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One of the limitations of implementing animal breeding programs in small-scale or extensive production systems is the lack of production records and genealogical records. In this context, molecular markers could help to gain information for the breeding program. This study addresses the inclusion of molecular data into traditional genetic evaluation models as a random effect by molecular pedigree reconstruction and as a fixed effect by Bayesian clustering. The methods were tested for lactation curve traits in 14 dairy goat herds with incomplete phenotypic data and pedigree information. The results showed an increment of 37.3% of the relationships regarding the originals with MOLCOAN and clustering into five genetic groups. Data leads to estimating additive variance, error variance, and heritability with four different models, including pedigree and molecular information. Deviance Information Criterion (DIC) values demonstrate a greater fitting of the models that include molecular information either as fixed (genetic clusters) or as random (molecular matrix) effects. The molecular information of simple markers can complement genetic improvement strategies in populations with little information.

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The long 19th century was a period of many developments and technical innovations in agriculture and animal biology, during which actors sought to incorporate new practices in light of new information. By the middle of the century, however, while heredity steadily became the dominant concept in animal husbandry, some policies related to livestock improvement in Brazil seemed to have been tailored following a climate-deterministic concept established in the mid-18th century by the French naturalist Georges-Louis Leclerc, the Comte de Buffon. His theory of animal degeneration posited, among other things, the necessity of recurrent crossbreeding to preserve animal species living in nonnative environments from climate-induced degeneration. Although largely discredited by the early 19th century, the teachings of the French naturalist seem to have found supporters in a Brazilian program to modernize national agriculture through the application of the natural sciences. Herein I examine the revival of Buffon's theories in that government-sponsored program to improve animal husbandry and breeding techniques, including actual applications of this theory in the real world. Ultimately, I argue that Buffon's theory of degeneration was used to tailor public policies and funding for the improvement of domesticated animals in Brazil between 1856 and 1860.

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The study was conducted with the objective of estimating genetic and phenotypic parameters for tick (CRM) and Babesia bigemina (IBBi), Babesia bovis (IBBo), and Anaplasma marginale (IAM) burden in Angus female breed in Brazil. The sample group was composed of Angus females raised in herds located in a region of endemic instability for cattle tick fever in the state of Rio Grande Sul (RS), Brazil. The variance components were estimated using Bayesian inference and Gibbs sampling algorithm, considering a multi-trait animal model. Heritability estimates showed values of low magnitude, ranging from 0.03 (IBBo) to 0.16 (CRM), while repeatability estimates ranged between 0.07 (IBBo) and 0.21 (CRM). Regarding the genetic correlation estimates, the values showed low (-0.01 for IBBo × IAM) to moderate (0.55 between IBBi × IAM) magnitudes. The results indicate that it is possible to use tick count and hemoparasite infection levels as selection criteria, with small genetic gains.

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Community-based breeding programs (CBBPs) have shown, at pilot scale, to be effective and beneficial in achieving genetic progress and in improving livelihoods of smallholder communities. In Ethiopia 134 sheep and goat CBBPs were operational producing their own improved rams and bucks. Based on experience the implementation of further programs is possible with appropriate private and public support. A different challenge is the efficient dissemination of the improved genetics produced in current CBBPs to create population-wide economic impact. We present a framework applied to the Ethiopian Washera sheep breed to meet this challenge. We propose the establishment of a genetic improvement structure that supports a meat commercialization model based on the integration of community-based breeding program cooperatives, client communities and complementary services such as fattening enterprises. We calculated that the recently established 28 community-based breeding programs in the Washera breeding tract can provide genetically improved rams to 22% of the four million head. To reach the whole population 152 additional CBBPs are needed. We simulated the genetic improvements obtainable in the current 28 CBBPs assuming realized genetic progress in CBBPs of a similar breed and calculated the expected additional lamb carcass meat production after 10 years of selection to be 7 tons and the accumulated discounted benefit 327 thousand USD. These benefits could be increased if the CBBPs are linked to client communities by providing them with improved rams: additional meat production would be 138 tons with a value of 3,088 thousand USD. The total meat production of the existing Washera CBBPs was calculated at 152 tons and the joint meat production of CBBPs if integrated with client communities would be 3,495 tons. A full integration model, which includes enterprises purchasing lambs for fattening, can produce up to 4,255 tons of meat. We conclude that Washera CBBPs cooperatives can benefit from a higher level of organization to produce population-wide genetic improvement and economic benefits. Unlike in the dairy and chicken industries, for low input sheep and goat smallholder systems the proposed commercialization model puts breeder cooperatives at the center of the operation. Cooperatives need to be capacitated and supported to become fully functional business ventures.

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A new frame score system was developed for Nellore cattle, based upon ideal slaughter weights to achieve desired degrees of carcass fat cover. Data consisting of 688 complete records including sex, age, weight, hip height, and subcutaneous fat on growing Nellore cattle (190 males and 498 females) were obtained from the National Association of Breeders and Researchers (ANCP), Ribeirão Preto - SP, Brazil. Weight data were regressed on sex, age, hip height, and fat cover as covariates. Age was then fixed at 550 days and fat cover was set to 6 mm, and new equations for frame scores (1 to 11) in Nellore cattle were developed: FrameNellore (males) = -42.43 + 0.04919 × Age + 0.3368 × Height - 0.0003369 × Age × Height and FrameNellore (females) = -41.76 + 0.04919 × Age + 0.3368 × Height - 0.0003369 × Age × Height (Age and Height in days and cm, respectively). The Nellore equations resulted in average frame of 5.3, ranging from 2.3 to 7.7. Values were similar for males (5.4) and females (5.3). By contrast, previous equations gave higher values, that were very different between males and females. The new Nellore frame scores appear reasonable, particularly regarding body composition.(AU)

Um novo sistema de escore para estrutura corporal foi desenvolvido para bovinos Nelore, baseado em pesos de abate ideais para atingir os graus desejados de cobertura de gordura da carcaça. Dados de 688 registros completos incluindo sexo, idade, peso, altura do quadril e gordura subcutânea de bovinos Nelore em crescimento (190 machos e 498 fêmeas) foram obtidos da Associação Nacional de Criadores e Pesquisadores (ANCP), Ribeirão Preto - SP, Brasil. Os dados de peso foram regredidos por sexo, idade, altura do quadril e cobertura de gordura como covariáveis. A idade foi então fixada em 550 dias e a cobertura de gordura foi fixada em 6 mm, e novas equações para escores de estrutura corporal (1 a 11) em bovinos Nelore foram desenvolvidas: FrameNelore (machos) = -42,43 + 0,04919 × Idade + 0,3368 × Altura - 0,0003369 × Idade × Altura e FrameNellore (fêmeas) = -41,76 + 0,04919 × Idade + 0,3368 × Altura - 0,0003369 × Idade × Altura (Idade e Altura em dias e cm, respectivamente). As equações de Nelore resultaram em estrutura corporal médio de 5,3, variando de 2,3 a 7,7. Os valores foram semelhantes para machos (5,4) e fêmeas (5,3). Por outro lado, as equações anteriores deram valores mais altos, que eram muito diferentes entre machos e fêmeas. As novas pontuações de estruturacorporal no Nelore parecem razoáveis, principalmente em relação à composição corporal.(AU)

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Backfat is an important trait in pork production, and it has been included in the breeding objectives of genetic companies for decades. Although adipose tissue is a good energy storage, excessive fat results in reduced efficiency and economical losses. A large QTL for backfat thickness on chromosome 5 is still segregating in different commercial pig breeds. We fine mapped this QTL region using a genome-wide association analysis (GWAS) with 133,358 genotyped animals from five commercial populations (Landrace, Pietrain, Large White, Synthetic, and Duroc) imputed to the porcine 660K SNP chip. The lead SNP was located at 5:66103958 (G/A) within the third intron of the CCND2 gene, with the G allele associated with more backfat, while the A allele is associated with less backfat. We further phased the QTL region to discover a core haplotype of five SNPs associated with low backfat across three breeds. Linkage disequilibrium analysis using whole-genome sequence data revealed three candidate causal variants within intronic regions and downstream of the CCND2 gene, including the lead SNP. We evaluated the association of the lead SNP with the expression of the genes in the QTL region (including CCND2) in a large cohort of 100 crossbred samples, sequenced in four different tissues (lung, spleen, liver, muscle). Results show that the A allele increases the expression of CCND2 in an additive way in three out of four tissues. Our findings indicate that the causal variant for this QTL region is a regulatory variant within the third intron of the CCND2 gene affecting the expression of CCND2.

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The Blanco Orejinegro (BON) is a Colombian creole cattle breed that is not genetically well characterized for growth traits. The aim of this work was to estimate genetic parameters for birth weight (BW), weaning weight (WW), yearling weight (YW), daily weight gain between birth and weaning (DWG), time to reach 120 kg of live weight (T120), and time to reach 60% of adult weight (T60%), and establish the selection criteria for growth traits in the BON population of Colombia. Genealogical and phenotypic information for BW, WW, YW, DWG, T120, and T60% traits of BON animals from 14 Colombian herds were used. These traits were analyzed with the AIREML method in a uni- and bi-trait animal model including the maternal effect for BW, WW, DWG, and T120. The direct heritability estimates values were 0.22 ± 0.059 (BW), 0.20 ± 0.057 (WW), 0.20 ± 0.153 (YW), 0.17 ± 0.07 (DWG), 0.26 (T120), and 0.44 ± 0.03 (T60%). The maternal heritability estimates values were 0.14 ± 0.040 (BW), 0.15 ± 0.039 (WW), 0.25 ± 0.06 (DWG), and 0.16 (T120). The direct genetic correlations were high ( >|0.60|) among all the traits, except between T60% with BW, WW, YW, and DWG (ranged from - 0.02 to - 0.51), all in a favorable direction. The results showed that there is genetic variation in the growth traits associated with the additive genetic effect, and they might respond to selection processes. Furthermore, genetic gains would improve through selection, especially for YW and T60% when WW is used as criterion.

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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.

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The objective was to evaluate the existence of heterogeneity of variances and its impact on the genetic evaluation of ponderal performance in sires of the Nellore breed. We used records of adjusted body weights at 210 (W210), 365 (W365), and 450 (W450) days of age. Both W365 and W450 were combined by principal component analyses using the first component (PC). Average daily gain (ADG) was obtained by difference between W450 and W210. The classes of standard deviations (SD) for W210, PC, and ADG were obtained by the standardization of means of herd-year means subclasses, with positive values composing the high SD and values equal and less than zero composing the SD. The model included the fixed effects of contemporary group and age at calving as a covariate, random genetic additive, and maternal genetic (except for PC) effects, and the permanent maternal environment. Variance components were obtained by Gibbs sampling. Posterior means of heritability in analyses without considering heterogeneity of variances ranged from 0.15±0.01 to 0.31±0.01. Posterior means of genetic correlations between the two classes of SD for W210, PC, and ADG were equal to 0.85±0.04, 0.83±0.03, and 0.71±0.08, respectively. Spearman correlation to breeding values of sires for ADG as the selection intensity increased in them, and the correlations between breeding values in general analyses were more correlated with those predicted in the high DP. Therefore, when there is a higher selection intensity on the sires only for the ADG criterion, there is a significant presence of the heterogeneity of variances and impact on the genetic evaluation of the sires. Thus, for ADG, the predictions of breeding values obtained by the genetic evaluation model in which the heterogeneity of variances are not considered are more weighted by the class of greater heterogeneity.(AU)

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The objective of this work is to estimate genetic parameters and breeding values to improve embryo and oocyte production, using repeatability and random regression models (RRM) for Gir dairy cattle. We used 11,398 records of ovum pick-up from 1,747 dairy Gir donors and evaluated sixteen different models: the traditional repeatability model and fifteen RRM, each of which considered a different combination of Legendre polynomial regressors to describe the additive genetic and permanent environment effects. The 4G1P model (four regressors for the genetic effect and one regressor for the permanent environment effect) is the most suitable model to analyze the number of viable and total oocytes, while the 3G1P is the best model to analyze the number of cleaved and viable embryos, according to the values of the Akaike information criterion (AIC) and the Bayesian information criterion (BIC). The heritability estimated with the RRM was higher than that estimated with the repeatability model. The high repeatability reported for oocyte and embryo count traits indicates that donors, which had high oocyte and embryo counts in the first ovum pick-up, should maintain this result in the next ovum pick-up. Genetic correlations between adjacent ages were high and positive, while genetic correlations between extreme ages were weak. We observed a reranking of the top sires and females (heifers and cows) over the period evaluated. The reliability of the estimated breeding values by RRM showed changes across age, and the expected genetic gains by RRM are larger. This shows that RRM is most suitable alternative for the evaluation and selection of oocyte and embryo count traits.(AU)

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A implantação de programas de melhoramento genéticos bem delineados permite ganhos financeiros por meio da maximização de lucros através da geração de animais mais produtivos. Esse resultado é alcançado através de controle sistemático sobre a produção, proporcionando ganhos por geração, maior facilidade de manejo e otimização do espaço produtivo. É evidente o impacto dos programas desenvolvidos em espécies piscícolas, porém, espera-se maior expansão das ferramentas de melhoramento genético, principalmente em espécies nativas como o tambaqui, pintado e chácara, tornando indispensáveis mais estudos para o aperfeiçoamento e difusão de tais técnicas, considerando o grande potencial brasileiro para a produção aquícola.

The implementation of well-designed genetic improvement programs allows financial gains by maximizing profits through the generation of more productive animals. This result is achieved through systematic control over production, providing gains per generation, greater ease of handling and optimization of production space. The impact of the programs developed in fish species is evident, however, a greater expansion of genetic improvement tools is expected, especially in native species such as tambaqui, painted and farm, making more studies indispensable for the improvement and dissemination of such techniques, considering the great Brazilian potential for aquaculture production.

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Covariance components were estimated for growth traits (BW, birth weight; WW, weaning weight; YW, yearling weight), visual scores (BQ, breed quality; CS, conformation; MS, muscling; NS, navel; PS, finishing precocity), hip height (HH), and carcass traits (BF, backfat thickness; LMA, longissimus muscle area) measured at yearling. Genetic gains were obtained and validation models on direct and maternal effects for BW and WW were fitted. Genetic correlations of growth traits with CS, PS, MS, and HH ranged from 0.20 ± 0.01 to 0.94 ± 0.01 and were positive and low with NS (0.11 ± 0.01 to 0.20 ± 0.01) and favorable with BQ (0.14 ± 0.02 to 0.37 ± 0.02). Null to moderate genetic correlations were obtained between growth and carcass traits. Genetic gains were positive and significant, except for BW. An increase of 0.76 and 0.72 kg is expected for BW and WW, respectively, per unit increase in estimated breeding value (EBV) for direct effect and an additional 0.74 and 1.43, respectively, kg per unit increase in EBV for the maternal effect. Monitoring genetic gains for HH and NS is relevant to maintain an adequate body size and a navel morphological correction, if necessary. Simultaneous selection for growth, morphological, and carcass traits in line with improve maternal performance is a feasible strategy to increase herd productivity.

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The use of molecular markers to identify desirable genes in animal production is known as marker-assisted selection. The traditional genetic evaluation model uses the BLUP methodology; when genetic markers are included in the evaluation model, the methodology is known as M-BLUP. In contrast, random regression models (RRM), unlike the models based on production at 305 days, consider factors that change for each animal from one test to another. The objective of this study was to compare variance components, genetic parameters and breeding values for milk production, protein percentage and somatic cell score in Colombian Holstein cattle using BLUP, M-BLUP and RRM. For the estimation of genetic parameters and values, 2003 lactations corresponding to 1417 cows in 55 herds were used, and effects of the order of delivery, herd, and contemporary group were included. The three traits presented greater heritability under the MBLUP model: 0.44 for protein percentage, 0.27 for milk production and 0.28 for somatic cell score. This was because the genetic variance was greater when M-BLUP was used, which allowed a greater accuracy of the breeding value estimation in the three traits. Therefore, the model that includes information on molecular markers is more suitable for genetic evaluation in Colombian Holstein cattle.(AU)

O uso de marcadores moleculares para identificar genes desejáveis na produção animal é conhecido como seleção assistida por marcadores. O modelo tradicional de avaliação genética utiliza a metodologia BLUP, e quando os marcadores genéticos são incluídos no modelo de avaliação, a metodologia é conhecida como M-BLUP. Por outro lado, os modelos de regressão aleatória (RRM), ao contrário dos modelos baseados em produções a 305 dias, consideram fatores que mudam para cada indivíduo de um controle para outro. O objetivo deste estudo foi comparar componentes de variância, parâmetros e valores genéticos para produção de leite, percentagem de proteína e escore de células somáticas em gado holandês de Colômbia utilizando BLUP, M-BLUP e RRM. Para a estimativa de parâmetros e valores genéticos, foram utilizadas 2.003 lactações correspondentes a 1.417 vacas de 55 rebanhos e efeitos da ordem de parto, rebanho e grupo contemporâneo. Os três traços apresentaram maior hereditariedade no modelo MBLUP, 0,44 para percentagem de proteína, 0,27 para produção de leite e 0,28 para escore de células somáticas. Isso por causa da variância genética foi maior quando o M-BLUP foi utilizado, o que permitiu estimar maior precisão do valor genético nos três traços, portanto, o modelo que inclui informações sobre marcadores moleculares é mais adequado para avaliação genética em gado holandês colombiano.(AU)

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Dairy farming in the state of Roraima, Brazil, is majorly supported by Holstein x Gir crossbred cattle, which are more adapted to the tropical climate and traditional production systems. However, there is a need to adapt the genetic groups to production systems and raise awareness of the importance of using visual phenotypic assessments as an auxiliary tool in obtaining and selecting animals. This study proposes to identify the frequency and characterize the phenotype of the » Hol + ¾ Gir; ⅜ Hol + ⅝ Gir; ½ Hol + ½ Gir; ⅝Hol + ⅜ Gir; ¾ Hol + » Gir; and ⅞ Hol + ⅛ Gir genetic groups of the Girolando breed in herds in the state of Roraima. Data were obtained from visual morphological evaluations to identify the genetic groups and characterize the phenotype of the animals from August 2016 to February 2017. According to the evaluations, the frequency distribution of the genetic groups was as follows: 210 (21.26%) of the » Hol + ¾ Gir group; 145 (14.68%) of the ⅜ Hol + ⅝ Gir group; 249 (25.20%) of the ½ Hol ½ Gir group; 166 (16.80%) of the ⅝ Hol + ⅜ Gir group; 126 (12.75%) of the ¾ Hol + » Gir group; and 92 (9.3%) of the ⅞ Hol + ⅛ Gir group. In the phenotypic evaluations, statistically significant differences (p<0.05) were detected in the ¾ Hol + » Gir genetic group for overall appearance (OA); in ⅝ Hol + ⅜ Gir and ⅞ Hol + ⅛ Gir for Body Capacity (BC); in ½ Hol + ½ Gir for Dairy Traits (DT); and in ¾ Hol + » Gir and ⅞ Hol + ⅛ Gir for Reproductive System and Feet-Leg Structure (RS/FL). The ½ Hol + ½ Gir genetic group was superior for BC, DT and RS/FL, being best classified as to the Girolando breed type and revealing better characterization and uniformity per selection process.(AU)

A pecuária leiteira do Estado de Roraima é sustentada por bovinos mestiços Holandês x Gir, animais mais adaptados ao clima tropical e aos sistemas de produção tradicionais. No entanto, existe a necessidade de adequação dos grupos genéticos aos sistemas de produção e de sensibilizar quanto à importância do uso de avaliações visuais fenotípicas como ferramenta de auxilio na obtenção e seleção dos animais. Os objetivos da pesquisa consistiram em identificar a frequência e caracterizar o fenótipo dos grupos genéticos » Hol + ¾ Gir, ⅜ Hol + ⅝ Gir, ½ Hol + ½ Gir, ⅝ Hol + ⅜ Gir, ¾ Hol + » Gir e ⅞ Hol + ⅛ Gir da raça Girolando nos rebanhos do Estado de Roraima. Os dados foram obtidos a partir de avaliações visuais morfológicas para identificar os grupos genéticos e caracterizar o fenótipo dos animais no período de agosto de 2016 a fevereiro de 2017. A distribuição da frequência dos grupos genéticos de acordo com as avaliações foi de: 210 (21,26%) do grupo » Hol + ¾ Gir; 145 (14,68%) do grupo ⅜ Hol + ⅝ Gir; 249 (25,20%) do grupo ½ Hol ½ Gir; 166 (16,80%) do grupo ⅝ Hol + ⅜ Gir; 126 (12,75%) do grupo ¾ Hol + » Gir e 92 (9,3%) do grupo ⅞ Hol + ⅛ Gir. Nas avaliações fenotípicas foram observadas diferenças estaticamente significativas (p<0,05) no grupo genético ¾ Hol + » Gir para Aparência Geral (AG), nos grupos genéticos ⅝ Hol + ⅜ Gir e ⅞ Hol + ⅛ Gir para Capacidade Corporal (CC), nogrupo ½ Hol + ½ Gir para Características Leiteiras (CL) e nos grupos ¾ Hol + » Gir e ⅞ Hol + ⅛ Gir para Aparelho Reprodutor e Aprumos (AR/A). O grupo genético ½ Hol + ½ Gir foi superior nas características Capacidade Corporal (CC), Características Leiteiras (CL) e Aparelho Reprodutor e Aprumos (AR/A), sendo melhores classificados quanto ao tipo da raça Girolando demonstrando melhor caracterização e uniformização por processo seletivo.(AU)

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The goal of this study was to compare the predictive performance of artificial neural networks (ANNs) with Bayesian ridge regression, Bayesian Lasso, Bayes A, Bayes B and Bayes Cπ in estimating genomic breeding values for meat tenderness in Nellore cattle. The animals were genotyped with the Illumina Bovine HD Bead Chip (HD, 777K from 90 samples) and the GeneSeek Genomic Profiler (GGP Indicus HD, 77K from 485 samples). The quality control for the genotypes was applied on each Chip and comprised removal of SNPs located on non-autosomal chromosomes, with minor allele frequency <5%, deviation from HWE (p < 10-6 ), and with linkage disequilibrium >0.8. The FImpute program was used for genotype imputation. Pedigree-based analyses indicated that meat tenderness is moderately heritable (0.35), indicating that it can be improved by direct selection. Prediction accuracies were very similar across the Bayesian regression models, ranging from 0.20 (Bayes A) to 0.22 (Bayes B) and 0.14 (Bayes Cπ) to 0.19 (Bayes A) for the additive and dominance effects, respectively. ANN achieved the highest accuracy (0.33) of genomic prediction of genetic merit. Even though deep neural networks are recognized to deliver more accurate predictions, in our study ANN with one single hidden layer, 105 neurons and rectified linear unit (ReLU) activation function was sufficient to increase the prediction of genetic merit for meat tenderness. These results indicate that an ANN with relatively simple architecture can provide superior genomic predictions for meat tenderness in Nellore cattle.

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Dairy farming in the state of Roraima, Brazil, is majorly supported by Holstein x Gir crossbred cattle, which are more adapted to the tropical climate and traditional production systems. However, there is a need to adapt the genetic groups to production systems and raise awareness of the importance of using visual phenotypic assessments as an auxiliary tool in obtaining and selecting animals. This study proposes to identify the frequency and characterize the phenotype of the » Hol + ¾ Gir; ⅜ Hol + ⅝ Gir; ½ Hol + ½ Gir; ⅝Hol + ⅜ Gir; ¾ Hol + » Gir; and ⅞ Hol + ⅛ Gir genetic groups of the Girolando breed in herds in the state of Roraima. Data were obtained from visual morphological evaluations to identify the genetic groups and characterize the phenotype of the animals from August 2016 to February 2017. According to the evaluations, the frequency distribution of the genetic groups was as follows: 210 (21.26%) of the » Hol + ¾ Gir group; 145 (14.68%) of the ⅜ Hol + ⅝ Gir group; 249 (25.20%) of the ½ Hol ½ Gir group; 166 (16.80%) of the ⅝ Hol + ⅜ Gir group; 126 (12.75%) of the ¾ Hol + » Gir group; and 92 (9.3%) of the ⅞ Hol + ⅛ Gir group. In the phenotypic evaluations, statistically significant differences (p<0.05) were detected in the ¾ Hol + » Gir genetic group for overall appearance (OA); in ⅝ Hol + ⅜ Gir and ⅞ Hol + ⅛ Gir for Body Capacity (BC); in ½ Hol + ½ Gir for Dairy Traits (DT); and in ¾ Hol + » Gir and ⅞ Hol + ⅛ Gir for Reproductive System and Feet-Leg Structure (RS/FL). The ½ Hol + ½ Gir genetic group was superior for BC, DT and RS/FL, being best classified as to the Girolando breed type and revealing better characterization and uniformity per selection process.

A pecuária leiteira do Estado de Roraima é sustentada por bovinos mestiços Holandês x Gir, animais mais adaptados ao clima tropical e aos sistemas de produção tradicionais. No entanto, existe a necessidade de adequação dos grupos genéticos aos sistemas de produção e de sensibilizar quanto à importância do uso de avaliações visuais fenotípicas como ferramenta de auxilio na obtenção e seleção dos animais. Os objetivos da pesquisa consistiram em identificar a frequência e caracterizar o fenótipo dos grupos genéticos » Hol + ¾ Gir, ⅜ Hol + ⅝ Gir, ½ Hol + ½ Gir, ⅝ Hol + ⅜ Gir, ¾ Hol + » Gir e ⅞ Hol + ⅛ Gir da raça Girolando nos rebanhos do Estado de Roraima. Os dados foram obtidos a partir de avaliações visuais morfológicas para identificar os grupos genéticos e caracterizar o fenótipo dos animais no período de agosto de 2016 a fevereiro de 2017. A distribuição da frequência dos grupos genéticos de acordo com as avaliações foi de: 210 (21,26%) do grupo » Hol + ¾ Gir; 145 (14,68%) do grupo ⅜ Hol + ⅝ Gir; 249 (25,20%) do grupo ½ Hol ½ Gir; 166 (16,80%) do grupo ⅝ Hol + ⅜ Gir; 126 (12,75%) do grupo ¾ Hol + » Gir e 92 (9,3%) do grupo ⅞ Hol + ⅛ Gir. Nas avaliações fenotípicas foram observadas diferenças estaticamente significativas (p<0,05) no grupo genético ¾ Hol + » Gir para Aparência Geral (AG), nos grupos genéticos ⅝ Hol + ⅜ Gir e ⅞ Hol + ⅛ Gir para Capacidade Corporal (CC), nogrupo ½ Hol + ½ Gir para Características Leiteiras (CL) e nos grupos ¾ Hol + » Gir e ⅞ Hol + ⅛ Gir para Aparelho Reprodutor e Aprumos (AR/A). O grupo genético ½ Hol + ½ Gir foi superior nas características Capacidade Corporal (CC), Características Leiteiras (CL) e Aparelho Reprodutor e Aprumos (AR/A), sendo melhores classificados quanto ao tipo da raça Girolando demonstrando melhor caracterização e uniformização por processo seletivo.

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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

RESUMO

Males of Proechimys guyannensis, a rodent living in the Amazon rainforest are studied in biomedical research because of their antiepileptogenic mechanism. Females are usually taken from experimental designs, because of limited data of this sex. This study aimed to characterize the estrous cycle to include females together with males in research in a more balanced approach. The estrous cycle of P. guyannensis based through exfoliative cytology, determination of the vaginal occlusion membrane state, and hormonal analysis. In this study, cytological analyses of vaginal smears were performed for three months, three times a day. The observed length of the estrous cycle was 247 ± 81 h (mean ± SD) with a reproductive phase of 27.08 ± 17.39 h (estrus stage). We observed a frequent presence of both the open and closed states of the vaginal membrane in the estrus stage (fertile period) although only the open stage is a prerequisite for successful copulation. High levels of progesterone and estradiol were detected in proestrus. Levels of follicle-stimulating hormone peaked at the estrus stage. These data will establish the parameters and subsidies to set the grounds for future research either for investigating the biology of this species or to use P. guyannensis in research that previously excluded females. Information regarding female Proechimys is relevant to not only describe the species but also explain the interaction between sex hormones and physiological responses. Moreover, the present results will enhance rigor and reproducibility in preclinical studies. In conclusion, P. guyannensis reproductive cycles can occur spontaneously and cyclically independent of mating stimulation and the high levels of FSH in the estrus stage, suggest that ovulation occurs in the late phase of the estrus.