality for COVID-19 and that COVID-19 positive inpatients with CKD and diabetes are highly vulnerable to death.

Assuntos

COVID-19 , Mortalidade , Insuficiência Renal Crônica , COVID-19/diagnóstico , COVID-19/epidemiologia , Teste para COVID-19/estatística & dados numéricos , Comorbidade , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Prognóstico , Diálise Renal/métodos , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/terapia , Medição de Risco/estatística & dados numéricos , Fatores de Risco , SARS-CoV-2/isolamento & purificação , Taxa de Sobrevida

RESUMO

Abstract The aim of this study was to estimate allelic and genotypic frequencies of markers in the leptin (LEP), pituitary transcription factor (PIT-1) and luteinizing hormone receptor (LHR) genes and evaluate their effects on reproductive traits and milk yield of Holstein cattle. Data from 147 cows from department of Francisco Morazán, Honduras, were collected and PCR-Restriction Fragment Length Polymorphism (RFLP) assays were performed to characterize the PIT-1-HinfI, LEP- A59V and LHR-rs41256848 polymorphisms. To estimate the effect of genotypes on reproductive traits and milk yield fixed and mixed linear models were fitted. The frequencies of the genotypes CC, CT and TT of A59V, AA, AB and BB of HinfI, and CC, CG and GG of rs41256848 were 0.46, 0.33 and, 0.21; 0.09, 0.32 and 0.58; and 0.37, 0.61 and 0.02, respectively. The genotypes of LEP and LHR showed deviations from Hardy-Weinberg equilibrium. The A59V polymorphism was significantly associated with the calving to conception interval (CCI) (p=0.01), being the C allele favorable. The HinfI and rs41256848 polymorphism were significantly associated (p=0.08 and p=0.04) with age to first calving (AFC), being the A and G the alleles favorable associated, respectively. The results suggest that LEP, PIT and LHR polymorphisms can probably act as candidate to be used in marker-assisted selection for AFC and CCI traits.

Assuntos

Hormônio Luteinizante , Leptina , Perfil Genético , Frequência do Gene/fisiologia , Reprodução , Bovinos , Reação em Cadeia da Polimerase/instrumentação

RESUMO

PURPOSE: The purpose of this study was to assess clinical characteristics and risk factors for mortality of patients with coronavirus disease 2019 (COVID-19) from Mexico, given that it currently is in active community transmission. METHODS: Multivariate logistic regression model and Kaplan-Meier survival curves were fitted to study odds of death of characteristics and comorbidities in patients with COVID-19 in Mexico. RESULTS: Age, sex, and the most frequent comorbidities diabetes, obesity, and hypertension were significantly associated to the risk of death by COVID-19 (P < .0001). Smoking habit was not identified as a risk factor for death. Less-frequent comorbidities such as chronic obstructive pulmonary disease, chronic kidney disease, and patients with immunosuppressed conditions also showed a significant risk for death (P < .0001). Hospitalized patients and those with pneumonia had serious risks for mortality (P < .0001), and more attention to specific conditions might be considered during clinical admission. CONCLUSIONS: A more vulnerable positive patient is depicted by a male patient, older than 41 years, which increases their risk with more prevalent comorbidities such as diabetes, hypertension, and obesity. Some implications on outcomes are discussed.

Assuntos

Infecções por Coronavirus/mortalidade , Diabetes Mellitus/mortalidade , Hipertensão/epidemiologia , Obesidade/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Asma/epidemiologia , Betacoronavirus/isolamento & purificação , COVID-19 , Doenças Cardiovasculares/epidemiologia , Criança , Pré-Escolar , Comorbidade , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Diabetes Mellitus/epidemiologia , Humanos , Hospedeiro Imunocomprometido , Lactente , Recém-Nascido , Estimativa de Kaplan-Meier , México/epidemiologia , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/epidemiologia , Prevalência , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Insuficiência Renal Crônica/epidemiologia , SARS-CoV-2 , Fatores Sexuais , Fumar/epidemiologia , Adulto Jovem

RESUMO

Resequencing of Myostatin, Growth Hormone, Follistatin-A-like, Insulin-like Growth Factor I (IGF-I) and Myogenin (MYOG) genes was completed to discover novel genetic variations and assess non synonymous (ns) polymorphisms (SNPs) effect on growth related traits of channel catfish. Wild and farmed animals were used as a discovering population. Resequencing lead to the identification of 59 new variants in the five analyzed genes; 66% found in introns and 34% in coding regions. From coding regions, 14 variants were synonyms and six were ns variations. A mutation rate of one in 129 bp was estimated. Four ns variations were selected for validation and association analysis. In IGF-I two ns polymorphisms, at IGF-I19 the G wild type allele was fixed in population and for IGF-I63 the C allele had a frequency of 0.972 and for mutate allele G of 0.027. In MYOG two ns SNPs were assessed. MYOG131 presented a frequency of alleles T and A, of 0.754 and 0.246, respectively and MYOG233, with a frequency of G and C of 0.775 and 0.225, respectively. Only MYOG131 (g.529T>A) was significantly associated (P < 0.04) to some growth traits. Results suggest MYOG131 g.529T>A as candidate locus for genetic enhancement of growth traits in channel catfish.

Assuntos

Crescimento e Desenvolvimento/genética , Ictaluridae/genética , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Animais , Proteínas Relacionadas à Folistatina/genética , Hormônio do Crescimento/genética , Ictaluridae/crescimento & desenvolvimento , Fator de Crescimento Insulin-Like I/genética , Miogenina/genética , Miostatina/genética

RESUMO

We investigated whether a panel of molecular markers previously associated with temperament has an effect on live growth traits. Phenotypic data from 412 Charolais cows categorized according to their age in adult and young cows were used to determine Pearson's correlations between birth (BW), weaning (WW), and yearling live (YW) weight and temperament traits (measured as exit velocity [EV] and temperament score [TS]). For association analysis, selective genotyping of a group of 80 cows identified as the most docile and temperamental were genotyped with a 151-SNP (single-nucleotide polymorphisms) panel of molecular markers previously associated with temperament. Significant Pearson's correlations between birth weight and weaning weight and the two temperament measurements (EV and TS) were observed only in the young cow group. Significant effects of ten SNP on BW and WW were observed. Four markers located on candidate genes for temperament traits also had an effect on birth weight and weaning weight in Charolais cows, which indicates that both traits could be influenced by the same genes.(AU)

Assuntos

Animais , Feminino , Temperamento/fisiologia , Comportamento Animal , Bovinos/fisiologia , Genes , Peso Corporal/genética

RESUMO

Heritable abnormalities can cause a reduction in productive performance, structural defects, or death of the animal. There are reports of hereditary abnormalities in Braunvieh cattle from several countries, but no evidence was found on their existence in Mexico. In this study, 28 genes associated with hereditary diseases were screened with the GGP-LD 30K array (GeneSeek®) in 300 Mexican registered Braunvieh animals. Allelic frequencies of the markers associated with illness were obtained for the following: citrullinaemia, spinal dysmyelination, spinal muscular atrophy, Brows Swiss fertility haplotype 2, congenital muscular dystonia, epidermolysis bullosa, Pompes, maple syrup urine, syndactyly, Weaver syndrome, crooked tail, deficiency of uridine monophosphate synthase, hypotrichosis, Marfan syndrome, and weak calf syndrome. The allelic frequency values were low for all the analysed loci (from 0.0015 to 0.0110), with exception of syndactyly (0.4145). Although homozygous animals for these genetic conditions were detected, no physical or physiological abnormalities associated with the clinical form of the diseases were observed in the sampled animals. Markers associated with a crooked tail, deficiency of uridine monophosphate synthase, hypotrichosis, Marfan syndrome, and weak calf syndrome were absent. The studied Mexican Braunvieh population does not present clinical or subclinical effects for ten diseases in homozygous animals. However, since the assessed animals are considered as breeding stock, the monitoring of carrier animals might be periodically necessary.

Assuntos

Doenças dos Bovinos/genética , Predisposição Genética para Doença , Animais , Bovinos , Feminino , Fertilidade , Marcadores Genéticos , Haplótipos , México , Prevalência

RESUMO

ABSTRACT The signals of selection using candidate genes polymorphism were studied in five zebu breeds of Mexico. Three loci from GHRH and complementarily Steroyl Co Desaturase F762, Dopamine Beta Hydroxilase 17299, and LEP3272 were identified under selection. Findings depict Zebu selection pressure mainly on Brahman breed resulting in a divergent structure pattern.

RESUMO

Background The Zebu cattle are represented by a diverse group of breeds in México. Traditionally these breeds have been associated with the tough beef characteristic. Validated genetic markers have the potential to be included in marker-assisted selection and management programs in order to improve traits such as beef tenderness. The incidence and distribution of Calpain and Calpastatin polymorphisms strongly associated with beef tenderness were estimated in registered cattle of five Zebu breeds in Mexico. Results A low and in some cases null frequency of favorable C allele of CAPN316 was determined in all breeds. Conversely, a more equilibrated frequency in CAPN4751 and CAST loci was observed. Conclusions Although the relatively low occurrence of favorable alleles in assessed loci may limit their use in selection programs, genotyping availability might be a practical and comprehensive tool for introgression programs by marker assisted selection and management as to improve meat tenderness of Zebu breeds.

Assuntos

Animais , Bovinos , Polimorfismo Genético , Bovinos/genética , Carne , Calpaína/genética , Marcadores Genéticos , Alelos , Frequência do Gene , Genótipo , Produtos da Carne , México

RESUMO

BACKGROUND: For most domestic animal species, including bovines, it is difficult to identify causative genetic variants involved in economically relevant traits. The candidate gene approach is efficient because it investigates genes that are expected to be associated with the expression of a trait and defines whether the genetic variation present in a population is associated with phenotypic diversity. A potential limitation of this approach is the identification of candidates. This study used a bioinformatics approach to identify candidate genes via a search guided by a functional interaction network. RESULTS: A functional interaction network tool, BosNet, was constructed for Bos taurus. Predictions for candidate genes were performed using the guilt-by-association principle in BosNet. Association analyses identified five novel markers within BosNet-prioritized genes that had significant effects on different growth traits in Charolais and Brahman cattle. CONCLUSIONS: BosNet is an excellent tool for the identification of single nucleotide polymorphisms that are potentially associated with complex traits.

Assuntos

Biologia Computacional/métodos , Epistasia Genética , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Característica Quantitativa Herdável , Alelos , Animais , Cruzamento , Bovinos , Frequência do Gene , Genômica , Genótipo

RESUMO

The objective of the present experiment work was to evaluate the effect of the inclusion of genomic information on the additive genetic variance of birth weight (BW) of Charolais cattle in Mexico. Variance components and heritability were estimated using four linear models. The first model was the base model (BM) from which single and composite effects of selected single-nucleotide polymorphism (SNP) markers were evaluated (BM1, BM2, and a composite BM3). Genetic markers were included in a regression model and analyzed by stepwise regression against adjusted BW from a panel of growth-related traits candidate gene markers. After two regression rounds, two SNPs (R (2) > 0.02) were chosen to include into the animal models as fixed effects. Growth hormone receptor gene GHR 4.2 and GHR 6.1 SNPs were selected from a panel of 39 SNPs. GHR 4.2 had a negligible effect on BW, whilst GHR6.1, interestingly, explained ∼9 % of genetic variance (p = 0.0877) with an αG>A = 0.509. The inclusion of markers in M2 and M3 reduced 19 and 15 % of the additive genetic variance, respectively. Both adjusted significantly better the linear model (LRT = p < 0.01). Results obtained suggest that the previous selection of markers in a candidate gene approach and subsequent inclusion of selected SNPs into animal model might provide a better fit, avoiding the overestimation of genetic variance components and breeding values for BW.

Assuntos

Peso ao Nascer/genética , Bovinos/crescimento & desenvolvimento , Bovinos/genética , Polimorfismo de Nucleotídeo Único , Aumento de Peso/genética , Animais , Marcadores Genéticos , Masculino , México , Modelos Genéticos , Fenótipo

RESUMO

DNA from four cattle breeds was used to re-sequence all of the exons and 56% of the introns of the bovine tyrosine hydroxylase (TH) gene and 97% and 13% of the bovine dopamine ß-hydroxylase (DBH) coding and non-coding sequences, respectively. Two novel single nucleotide polymorphisms (SNPs) and a microsatellite motif were found in the TH sequences. The DBH sequences contained 62 nucleotide changes, including eight non-synonymous SNPs (nsSNPs) that are of particular interest because they may alter protein function and therefore affect the phenotype. These DBH nsSNPs resulted in amino acid substitutions that were predicted to destabilize the protein structure. Six SNPs (one from TH and five from DBH non-synonymous SNPs) were genotyped in 140 animals; all of them were polymorphic and had a minor allele frequency of > 9%. There were significant differences in the intra- and inter-population haplotype distributions. The haplotype differences between Brahman cattle and the three B. t. taurus breeds (Charolais, Holstein and Lidia) were interesting from a behavioural point of view because of the differences in temperament between these breeds.

RESUMO

Se aplicó un panel de nueve marcadores microsatélites para estructurar la genealogía de un hato de ganado Braford manejado bajo empadre múltiple y destinado a pié de cría, para evaluar las repercusiones de la adecuada asignación de progenitores, así como las implicaciones en su mejoramiento genético. Se logró la asignación de paternidad en el 100% de la progenie, mientras que en los ensayos de verificación de maternidad se estimó un porcentaje de error de asignación de aproximadamente 90%. Los resultados encontrados apoyan el uso de la asignación de paternidad para verificar la estructura genealógica (paternidad y maternidad) de hatos cuya certeza en el pedigrí es crítica para el mejoramiento genético de su raza, y en donde el sistema de manejo extensivo y empadre múltiple limitan el registro adecuado de la progenie al momento del parto.

---

To assess the implications of parentage assignation on herds-genetic improvement nine microsatellite markers were used in order to structure the genealogy of a multisired Braford herd. All progeny (100%) had satisfactory paternity assignment, conversely the maternity verification analysis showed assignation errors up to 90%. Our results support the use of molecular tools to verify the pedigree structure in those herds with management systems that limit the proper registration of progeny at calving.

RESUMO

The aim of this study was to estimate genetic parameters for growth traits in Mexican Nellore cattle. A univariate animal model was used to estimate (co)variance components and genetic parameters. The traits evaluated were birth weight (BW), weaning weight (WW), and yearling weight (YW). Models used included the fixed effects of contemporary groups (herd, sex, year, and season of birth) and age of dam (linear and quadratic) as a covariate. They also included the animal, dam, and residual as random effects. Phenotypic means (SD) for BW, WW, and YW were 31.4 (1.6), 175 (32), and 333 (70) kg, respectively. Direct heritability, maternal heritability, and the genetic correlation between additive direct and maternal effects were 0.59, 0.17, and -0.90 for BW; 0.29, 0.17, and -0.90 for WW; and 0.24, 0.15, and -0.86 for YW, respectively. The results showed moderate direct and maternal heritabilities for the studied traits. The genetic correlations between direct and maternal effects were negative and high for all the traits indicating important tradeoffs between direct and maternal effects. There are significant possibilities for genetic progress for the growth traits studied if they are included in a breeding program considering these associations.

Assuntos

Peso Corporal/genética , Bovinos/crescimento & desenvolvimento , Bovinos/genética , Modelos Genéticos , Animais , Feminino , Masculino , México