Explore the vast range of titles available.

Maternal effects in cattle genetics are defined as the causal influence of the phenotype or maternal genotype on the offspring’s phenotype by effects occurring when the genetic and environmental characteristics of the mother influence the phenotype of the offspring beyond the direct inheritance of genes. Its relevance has been strongly described in genetic models focused on the genetic improvement of preweaning traits in cow-calf beef cattle production systems. Here, basic concepts and the importance of maternal effects when using linear and animal model procedures for genetic evaluations of growth and live-weight traits in beef cattle are reviewed and discussed. A brief history of estimation methods from classical studies to recent studies used for the development of animal models for studying maternal effects is also provided. Some important biometric concepts for maternal effect estimation are described, and the antagonism between direct genetic effects and maternal effects, its biological basis, and sources of error in the estimation of direct genetic and maternal covariance are discussed. Finally, some genomic perspectives are presented.

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.

Background: The assessment of genetic diversity, population structure, as well as within and across breed relationships using DNA markers is essential to develop conservation and genetic improvement programs. Objective: To assess the genetic diversity and population structure of Criollo Lechero Tropical (CLT) and Romosinuano (ROMO) cattle breeds in Mexico and compare them with other Criollo and Spanish breeds. Methods: The study included CLT and ROMO genotypes from the 65k Axiom©BovMDv3 array. Genomic data of Criollo and Spanish breeds were retrieved from a repository. Genetic diversity across breeds was evaluated by pairwise Wright's FST, principal components, and structure analysis. Results: Observed and expected heterozygosity, inbreeding coefficient, and effective population size (Ne) were 0.31, 0.30, -0.018 and 56 in CLT, and 0.32, 0.31, -0.023 and 99 in ROMO, respectively. Wright's FST indicated that both breeds are related to American Criollo and some Spanish cattle. ROMO cattle showed more significant Spanish ancestry than CLT. Conclusions: This study presents novel evidence indicating that, although the Ne of these breeds is small, they are still diverse and can be used as genetic reservoirs in conservation programs.

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.

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. 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.

Channel catfish (Ictalurus punctatus) is one of the endemic fishes of North America with the greatest potential for aquaculture. Despite this, data of its current distribution is scare and many aspects of its dynamic and productive performance remain unknown. In the present study, results are reported from a literature search and field analysis for describing the current status of channel catfish in Mexico regarding its historical and current geographical distribution as well as the problems faced by fish farmers and production systems. We were able to identify a lack of information and indicators to properly assess the extent of the species natural habitat and its productive potential. The quality and availability of water are among the main problems of the industry. Food costs represent the larger cost-loss for producers and there is great heterogeneity on the management of both breeding and production farms. Much of the production dynamics follows a pattern of trial and error. It became clear the need to optimize and standardize the processes on the channel catfish production system and to properly characterize domestic and wild populations to maximize their potential.

The channel catfish is an important aquaculture species in Mexico mostly managed in traditional production systems. The state of Tamaulipas has been the source of diverse populations of channel catfish in the country, however there is no documentary evidence of this. Therefore, the objective of this study was to confirm the genetic origin of populations of channel catfish (Ictalurus punctatus) of west central Mexico by microsatellite DNA markers. The study included four domestic populations from Michoacán, Zacatecas and Jalisco and two reference founder populations from Tamaulipas and Coahuila. The analysis was performed with a panel of 13 microsatellites. Some parameters of diversity and population structure were evaluated. The six populations showed excess of heterozygotes and a coefficient endogamy FIS ≤ -0.014. The analysis of gene structure was determined by a paired comparison populations, and indicated the 5.92% of variation among populations (FST= 0.059, P < 0.001). The assessment approaches identified the population of Tamaulipas as the most likely genetic origin of channel catfish populations currently used in the evaluated states.

Channel catfish, Ictalurus punctatus, is one of the most important fish on Mexican aquaculture and despite its productive potential, there is very few information regarding the distribution of Ictalurus species in Mexican territory. Sequencing of Cytochrome Oxidase I gene has proved to be very useful for the identification of fish specimens and sub-products. In the present, we report the molecular identification of 93 feral, commercial and domestic catfish individuals. All domestic fish were positively identified as channel catfish. Commercial samples were identified as Ictalurus punctatus, Ictalurus lupus, and Ictalurus furcatus, providing evidence that catfish represents a generic label for separate fish species. We also report the presence of feral I. punctatus on eight novel locations within Mexican territory, I. lupus on three and I. furcatus in one. Thus, we propose that molecular identification by DNA barcoding represents a powerful tool in the study of catfish populations and sub-products.

The South-Central region of Mexico has experienced a sizeable introduction of purebred horses for recreational aims. A study was designed to assess effective population sizes and genetic diversity and to verify the genetic integrity of four horse breeds. Using a 12-microsatellite panel, Quarter Horse, Azteca, Thoroughbred and Creole (CRL) horses were sampled and analysed for diversity and genetic structure. Genetic diversity parameters showed high numbers of heterozygous horses but small effective population sizes in all breeds. Population structure results suggested some degree of admixture of CRL with the other reference breeds. The highly informative microsatellite panel allowed the verification of diversity in introduced horse populations and the confirmation of small effective population sizes, which suggests a risk for future breed integrity.

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.