Monitoring of recessive defects associated with low reproductive performance in dairy cattle in Uruguay.

Background: Most dairy cattle breeds originate show an average generational inbreeding rate of 1%, which favors the occurrence of recessive defects associated with low reproductive performance. Aim: The objective of this study was to monitor recessive defects associated with low reproductive performance in dairy cattle. Methods: To monitor bulls carrying the Holstein Friesian haplotype (HH) 1, HH3, and HH4 haplotypes, we analyzed the records of 3,028 national and imported Holstein Friesian bulls from the 2021 updated sires' catalog published by "Evaluaciones Genéticas Lecheras"; and to determine the presence of these mentioned haplotypes, as well as Jersey haplotype (JH) 1 and complex vertebral malformation (CVM), were genotype with the GeneTitan® 2,500 single nucleotide polymorphism (SNP) bovine chip, estimate their frequencies and evaluate their impact on the fertility of 100 Holstein Friesian cows and 70 Holstein Friesian-Jersey crosses belonging to an experimental dairy. Results: From a total of 1,468 (48.5%) bulls with genetic information from the sires' catalog for HH1 and 1,471 (48.6%) for HH3 and HH4, we found 90 (6.1%) carriers for HH1, 60 (4.1%) for HH3, and 6 (0.4%) for HH4, respectively. By genotyping with the chip, we calculated the herd frequency of the mutant alleles and herd prevalence of carriers for HH1 and CVM as q = 0.003 and 0.022; 0.59% and 4.3% (call rate >0.99), respectively. No mutant alleles were found for HH3, HH4, and JH1 in the analyzed population. We examined reproductive data by observing the presence of CVM and HH1 mutant alleles in repeat cows with an average of four services to achieve pregnancy. Conclusion: This study demonstrated the presence of recessive defects associated with low reproductive performance in the analyzed population, which can affect the health and productivity of dairy cattle. Therefore, cows and bulls should be closely monitored through genetic testing to lower the incidence of recessive defects in dairy cattle.

Detection of the Brachyspina mutation in Uruguayan Holstein cows using real time PCR and melting curve analysis / Detecção da mutação da Brachyspina em vacas Holandês Uruguaias usando PCR em tempo real e análise da curva de fusão

ABSTRACT: Brachyspina syndrome (BS) is a rare monogenic autosomal recessive hereditary disorder of the Holstein Fresian breed caused by a deletion of 3.3Kb in the Fanconi anemia complementation group I (FANCI) gene on BTA-21, which leads to a frame-shift and premature stop codon. Some of the consequences of BS are the reduction of the fertility rate and milk production. This study developed a simple, sensitive, rapid cost- effective assay method based on real time PCR and melting curve analysis for the detection of BS carrier animals. Sixty-eight normal homozygous and four heterozygous carrier genotypes were detected and confirmed through traditional PCR- electrophoresis analysis. We concluded that the assay we have developed proved to be a reliable, highly precise and low-cost tool, which could be used to monitor the presence of the BS mutation in uruguayan Holstein breed.

RESUMO: A síndrome de Brachyspina (BS) é um defeito hereditário monogênico autossômico recessivo raro da raça Holstein Friesian causado por uma exclusão de 3,3 KB no gene FANCI localizado no cromossomo bovino 21, o que leva a um deslocamento de quadro e um códon de parada prematuro. Uma consequência da BS é a eficiência de reprodução reduzida e a produção de leite. O objetivo deste estudo foi o desenvolvimento de um método simples, rápido e sensível, baseado em PCR em tempo real e análise da curva de fusão para identificar animais portadores de BS. Sessenta e oito genótipos homozigotos normais e quatro heterozigotos foram detectados e confirmados através da análise tradicional de PCR e electophorese. Concluímos que o novo método é uma ferramenta confiável, altamente precisa e de baixo custo, que poderia ser usado para monitorar a presença da mutação BS na raça Holandês uruguaia.

Pilot study using the ECHO model to enhance linkage to care for patients with hepatitis C in the custodial setting.

Prisoners in most countries have a higher prevalence of HCV than the general population, but their access to treatment is very limited. Our aim was to evaluate a pilot programme using the ECHO model to enhance linkage to care in patients with HCV in 3 Argentinean prisons between October 2018 and January 2020. All inmates were invited to participate, and data were collected through a personal interview. We then estimated HCV prevalence with dried blood spot and performed a logistic regression analysis to identify risk behaviours associated with HCV infection. Finally, HCV management was assessed and monitored through ECHO. Overall, 1141 inmates agreed to participate, representing 39.7% of the total prison population. Anti-HCV prevalence was estimated at 1.58% (CI 0.93; 2.48), being significantly higher in women 2.98% (CI 1.4;5.6) than in men 1.07% (CI 0.5; 2.0); P = .03. Patients with anti-HCV were significantly older than those who tested negative, 42.3 years (CI 37.6;47.1) vs 30.1 years (CI 30.6;31.2), P < .001, respectively. Multiple logistic regression analysis, identified age OR 1.07 (CI 1.03;1.12, P = .001), history of sexually transmitted disease OR 3.08 (CI 0.97;9.82, P = .057) and intravenous drug use OR 12.6 (CI 3.31;48.53, P < .001) as risk factors associated with anti-HCV. Treatment was initiated in all the patients with specialist physician support utilizing ECHO model. In conclusion, our pilot study reported a low prevalence of anti-HCV in the studied population. Incarceration provides an ideal opportunity for testing and treating HCV. ECHO model arises as a useful tool to support assessment and treatment for inmates with chronic HCV.

Comparison of transcriptomic landscapes of different lamb muscles using RNA-Seq.

Transcriptome deep sequencing is a powerful tool for exploring the genetic architecture of complex traits. Gene expression patterns may explain a high degree of the observed phenotypic differences in histochemical and metabolic parameters related to meat quality among different muscles. In this study, we sequenced by RNA-Seq the whole transcriptome of nine lamb muscles: Semimembranosus (SM), Semitendinosus (ST), Cranial gluteobiceps, Gluteus medius (GM), Rectus femoris, Supraspinatus (SS), Longissimus lumborum (LL), Adductor and Psoas major. Significant gene expression differences were detected between almost all pairwise comparisons, being more pronounced between SS and ST, SM and LL, and ST and GM. These differences can be explained in terms of ATPase and glycolytic activities, muscle fiber typing and oxidative score, clustering muscles as fast glycolytic, intermediate or slow oxidative. ST showed up-regulation of gene pathways related to carbohydrate metabolism, energy generation and protein turnover as expected from a fast white muscle. SS showed myosin isoforms typical of slow muscles and high expression of genes related to calcium homeostasis and vascularization. SM, LL and GM showed in general intermediate gene expression patterns. Several novel transcripts were detected, mostly related to muscle contraction and structure, oxidative metabolism, lipid metabolism and protein phosphorylation. Expression profiles were consistent with previous histochemical and metabolic characterization of these muscles. Up-regulation of ion transport genes may account for significant differences in water holding capacity. High expression of genes related to cell adhesion, cytoskeleton organization, extracellular matrix components and protein phosphorylation may be related to meat yellowness and lower tenderness scores. Differential expression of genes related to glycolytic activity and lactic acid generation among fast, intermediate and slow muscles may explain the detected final meat pH differences. These results reveal new candidate genes associated with lamb meat quality, and give a deeper insight into the genetic architecture of these complex traits.

Whole-genome scan reveals significant non-additive effects for sire conception rate in Holstein cattle.

BACKGROUND: Service sire has a considerable impact on reproductive success in dairy cattle. Most gene mapping studies for bull fertility have focused on additive effects, while non-additive effects have been largely ignored. The main goal of this study was to assess the relevance of non-additive effects on Sire Conception Rate (SCR) in Holstein dairy cattle. The analysis included 7.5 k Holstein bulls with both SCR records and 57.8 k single nucleotide polymorphism (SNP) markers spanning the entire genome. RESULTS: The importance of non-additive effects was evaluated using an efficient two-step mixed model-based approach. Four genomic regions located on chromosomes BTA8, BTA9, BTA13 and BTA17 showed marked dominance and/or recessive effects. Most of these regions harbor genes, such as ADAM28, DNAJA1, TBC1D20, SPO11, PIWIL3 and TMEM119, that are directly implicated in testis development, male germ line maintenance, and sperm maturation. CONCLUSIONS: This study provides further evidence for the relevance of non-additive effects in fitness-related traits, such as male fertility. In addition, these findings may point out new strategies for improving service sire fertility in dairy cattle via marker-assisted selection.

A polymorphism in the insulin-like growth factor 1 gene is associated with postpartum resumption of ovarian cyclicity in Holstein-Friesian cows under grazing conditions.

BACKGROUND: Insulin-like growth factor 1 (IGF-1) gene is considered as a promising candidate for the identification of polymorphisms affecting cattle performance. The objectives of the current study were to determine the association of the single nucleotide polymorphism (SNP) IGF-1/SnaBI with fertility, milk production and body condition traits in Holstein-Friesian dairy cows under grazing conditions. METHODS: Seventy multiparous cows from a commercial herd were genotyped for the SNP IGF-1/SnaBI. Fertility measures evaluated were: interval to commencement of luteal activity (CLA), calving to first service (CFS) and calving to conception (CC) intervals. Milk production and body condition score were also evaluated. The study period extended from 3 wk before calving to the fourth month of lactation. RESULTS AND DISCUSSION: Frequencies of the SNP IGF-1/SnaBI alleles A and B were 0.59 and 0.41, respectively. Genotype frequencies were 0.31, 0.54 and 0.14 for AA, AB and BB, respectively. Cows with the AA genotype presented an early CLA and were more likely to resume ovarian cyclicity in the early postpartum than AB and BB ones. No effect of the SNP IGF-1/SnaBI genotype was evidenced on body condition change over the experimental period, suggesting that energy balance is not responsible for the outcome of postpartum ovarian resumption in this study. Traditional fertility measures were not affected by the SNP IGF-1/SnaBI. CONCLUSION: To our knowledge this is the first report describing an association of the SNP IGF-1/SnaBI with an endocrine fertility measure like CLA in cattle. Results herein remark the important role of the IGF-1gene in the fertility of dairy cows on early lactation and make the SNP IGF-1/SnaBI an interesting candidate marker for genetic improvement of fertility in dairy cattle.

Genomic changes of Chagas disease vector, South America.

We analyzed the main karyologic changes that have occurred during the dispersion of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4-7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments.

Chromosome homogeneity in populations of Triatoma brasiliensis Neiva 1911 (Hemiptera - Reduviidae - Triatominae)

Têm-se reportado a ocorrência de quatro padröes cromáticos e diferentes padröes morfológicos, genéticos e ecológicos de Triatoma brasiliensis no semi-árido nordestino do Brasil, regiäo onde é o mais importante vetor da doença de Chagas. Para verificar diferenças citogenéticas nessas populaçöes, foram analisados seus cariótipos e o comportamento cromossomial durante o processo meiótico em exemplares machos. Observou-se que o T. brasiliensis mostra características cromossômicas distintas e específicas entre as quatro populaçöes, diferindo daquelas observadas em outras espécies de triatomíneos. No entanto, diferenças citogenéticas näo foram observadas entre as quatro populaçöes de T. brasiliensis, o que poderia indicar que as referidas populaçöes ainda se encontram em uma etapa inicial do processo de diferenciaçäo, ainda näo envolvendo a organizaçäo cromossomial.

Chromosome number in the Triatominae (Hemiptera-Reduviidae): a review

The chromosome numbers of 46 out of the 122 currently recognized species of Triatominae (Hemiptera, Reduviidae) are summarized. We present the number of autosomes, the sex mechanism and the first reference for each karyotype.