Search

Background Various diagnostic tests are available to establish the primary aldosteronism (PA) diagnosis and to determine the disease laterality. Combined with the controversies in the literature, unawareness of guidelines and technical demands and high costs of some of these diagnostics, this could lead to significant differences in work-up strategies worldwide. Therefore, we investigated the work-up before surgery for PA in daily clinical practice within a multicenter study. Methods Patients who underwent unilateral adrenalectomy for PA within 16 centers in Europe, Canada, Australia and the USA between 2010 and 2016 were included. We did not exclude patients based on the performed diagnostic tests during work-up to make our data representative for current clinical practice. Adherence to the Endocrine Society Guideline and variables associated with not performing adrenal venous sampling (AVS) were analyzed. Results In total, 435 patients were eligible. An aldosterone-to-renin ratio, confirmatory test, computed tomography (CT), magnetic resonance imaging and AVS were performed in 82.9%, 32.9%, 86.9%, 17.0% and 65.3% of patients, respectively. A complete work-up, as recommended by the guideline, was performed in 13.1% of patients. Bilateral disease or normal adrenal anatomy on CT (OR 16.19; CI 3.50–74.99), smaller tumor size on CT (OR 0.06; CI 0.04–0.08) and presence of hypokalemia (OR 2.00; CI 1.19–3.32) were independently associated with performing AVS. Conclusions This study is the first to examine the daily clinical practice work-up of PA within a worldwide cohort of surgical patients. The results demonstrate significant variability in work-up strategies and low adherence to The Endocrine Society guideline.

Background: Malpositioned central venous access devices (CVADs) can lead to significant patient injury including central vein thrombosis and dysrhythmias. Intra-cavitary electrocardiography (IC ECG) has been recommended by peak professional bodies as an accurate alternative for bedside CVAD insertion, to reduce risk of malposition and allowing immediate use of the device. Our objective was to compare the effect of IC ECG on CVAD malposition compared to traditional institutional practice for CVAD placement. Methods: Randomised controlled trial of IC ECG CVAD insertion verses traditional CVAD insertion (surface landmark measurement with post insertion x ray). Patient recruitment was from December 2016 to July 2018. The setting was a 900-bed tertiary referral hospital based in South Western Sydney, Australia. Three hundred and forty-four adult patients requiring CVAD insertion for intravenous therapy, were enrolled and randomly allocated (1:1 ratio) to either IC-ECG (n = 172) or traditional (n = 172) CVAD insertion. Our primary outcome of interest was the rate of catheters not requiring repositioning after insertion (ready for use). Secondary outcomes were comparison of procedure time and cost. Results: Of the 172 patients allocated to the IC ECG method, 170 (99%) were ready for use immediately compared to 139 of the 172 (81%) in the traditional insertion group (difference, 95% confidence interval (CI): 18%, 11.9–24.1%). The total procedure time was mean 15 min (SD 8 min) for IC ECG and mean 36 min (SD 17 min) for traditional CVAD insertion (difference–19.9 min (95% CI–14.6 to −34.4). IC ECG guided CVAD insertion had a cost reduction of AUD $62.00 per procedure. Conclusions: Using IC-ECG resulted in nearly no requirement for post-insertion repositioning of CVADs resulting in savings in time and cost and virtually eliminating the need for radiographic confirmation. Trial registration: This trial is registered at the Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au). The registration number is ACTRN12620000919910. © The Author(s) 2022.

Older adults tend to focus on positive information over negative information; a phenomenon commonly referred to as the ‘positivity effect’. Socioemotional Selectivity Theory posits that this effect stems from age-related shifts in goals and relies heavily on the active suppression of negative information. The current study tested the hypothesis that inhibitory control is a key determinant of positivity biases in older adults using anti-saccade and recognition memory tasks. Results indicated a significant correlation between levels of inhibitory control and the positivity effect. These findings highlight the key role played by inhibitory control in determining positivity biases amongst older adults.

Bos taurus taurus and Bos taurus indicus cattle subspecies present different capabilities in coping with situations of elevated temperatures, the latter being more tolerant to heat stress. Thus, some breeding programs crossed these subspecies to produce a high producing yet heat-tolerant breed (Girolando). Nineteen Holstein (H100) and 19 Girolando cows [(½ Holstein × Gir (H50) and ¾ Holstein × Gir (H75)] with similar milk production were used in a six-day experiment to evaluate the consequences of heat stress due to shade deprivation on their physiological, blood and milk traits. Cows were exposed to a non-shaded environment between morning (06:00h; GMT -3:00) and evening milking (14:30h; GMT -3:00) with access to water ad libitum. Procedures were conducted before morning and evening milkings. Physiological parameters related to mechanisms of heat dissipation were measured, as well as the milk composition. Blood traits were evaluated. The temperature-humidity index (THI) was calculated. Statistical procedures included analysis of variance, correlation, and principal factors. THI was elevated during the trial and negatively impacted physiological, milk, and blood parameters in H100, H75, and H50. Alterations in physiology, milk stability, milk composition, and blood traits were more pronounced in H100. Holstein cows presented changes in physiological parameters in a more pronounced manner and in some milk and blood traits related to the reduced capability of this breed in dealing with elevated THI. The similarity in milk production levels excludes this parameter as a justification for differences in heat tolerance, with genetic composition being the main reason for these results. Made available in DSpace on 2021-11-25T12:04:23Z (GMT). No. of bitstreams: 1 Elevated-temperature-humidity.pdf: 761551 bytes, checksum: 0e2950a57ff402580f102316e5cd8df9 (MD5) Previous issue date: 2021

Made available in DSpace on 2017-11-20T23:31:34Z (GMT). No. of bitstreams: 1 Cnpgl2017RevBrasZootInfrared.pdf: 1742584 bytes, checksum: 140e37615fe7436aac110ed6a92a7b29 (MD5) Previous issue date: 2017-11-20

In order for autonomous vehicles to achieve life-long operation in outdoor environments, navigation systems must be able to cope with visual change---whether it's short term, such as variable lighting or weather conditions, or long term, such as different seasons. As a GPS is not always reliable, autonomous vehicles must be self sufficient with onboard sensors. This thesis examines the problem of localisation against a known map across extreme lighting and weather conditions using only a stereo camera as the primary sensor. The method presented departs from traditional techniques that blindly apply out-of-the-box interest-point detectors to all images of all places. This naive approach fails to take into account any prior knowledge that exists about the environment in which the robot is operating. Furthermore, the point-feature approach often fails when there are dramatic appearance changes, as associating low-level features such as corners or edges is extremely difficult and sometimes not possible. By leveraging knowledge of prior appearance, this thesis presents an unsupervised method for learning a set of distinctive and stable (i.e., stable under appearance changes) feature detectors that are unique to a specific place in the environment. In other words, we learn place-dependent feature detectors that enable vastly superior performance in terms of robustness in exchange for a reduced, but tolerable metric precision. By folding in a method for masking distracting objects in dynamic environments and examining a simple model for external illuminates, such as the sun, this thesis presents a robust localisation system that is able to achieve metric estimates from night-today or summer-to-winter conditions. Results are presented from various locations in the UK, including the Begbroke Science Park, Woodstock, Oxford, and central London.

The objective of this study was to compare physiological and thermographic responses to heat stress in three breeds of cattle. Fifteen animals of each of the Nelore, Pantaneiro and Curraleiro Pe-Duro breeds, of approximately two years of age, were evaluated. Heart and respiratory rates, rectal and surface temperature of animals as well as soil temperature were recorded at 8:30 and 15:30 on six days. Variance, correlation, principal factors and canonical analyses were carried out. There were significant differences in the rectal temperature, heart and respiratory rate between breeds (p < 0.001). Nelore and Pantaneiro breeds had the highest rectal temperatures and the lowest respiratory rate (p < 0.001). Breed was also significant for surface temperatures (p < 0.05) showing that this factor significantly affected the response of the animal to heat tolerance in different ways. The Curraleiro Pe-Duro breed had the lowest surface temperatures independent of the period evaluated, with fewer animals that suffered with the climatic conditions, so this may be considered the best adapted when heat challenged under the experimental conditions. Thermography data showed a good correlation with the physiological indexes, and body area, neck and rump were the main points.

Made available in DSpace on 2015-03-13T02:56:07Z (GMT). No. of bitstreams: 1 Georeferencedevaluationofgenetic....pdf: 652122 bytes, checksum: be8648626b3444d3ffec7da5d20fdd72 (MD5) Previous issue date: 2015-03-12

A identificação de parâmetros/ métricas associados à adaptação ambiental é uma das principais tendências e desafios da pecuária mundial. Desta forma, o objetivo deste trabalho foi avaliar as características de tolerância ao calor de bovinos da raça Nelore e Pantaneiro no ecossistema do Pantanal matogrossense no pico de calor da região. Estes animais foram mantidos por duas horas à sombra (8:00h às 10:00h) e em seguida uma hora ao sol (10:00h às 11:00h). Após a exposição foram analisados parâmetros de frequência cardíaca (FC), frequência respiratória (FR), temperatura retal (TR), temperatura superficial da costela (TSC), temperatura superficial do pescoço (TSP) e temperatura superficial da garupa (TSG). Também foram avaliados a taxa de sudação (TXS), comprimento e densidade de pelos e calculados o índice de tolerância ao calor (ITC). No período estudado, a temperatura ambiental variou de 29,0 a 40,0°C e a média para umidade relativa foi de 75%. O ambiente teve influência marcante sobre as variáveis fisiológicas, com exceção da FR. A TR e a TXS diferiram significativamente entre os grupos genéticos, sendo da raça Nelore mais elevada em relação à Pantaneira, mas todas dentro dos limites fisiológicos. A análise multivariada mostrou a importância de variáveis como taxa de sudação e comprimento de pelos para adaptação de bovinos na região. Apesar do Nelore vermelho estar separado dos outros dois grupos, foi possível concluir que ambas as raças analisadas apresentaram capacidade de adaptação e tolerância ao calor às condições climáticas do Pantanal e podem ser produzidas de modo sustentável na região.

Repetitive strain injury (RSI) is a syndrome in the upper extremities (hands, arms, shoulder and/or neck) and is characterized by sensations of pain, stiffness, fatigue, heat and cold, tingling, numbness, redness of the skin, cramps and loss of fine movement control, eventually leading to general disability. Usually pain, fatigue and stiffness, especially in the neck and shoulder region, are early symptoms, whereas functional loss and disability are mostly seen in advanced states. Initial, temporary episodes of pain and fatigue during repetitive tasks are defined as phase I severity. In phase II the pain has become more persistent and has generalized to other everyday movements. In phase III, pain and functional loss are continuous and unrelated to repetitious movements. Since symptoms primarily develop in people whose work involves repetitious movements during long shifts, RSI is considered a typical occupational disorder with overuse of upper extremity muscles as a common denominator, although excessive computer gaming has been known to cause RSI complaints as well (‘Nintendo arm’). Alternative terms are ‘occupational overuse syndrome’, ‘work-related upper extremity disorder’ (WRUED) and sometimes ‘focal dystonia’, although the latter term essentially refers to a different, neurological disorder. Specific and non-specific forms of RSI RSI complaints generally do not relate to any known biological disorder. Only in a minority of cases ( et al ., 2001).

The selection process in dairy goat was evaluated by selection indexes. Basal population of 1,000 does, randomly mated by 50 unselected and unrelated bucks, was simulated. Eight selection indexes in two production systems (intensive - indexes I-IV and semi-intensive - indexes V-XIII) were compared. Three groups of dairy goats (A, B and C) were simulated with a respective intensity of 10, 25 and 50%. Each group was composed of five generations and each generation was replicated 20 times. All traits were simulated using matrices of direct additive genetic and the residual (co)variance and the effect of Mendelian segregation. Statistical analyses were performed by repeated measurements in time. Selection using the suggested indexes improved all traits. Selection indexes III and VII are suggested due to simultaneous production and reproduction trait improvement. Indexes IV and VIII are recommended when higher rates of total solids and somatic cell count occur and would correspond to differentiated payment for the milk. [Comparação de índices de seleção de caprinos leiteiros em regiões tropicais]. Resumo: Objetivou-se avaliar o processo de seleção de caprinos leiteiros utilizando-se índices de seleção. Foi simulada população a base composta por 1.000 fêmeas, acasaladas aleatoriamente com 50 reprodutores, não selecionados e não aparentados. Foram comparados oito índices de seleção em cada sistema de criação: intensivo (índices I-IV) e semi-intensivo (índices V-VIII). Foram simulados três grupos de caprinos leiteiros (A, B e C), utilizando-se intensidade de seleção de 10, 25 e 50%, respectivamente. Cada grupo foi composto por cinco gerações e cada geração foi replicada 20 vezes. Todas as características foram simuladas utilizando-se as matrizes de (co) variância genética aditiva direta, residual e o efeito da segregação Mendeliana. As análises estatísticas foram realizadas por meio de medidas repetidas no tempo. A seleção realizada por meio dos índices propostos promoveu melhorias em todas as características. Sugere-se a utilização dos índices III e VII, por promoverem melhorias simultâneas nas características produtivas e reprodutivas. Da mesma forma, sugere-se a utilização dos índices IV e VIII havendo pagamento diferenciado por maiores teores de sólidos totais e à contagem de células somáticas.

Genetic association studies, pharmacological investigations and analysis of mice-lacking individual genes have made it clear that Cocaine administration and Withdrawal have a profound impact on multiple neurotransmitter systems. The GABAergic medium spiny neurons of the nucleus accumbens (NAc) exhibit changes in the expression of genes encoding receptors for glutamate and in the signaling pathways triggered by dopamine binding to G-protein-coupled dopamine receptors. Deep sequence analysis provides a sensitive, quantitative and global analysis of the effects of Cocaine on the NAc transcriptome. RNA prepared from the NAc of adult male mice receiving daily injections of Saline or Cocaine, or Cocaine followed by a period of Withdrawal, was used for high-throughput sequence analysis. Changes were validated by quantitative polymerase chain reaction or Western blot. On the basis of pathway analysis, a preponderance of the genes affected by Cocaine and Withdrawal was involved in the cadherin, heterotrimeric G-protein and Wnt signaling pathways. Distinct subsets of cadherins and protocadherins exhibited a sustained increase or decrease in expression. Sustained down-regulation of several heterotrimeric G-protein β- and γ-subunits was observed. In addition to altered expression of receptors for small molecule neurotransmitters, neuropeptides and endocannabinoids, changes in the expression of plasma membrane transporters and vesicular neurotransmitter transporters were also observed. The effects of chronic Cocaine and Withdrawal on the expression of genes essential to cholinergic, glutamatergic, GABAergic, peptidergic and endocannabinoid signaling are as profound as their effects on dopaminergic transmission. Simultaneous targeting of multiple Withdrawal-specific changes in gene expression may facilitate development of new therapeutic approaches that are better able to prevent relapse.

Brazil has high climate, soil and environmental diversity, as well as distinct socioeconomic and political realities, what results in differences among the political administrative regions of the country. The objective of this study was to determine spatial distribution of the physical, climatic and socioeconomic aspects that best characterize the production of dairy goats in Brazil. Production indices of milk per goat, goat production, milk production, as well as temperature range, mean temperature, precipitation, normalized difference vegetation index, relative humidity, altitude, agricultural farms; farms with native pasture, farms with good quality pasture, farms with water resources, farms that receive technical guidance, family farming properties, non-familiar farms and the human development index were evaluated. The multivariate analyses were carried out to spatialize climatic, physical and socioeconomic variables and so differenciate the Brazilian States and Regions. The highest yields of milk and goat production were observed in the Northeast. The Southeast Region had the second highest production of milk, followed by the South, Midwest and North. Multivariate analysis revealed distinctions between clusters of political-administrative regions of Brazil. The climatic variables were most important to discriminate between regions of Brazil. Therefore, it is necessary to implement animal breeding programs to meet the needs of each region. [Espacialização de fatores climáticos, físicos e socioeconômicos que afetam a produção de caprinos leiteiros no Brasil e seu impacto sobre as decisões em melhoramento animal]. Resumo: O Brasil possui diversidade edafoclimática e realidades socioeconômicas e políticas distintas. Isto contribui para diferenciar as regiões político administrativas do país. Objetivou-se espacializar os fatores físicos, climáticos e socioeconômicos que melhor discriminam a produção de caprinos leiteiros no Brasil. Foram analisados índice de produção de leite por cabra; índice de produção de caprinos; índice de produção de leite, amplitude da temperatura; temperatura média; precipitação; índice normalizado de diferença vegetativa; umidade relativa do ar; altitude; estabelecimentos agropecuários; estabelecimentos com pastagem nativa; estabelecimentos com pastagens de boa qualidade; estabelecimentos com recursos hídricos; estabelecimentos que recebem orientação técnica; estabelecimentos de agricultura familiar; estabelecimentos de agricultura não familiar e índice de desenvolvimento humano. Foram realizadas análises multivariadas para espacializar as variáveis climáticas, físicas e socioeconômicas e, assim, discriminar os Estados e Regiões brasileiras. As maiores produções de caprinos e de leite foram observadas na região Nordeste. A região Sudeste apresentou segunda maior produção de leite, seguido pelo Sul, Centro-Oeste e Norte. As médias para produtividade mostraram que as regiões Centro-Oeste e Sudeste apresentaram animais mais especializados a produção de leite. As análises multivariadas evidenciaram distinções entre clusters das regiões político-administrativas do Brasil. As variáveis climáticas foram as mais importantes para discriminar entre as regiões brasileiras. A heterogeneidade dos componentes climáticos, físicos e socioeconômicos evidenciou peculiaridades em cada região. Portanto, é preciso implementar programas de melhoramento genético animal que atendam as necessidades de cada região.

Made available in DSpace on 2018-01-26T23:38:12Z (GMT). No. of bitstreams: 1 Geneticdiversity.pdf: 471993 bytes, checksum: 382850948118442498d18a018a96330c (MD5) Previous issue date: 2013-01-30

Este experimento foi conduzido para avaliar o desempenho de suínos criados em cama sobreposta, foram utilizados 480 animais, distribuídos em delineamento de blocos ao acaso, num arranjo fatorial 2 x 2 (cruzamentos x sexos), com três repetições de quarenta animais por unidade experimental. Foi avaliada a espessura de toucinho (ET) entre a 10ª e 11ª costela e na altura P2 e área de olho de lombo (AOL) utilizando-se ultra-som em tempo real e as características de desempenho. Verificou-se que houve efeito do sexo, onde machos apresentaram resultados superiores para consumo semanal (CS) e diário (CD) de ração, entretanto, a conversão (CA) e eficiência alimentar (EA) apresentaram resultados inferiores quando comparados às fêmeas. Não se observou efeito no ganho de peso diário (GPD) e peso final (PF), entre macho e fêmea. Suínos provenientes de ambos os cruzamentos e sexos apresentaram resultados satisfatórios e podem ser produzidos no sistema de cama sobreposta, entretanto, as fêmeas suínas apresentaram melhor desempenho zootécnico. This experiment was conducted to evaluate the swine performance in deep bedding breeding. Were used 480 pigs in an experimental design of randomized blocks, and fatorial arrangement 2 x 2 (crossbreeding x sex), with three replications and forty animals per experimental unit. Were evaluated the pigs performance traits, backfat thickness (ET) between 10th and 11th rib and in the P2 height and loin eye area (AOL) using real-time ultrasond during the experimental period. Sex effect was verified: male presented results better than female for weekly intake (CS) and daily feed intake (CD); however, feed: gain ratio (CA) and feed efficiency (EA) for male were worse than females. There were not differences in average daily gain (GPD), between males and females. Animals from both crossbreeding and sexes showed satisfactory results, perhaps, swine females showed better performance than male and can be used in deep bedding breeding.

Avaliou-se o desempenho de ovinos da raça Santa Inês, em três gramíneas forrageiras tropicais (A. gayanus Kunth. cv. Planaltina, P. maximum Jacq. cv. Aruana e P. maximum Jacq. cv. Tanzânia), em pastejo rotacionado, com período de ocupação de 14 dias e lotação fixa de 22 animais/ha, no período da seca. O período experimental foi de 82 dias, onde o desempenho de 11 borregos, em cada tratamento, foi acompanhado em um delineamento inteiramente casualizado. Com o avançar da seca foram utilizados níveis crescentes de 300, 400 e 500 g/animal/dia de suplementação concentrada para os três tratamentos. Nas forragens foram colhidas amostras a cada 14 dias para efetuar as análises bromatológicas. Através da verificação do peso dos animais, realizadas a cada 14 dias, foram obtidos o peso vivo, o ganho médio diário (GMD), o peso final (PF), o ganho acumulado (GAC) e a condição corporal (CC). Os ovinos alimentados com Aruana e Tanzânia apresentaram GMD de 93,6 e 92,0 g/animal/dia, respectivamente não diferindo entre si (p>0,05), mas foram superiores aos do Andropogon 35,6 g/animal/dia (p0.05). The animals on Andropogon pasture showed a mean weight gain of 35.6 g/animal/day. For PF, GAC and CC the treatments Aruana and Tanzânia showed the best results (p

Made available in DSpace on 2017-08-10T23:47:07Z (GMT). No. of bitstreams: 1 PresentStatusofConservation.pdf: 574606 bytes, checksum: 3cfa4e8f809031316bbd687d827f8ed3 (MD5) Previous issue date: 2009-09-16

Foram avaliadas as características de carcaça, os componentes não-carcaça e o rendimento da 12a costela de cordeiros Santa Inês terminados em pastejo rotacionado com três forrageiras tropicais (A. gayanus Kunth, cv. Planaltina,P. maximum Jacq., cv. Aruana e P. maximum Jacq., cv. Tanzânia), no período seco do ano. Utilizou-se delineamento inteiramente casualizado, com 11 ovinos (3 meses de idade e 18,8 ± 2,88 kg PV) em cada tratamento. Os animais receberam suplementação com concentrado em níveis crescentes, conforme o avançar do período seco, além de sal mineral à vontade. Ao final de 82 diasde experimento, os animais foram abatidos; no dia anterior ao abate, a área de olho-de-lombo (AOL) foi mensurada com ultra-som (AOLUS). Avaliaram-se o peso ao abate (PA), o peso de carcaça quente (PCQ), o rendimento de carcaça quente (RCQ), o comprimento da carcaça (CC), o escore de gordura subcutânea (EGS), o peso da meia-carcaça quente (PMCQ), os cortes da meia-carcaça (costela/fralda, costeleta, lombo, paleta, pernil, e pescoço) e os pesos da pele (PELE), das vísceras torácicas (VT) e abdominais (VA) e dos testículos (TE). A 12a costela foi avaliada quanto ao peso total (PT), AOL, aos pesos e às porcentagens de músculo (MUSC), osso (OSSO) e gordura (GORD) e os constituintes químicos. As características PA, PCQ, RCQ, PELE e GORD não diferiram entre os animais terminados em pastos de capim-aruana e capim-tanzânia, mas foram superiores nos animais terminados em pasto de capim-andropogon. Os rendimentos de pescoço, costela/fralda e costeleta dos animais terminados em capim-tanzânia foram superiores aos obtidos nos animais terminados em capim-andropogon e aruana, que não diferiram entre si. As demais características de carcaça, dos componentes não-carcaça e da 12a costela não diferiram entre os tratamentos. Os ovinos mantidos em pastagem de capim-aruana e capim-tanzânia apresentaram melhores características de carcaça e desempenho mais satisfatório em comparação aos terminados em pasto de capim-andropogon.

Made available in DSpace on 2022-08-30T19:19:37Z (GMT). No. of bitstreams: 1 document.pdf: 183739 bytes, checksum: a65883ff169dd5e63f9975b022f83c0a (MD5) Previous issue date: 2007

Made available in DSpace on 2018-06-07T01:04:01Z (GMT). No. of bitstreams: 1 ID292091.pdf: 342658 bytes, checksum: 198ea20990f773e4bc767cd86aa1bc08 (MD5) Previous issue date: 2008-02-25

Made available in DSpace on 2018-06-07T00:54:30Z (GMT). No. of bitstreams: 1 ID290561.pdf: 182780 bytes, checksum: 0cdf29f80d47fc110d8220bb439ac74e (MD5) Previous issue date: 2008-02-12

Made available in DSpace on 2022-07-08T17:19:49Z (GMT). No. of bitstreams: 1 49520745.pdf: 149871 bytes, checksum: 2474cd4621a95710eb60b4515ad27f86 (MD5) Previous issue date: 2005

Made available in DSpace on 2018-06-06T00:58:35Z (GMT). No. of bitstreams: 1 ID278101.pdf: 88655 bytes, checksum: ad66fec8695cc2d52bc475f0eb728fa3 (MD5) Previous issue date: 2007-01-05

Made available in DSpace on 2018-06-05T00:42:03Z (GMT). No. of bitstreams: 1 ID278001.pdf: 119162 bytes, checksum: ac5807481c336bba3b55205833b4acf2 (MD5) Previous issue date: 2007-01-05

Objetivou-se no presente trabalho investigar os efeitos de alguns fatores ambientais e estimar componentes de (co)variâncias e parâmetros genéticos para as características produtivas de peso à desmama (PD) e aos 18 meses (P18) e características reprodutivas de perímetro escrotal aos 18 meses (PE18), intervalo de partos (IEP) e fertilidade real (FR), idade ao primeiro parto (IPP) e data de parto (DP) de fêmeas Nelore, em um rebanho do Estado de Mato Grosso do Sul. As observações, referentes aos fatores ambientais, foram analisadas pelo método dos quadrados mínimos, cujos modelos estatísticos incluíram os efeitos fixos de ano (AN) e mês de nascimento (MN), a interação AN*MN, sexo (S) do animal (exceto para P18, PE18 e IPP) ou do bezerro e ordem do parto. Verificaram-se efeitos significativos de todos os fatores estudados sobre PD, com os mais leves em agosto (179 kg) e os mais pesados em dezembro (156 kg). Os machos (172 kg) foram 7,4% mais pesados que as fêmeas (162 kg). O P18 foi influenciado apenas pelo ano de nascimento. Não foi observada tendência, ao longo dos anos, para esta característica. Observou-se que somente a ordem do parto não influenciou o PE18 (média 281 kg). Todos os efeitos foram significativos para IEP (média 465 dias), com exceção do sexo do bezerro, que não apresentou influência significativa. A FR foi influenciada por todos os efeitos, apresentando valor médio de 144 kg. IPP (média 1.279 dias ou 41,93 meses) e DP sofreram influência dos efeitos fixos de mês e ano de nascimento, havendo também interação entre mês e ano de nascimento neste caso. Com base nas estimativas de herdabilidade, ambiente permanente, correlações genéticas e fenotípicas, calculadas por meio do programa MTDFREML, concluiu-se que as características estudadas podem responder à seleção direta, com exceção da FR e da IPP. As correlações genéticas entre as características produtivas estudadas foram favoráveis, indicando possibilidade na obtenção de progressos genéticos indiretos. The objective of the present work was to investigate the effects of some genetic and environmental factors on production (weaning weight WW; eighteen month weight W18) and reproduction (scrotal perimeter at 18 months SP18; calving interval CI; age at first calving AFC; True fertility TF, calving date CD) traits in a Nellore cattle herd in the Mato Grosso do Sul State, Brazil. The observations were analysed using the least squares methodology, and the statistical models included the fixed effects: year (YB) and month (MB) of calving, interaction YB*MB, sex (S) of animal (except for W18, SP18 and AFC) and calving number. Significant effects were found for all factors studied on WW, and animals born in August (179 kg) and December (156 kg) had highest and lowest WW respectively. The male calves (174 kg) were heavier at weaning than females (162 kg), a difference of 7.4% in favour of males. No tendency was observed in terms of mean values over the years for this trait. W18 was influenced only by birth year, with a mean value of 281.0 kg. Only calving number did not influence Scrotal perimeter (SP18), which had a mean value of 26.8 cm. The mean CI was 465 days, and all effects were significant, except for calf sex. TF was significantly influenced by all effects studied, and had a mean value of 144 kg. Age at first calving was high (1.279 days or 41.93 months) and influenced by month and year of calving. In terms of calving date, month and year were significant effects, as was the interaction between these effects but sex and calving number did not affect this trait. Based on estimates of heritability, permanent environment, as well as on genetic and phenotypic correlations, estimated using MTDFREML, it was concluded that these traits should respond to direct selection, except for RF and AFP. Genetic correlations between production traits were favourable, indicating the possibility of genetic progress through indirect selection.

Made available in DSpace on 2018-05-30T00:45:42Z (GMT). No. of bitstreams: 1 ID230181.pdf: 80417 bytes, checksum: ec808772059222c77e12875285444994 (MD5) Previous issue date: 2002-11-28

Made available in DSpace on 2018-05-30T00:45:54Z (GMT). No. of bitstreams: 1 230191.pdf: 86481 bytes, checksum: 2d3f8a48c5de4a15cfd2a19c45af840b (MD5) Previous issue date: 2002-11-28