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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.

A genome-wide association study (GWAS) for liveweight traits of Braunvieh cattle was performed. 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, weaning, 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 birth weight, and two SNPs were associated with weaning weight, 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), with relationships with 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 and represents a basis for future research. Further analyses of found associated regions will clarify its contribution to the genetic basis of growth-related traits.

OBJECTIVE From a review of published information on genetic association studies, a meta-analysis was conducted to determine the influence of the genes κ-casein (CSN3) and β-lactoglobulin (LGB) on milk yield traits in Holstein, Jersey, Brown Swiss, and Fleckvieh. METHODS The GLIMMIX procedure was used to analyze milk production and percentage of protein and fat in milk. Models included the main effects and all their possible two-way interactions; not estimable effects and non-significant (p>0.05) two-way interactions were dropped from the models. The three traits analyzed used Poisson distribution and a log link function and were determined with the Interactive Data Analysis of SAS software. Least square means and multiple mean comparisons were obtained and performed for significant main effects and their interactions (p

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.

The objective was to estimate the allelic and genotypic frequencies, genetic diversity and polymorphic information content for the β-casein, κ-casein and β-lactoglobulin genes. Blood and frozen semen samples were collected from 453 Jersey individuals registered by the Mexican Jersey Cattle Association. Twenty eight breed specific SNP primers for whole genes were used. The B allele of κ-casein had higher frequency (0.69) than the A (0.26) and E (0.05). For β-lactoglobulin, the highest frequency was for B (0.72), followed by A and C alleles (0.26 and 0.02, respectively). The β-casein allele with the highest frequency was A² (0.71), followed by A¹ (0.19), A³ (0.05), B (0.04) and C (0.01). The average genetic diversity (He) was 0.53. The average locus effective allele number was 1.79. These results indicate a high allelic diversity for κ-caseín, β-casein and β-lactoglobulin that could be included in breeding programs in the population studied, aimed to improve the milk quality traits of economic importance.

The genomic and transcriptomic analyses for selection and genetic improvement require DNA or RNA of hig concentration and purity, coming from different tissues, including semen. The DNA may be from hair, saliva, cartilage, blood, or semen. The methods usually used to extract DNA from semen have low efficiency in terms of quantity and quality. This is due to the solvents and dilutors used for semen conservation, physical and chemical characteristics of sperms, and non-cellular fraction of ejaculate. In this study, modifications to the guanidinium thiocyanate method are proposed, including a second washing of the sample using a phosphate buffer solution, and two washing with organic solvents, one strong (phenol:chloroform:Isoamyl alcohol), and one weak (chloroform:isoamyl alcohol), to get rid of the protein and dilutors present in the sample. Additionally, it is proposed a separate incubation with RNA-ase to reduce contamination of nucleic acids during measurement and dilution preparation for PCR amplification. The precipitation added to the isopropanol of the original method 3 M sodium acetate to separate the residuals of potential PCR inhibitors. Finally, there were included high-speed centrifugation and decantation to avoid the need for mechanical separation of the DNA and protein. The DNA extracted with the modified method did not present degradation, and the quality and quantity were better (P