•Measure stayability to each calving is useful to get earlier indicators of longevity.•Heritability estimates had a similar trend, being higher for intermediate calvings.•Selection to stayability to ...second calving result in genetic gain in later calvings.•Cubic random regression models can be used for stayability to consecutive calvings.
The trait stayability is a way of assessing productive life and has been measured late in the cow's life. Measuring the stayability to each calving is a strategy that can be implemented to obtain earlier indicators of longevity. Thus, the objective with this study was the estimation of genetic parameters for stayability to consecutive calvings for Angus/Brangus and Hereford/Braford cattle breeds. By using random regression animal models, different orders of Legendre orthogonal polynomials were compared. According to DIC, the model with cubic Legendre polynomials (4 coefficients) was the most appropriate. Heritability estimates ranged from 0.05 to 0.08 for and had a similar trend for both breeds, being higher for stayability at intermediate calvings (fourth to sixth). Genetic correlation estimates were from 0.47 to 0.87 and 0.63 to 0.93 for Angus/Brangus and Hereford/Braford, respectively, and were higher for stayability between closer calvings. The estimates observed for genetic correlations indicate that the genetic control of stayability to each calving is performed by the same group of genes, at least partially. For this reason, the selection to increase the probability of stayability to second calving can result in a moderate genetic gain in subsequent calvings. Cubic random regression models can be used for the genetic evaluation of the stayability to consecutive calvings in beef cattle.
Stayability (STAY) is a way to evaluate the productive longevity of females. Measuring the STAY at each cow calving allows earlier indicators of longevity to be obtained. Our objective with this ...study was to verify the association between STAY and consecutive calvings and traits potentially used as selection criteria in beef cattle, such as age at first calving (AFC), days to calving (DC), weaning weight (WW), and yearling weight (YW). Data from the Nelore, Angus/Brangus, and Hereford/Braford breeds were used. The estimation of variance components and subsequent prediction of breeding values were performed for all traits. The estimated breeding values (EBV) were used to analyse the association between STAY and the other traits. The Pearson's correlation estimated between the EBV for the intercept coefficient for STAY to consecutive calvings and those of AFC, DC, WW (direct and maternal effects), and YW was favourable and of low magnitude (<0.25) depending on the breed studied. The influence of the genetic merit of AFC on the chance of selection for STAY was favourable and relevant regardless of the intensity of selection and breed. DC and WW (maternal effect) traits were favourably influenced by the chance of selection for STAY, irrespective of breed. The WW (direct effect) did not affect the chance of selection for STAY for the Nelore and Hereford/Braford breeds and negatively influenced, but to a small extent, the Angus/Brangus breed. For YW, an increase in genetic merit affected the chances of selection for STAY, depending on the breed and selection intensity evaluated. The influence of the genetic merit for AFC, DC, and WW (maternal effect) on the chance of selection for STAY to consecutive calvings was favourable and relevant regardless of the selection intensity scenario evaluated. The WW (direct effect) did not influence the chance of selection for STAY. For the scenario with high selection intensity, the selection for YW favourably influenced the chance of selection for STAY in Angus/Brangus and Hereford/Braford breeds but not in Nelore.
•In Holstein cows, extreme milk yields are associated with a reduction in longevity.•Better udders and feet and legs conformation are associated with a lower SCS.•It is possible to promote early ...genetic gains in the longevity by correlated traits.
Genetic associations were estimated between 305-day cumulative milk yield (MY305) and maximum somatic cell score (SCS) in the first lactation, stayability in the herd at 60 months of age (Stay60), and linear udder and feet and legs traits. First-lactation records of Holstein cows reared in intensive production systems in Brazil were used. The (co)variance components were estimated using a Bayesian approach. The heritability estimates were 0.24 ± 0.02, 0.08 ± 0.02 and 0.09 ± 0.03 for MY305, SCS and Stay60, respectively. The heritabilities of the linear traits ranged from 0.16 to 0.39 for udder traits and from 0.13 to 0.21 for feet and legs traits. Stay60 showed genetic correlations of -0.25 ± 0.12 with MY305, 0.11 ± 0.20 with SCS, 0.33 ± 0.16 with rear teat placement, and -0.47 ± 0.13 with a rear legs-side view. It is possible to promote early genetic gains in the longevity of animals by selecting for moderately correlated traits to obtain a good set of feet and legs, as well as well-positioned teats of medium length. Extreme milk yields are associated with a reduction in Stay60. SCS in the first lactation has practically no influence on Stay60. The maximum selection efficiency will be achieved by selecting directly by Stay60.
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.
The German Shepherd dog breed is the most popular breed globally and in Brazil. The study of the population structure through pedigree information is an essential tool to understand the history of ...the Brazilian German Shepherd dog breed. This study evaluated the status of genetic diversity and population structure of the Brazilian German Shepherd dog breed. The pedigree included a total of 77,938 animals born between 1970 and 2014. The average generation interval in this population was 3.91 years. Considering the reference population, 2,183 founders were identified. Approximately 3% of the genetic diversity of the current population (2010-2014) was lost, most of which was due to genetic drift. The effective population size was relatively small, and the pedigree showed bottlenecks indicating a loss of genetic diversity in this breed. These results indicated the need to adopt measures against the excessive increase in inbreeding and monitor effective population size to minimize genetic diversity loss.
RESUMO: A raça Pastor Alemão é uma das raças mais populares no mundo e no Brasil. O estudo da estrutura populacional por meio de informações de pedigree é uma ferramenta essencial para o entendimento da história dessa raça no Brasil. Objetivou-se com o estudo avaliar o status da diversidade genética e da estrutura populacional de cães da raça Pastor Alemão. O pedigree incluiu um total de 77.938 animais nascidos entre 1970 e 2014. O intervalo médio de geração nesta população foi de 3,91 anos. Considerando a população de referência, foram identificados 2.183 fundadores. Cerca de 3% da diversidade genética da população atual (2010-2014) foi perdida, a maior parte devido à deriva genética. O tamanho efetivo da população foi relativamente pequeno e o pedigree apresentou gargalos indicando uma perda de diversidade genética nesta raça. Esses resultados indicam a necessidade de adoção de medidas contra o aumento excessivo da endogamia e do monitoramento do tamanho efetivo da população para minimizar a perda de diversidade genética.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
6.
Currículo cultural Silva Júnior, Welington Santana; Ferrari Nunes, Mário Luiz
Movimento (Porto Alegre, Brazil),
04/2023, Letnik:
29
Journal Article
Recenzirano
Odprti dostop
Neste artigo, apresentamos o modo como o encaminhamento didático-metodológico do Currículo Cultural da Educação Física denominado ressignificação emerge nas aulas do componente e alguns de seus ...possíveis efeitos nos modos de subjetivação dos discentes. Por meio de uma autoetnografia, produzimos um relato de prática pedagógica, o qual analisamos com base no quadro teórico que ancora essa perspectiva curricular e nas noções de governamentalidade e contraconduta desenvolvidas por Michel Foucault. Notamos que a ressignificação desponta nas ações de resistência promovidas pelos discentes em relação aos modos de regulação das aulas e da prática corporal em estudo. Visto que essas resistências possibilitaram aos discentes elaborarem ações de contraconduta. Um processo que possibilitou outras conduções de si, do outro, assim como diferentes formas de ser, viver e pensar sobre a prática corporal em estudo, potencializando práticas de liberdade.
In beef cattle breeding programs, various selection criteria have been proposed and employed with the aim of improving traits related to carcass composition and the quality of the final product, ...meat. However, the importance of genotype by environment interaction (G×E) for such traits is still not well understood. Our objectives were: 1) to investigate the importance of G×E on ultrasound carcass traits, growth and visual scores and 2) to estimate the genetic correlation of ultrasound carcass traits with growth and visual scores taking into account the G×E in Hereford and Braford cattle. A multiple-trait reaction norm model was fitted to the field records of 37,948 animals. With the exception of postweaning average daily weight gain (ADG), the G×E can lead to important changes in the ranking of estimated breeding values of sires across environments for all traits. Thus, models that consider heterogeneity of genetic variances along an environmental gradient may be considered more appropriate for genetic evaluations of animals reared under conditions similar to the present study. Based on estimates of genetic correlation, the quality of visual scores or ADG as indicators of carcass quality assessed by ultrasonography is dependent on the production environment.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
We assessed variations in chest CT usage, radiation dose and image quality in COVID-19 pneumonia. Our study included all chest CT exams performed in 533 patients from 6 healthcare sites from ...Brazil. We recorded patients’ age, gender and body weight and the information number of CT exams per patient, scan parameters and radiation doses (volume CT dose index—CTDIvol and dose length product—DLP). Six radiologists assessed all chest CT exams for the type of pulmonary findings and classified CT appearance of COVID-19 pneumonia as typical, indeterminate, atypical or negative. In addition, each CT was assessed for diagnostic quality (optimal or suboptimal) and presence of artefacts. Artefacts were frequent (367/841), often related to respiratory motion (344/367 chest CT exams with artefacts) and resulted in suboptimal evaluation in mid-to-lower lungs (176/344) or the entire lung (31/344). There were substantial differences in CT usage, patient weight, CTDIvol and DLP across the participating sites.
The objective of the present study was to evaluate the effects of different selection practices on the environmental sensitivity of reproductive and growth traits in males and females of three ...Nellore selection lines control (NeC), selection (NeS), and traditional (NeT) lines. Moreover, genetic trends for the intercept and slope were estimated for each line, and the possible reranking of sires was examined. A total of 8,757 records of selection weight (SW), 3,331 records of scrotal circumference (SC), and 2,311 records of days to first calving (DFC) from Nellore cattle born between 1981 and 2017 were analyzed. (Co)variance components and genetic parameters of all traits were estimated using a reaction norm model with Gibbs sampler. In all cattle lines, the mean heritability of the studied traits ranged from 0.39 to 0.75 for SW in both males and females, from 0.46 to 0.68 for SC, and from 0.06 to 0.57 for DFC along with the environmental descriptor. In all cattle lines, the genetic correlation coefficients between the intercept and slope ranged from 0.03 to 0.81 for SW, from -0.14 to 0.39 for SC, and from -0.87 to -0.42 for DFC. Genetic trends for the slope and proportion of plastic genotypes indicated that the NeS line was more responsive to environmental changes, whereas the NeC and NeT lines tended to respond more modestly. Reranking of sires was observed for all traits, specifically in the NeC and NeT lines, because of the weak correlation between the opposite extreme environments. In the NeS line, reranking of sires was observed for DFC alone. Our results indicate that the effects of genotype-environment interaction are important and should be considered in genetic evaluations of Nellore cattle. Moreover, different selection practices affected the environmental sensitivity of the Nellore selection lines tested in this study.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
In this study, the use of Pinhão husk as a source of reinforcement material for development of edible films, where the Pinhão seed flour and bovine gelatin were used as matrices for the ...films. Mechanical properties, water vapor permeability, solubility and opacity, microstructure, and thermal degradation characterized the films produced. The films presented homogeneous and cohesive structures. Pinhão husk content positively affected film properties by increasing tensile strength (TS) and decreasing water vapor permeability (WVP), with Pinhão flour film formulations (5.0% Pinhão flour, 1.2% glycerol, and 0.4% Pinhão husk) and gelatin (5.0% gelatin, 2.0% glycerol, and 0.4% Pinhão husk) those that presented the best results (5.06 MPa for TS and 0.14 g.mm/kPa.h.m
2
for WVP) and (3.88 MPa for TS and 0.28 g.mm/kPa.h.m
2
for WVP), respectively The thermal degradation study revealed that the films are stable at temperatures below 150°C, losing only free water and volatile compounds of low molecular weight. Pinhão husk can reinforce films, making them suitable as biodegradable and edible packaging materials for eco‐friendly food products. This contributes to the circular economy, preserves biodiversity, and reduces plastic waste, offering promising sustainable packaging solutions.
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