Onset of puberty was observed in 12 bison bulls by the collection of semen at monthly intervals for 12 months beginning at 13 months of age. Onset of puberty was defined as the time in development when an ejaculate contained a minimum of 50x106 sperm showing at least 10% progressive motility. At each collection, data were recorded on body weight, semen quality, fecal testosterone concentration, and physical development. Semen was evaluated for gross motility, individual progressive motility, sperm morphology, sperm concentration and volume. From these data bison bulls attained onset of puberty at an average age of 16.5 months and an average body weight of 353 ± 52.8 kg. Age was the greatest determining factor for onset of puberty in this group of bulls. <p> Monthly abattoir collections of epididymal sperm (n=288) and testicular tissue (n=120) were evaluated to determine if bison bulls undergo seasonal changes in sperm production. Although epididymal sperm morphology did not give any indication of seasonal variation, the histological study of testicular tissue showed greater seminiferous tubule diameter (27.0 ± 4.3 ìm) during the breeding months (July, August and September) than during any other seasons. Semen collected at 4 different occasions during the year (June, November, January, and April) from live mature breeding bulls (n=21) was used to verify data collected from abattoir samples. Semen from mature bulls showed a significantly greater proportion of normal sperm in June than in November (73.8 ± 9.1%; 44.1 ± 24.3%), respectively. There was little improvement in sperm morphology at the January sampling but in April morphology improved to a level close to that observed in June. Fecal testosterone concentrations were highest in June (128.6 ± 67.4 ng/g) and lowest in April (48.5 ± 33.3 ng/g). Although there was no clear seasonal trend in sperm morphology from bulls sampled at the abattoir, mature bulls showed slight seasonal variations in semen quality.

Onset of puberty was observed in 12 bison bulls by the collection of semen at monthly intervals for 12 months beginning at 13 months of age. Onset of puberty was defined as the time in development when an ejaculate contained a minimum of 50x106 sperm showing at least 10% progressive motility. At each collection, data were recorded on body weight, semen quality, fecal testosterone concentration, and physical development. Semen was evaluated for gross motility, individual progressive motility, sperm morphology, sperm concentration and volume. From these data bison bulls attained onset of puberty at an average age of 16.5 months and an average body weight of 353 ± 52.8 kg. Age was the greatest determining factor for onset of puberty in this group of bulls. <p> Monthly abattoir collections of epididymal sperm (n=288) and testicular tissue (n=120) were evaluated to determine if bison bulls undergo seasonal changes in sperm production. Although epididymal sperm morphology did not give any indication of seasonal variation, the histological study of testicular tissue showed greater seminiferous tubule diameter (27.0 ± 4.3 ìm) during the breeding months (July, August and September) than during any other seasons. Semen collected at 4 different occasions during the year (June, November, January, and April) from live mature breeding bulls (n=21) was used to verify data collected from abattoir samples. Semen from mature bulls showed a significantly greater proportion of normal sperm in June than in November (73.8 ± 9.1%; 44.1 ± 24.3%), respectively. There was little improvement in sperm morphology at the January sampling but in April morphology improved to a level close to that observed in June. Fecal testosterone concentrations were highest in June (128.6 ± 67.4 ng/g) and lowest in April (48.5 ± 33.3 ng/g). Although there was no clear seasonal trend in sperm morphology from bulls sampled at the abattoir, mature bulls showed slight seasonal variations in semen quality.

Master of Science in Veterinary Biomedical Science / Department of Clinical Sciences / Robert L. Larson / The selection of young replacement animals can have a significant impact on beef herd reproductive performance. Replacement heifers can be utilized to improve reproductive performance by replacing mature animals that failed to meet the production with young, cycling heifers that can have the potential of improving the reproductive momentum of a herd. The use of yearling bulls in natural breeding herds has the advantage of shortening the generational interval of the herd and has the potential of reducing the cost per cow exposed as additions to the bull battery. This thesis involves two studies that investigated methods used for the selection of peripubertal replacement animals in beef herds. The first study evaluated the ability of the novel Ready-Intermediate-Problem (RIP) replacement heifer evaluation matrix to classify heifers into groups that allow producers to select for replacements that meet production goals. Beef heifers (n=341) were classified according to the RIP matrix guidelines and then exposed to AI breeding, bull breeding, or a combination of both as per the management plans for each participating herd. Following breeding season the heifers were evaluated to determine pregnancy status, pregnancy status to single AI exposure, days bred, and the number of 21 day cycles needed during breeding season to become pregnant. After breeding season, 298 (87%) of the heifers were pregnant, 204 (68%) of which became pregnant in the first 21 days of the breeding season. Probability of overall pregnancy and pregnancy after single AI exposure was not significantly associated with RIP classification. There was a significant interaction in RIP classification by 21 day cycle. The second study was a retrospective study using BSE result data to determine the proportion of yearling beef bulls that are classified as satisfactory potential breeders when reevaluated after failing their initial breeding soundness evaluation (BSE) and to identify any predictive factors at initial BSE for satisfactory performance at revaluation. The study included 2,805 beef bulls between 11 and 14 months of age at first BSE evaluated at KABSU from 2006 to 2014. Generalized linear mixed models were created to assess potential associations among breed, age, and interaction between breed and age and passing the initial evaluation and identify predictive factors for risk of passing BSE after initial failure. The majority (93%) of the study bulls passed one of up to three BSEs. There was a significant interaction between age and breed of bull at initial BSE. Identification of suitable peripubertal replacement animals that will improve herd reproductive performance remains a challenge for producers. There are several factors that can affect replacement animals’ ability to perform according to expectations at the beginning of the breeding season. Classification of heifers into categories that can predict performance during breeding season with reasonable confidence can assist producers in identifying heifers that complement the reproductive performance goals of the herd. Utilizing BSE to identify bulls that have adequate semen quality as well as other traits important for breeding soundness is similarly important in reducing the risks of using young bulls for breeding.

Resumo: Diante do grande impacto da fertilidade dos touros sobre as eficiências reprodutiva e produtiva em rebanhos comerciais, o presente trabalho foi realizado visando avaliar as características testiculares e seminais como critérios de seleção de touros jovens da raça Nelore. As correlações fenotípicas foram, de modo geral, baixas ou nulas (P<0,01) entre as características testiculares, seminais e de crescimento. Todas as características testiculares ou seminais deverão ser contempladas no exame andrológico, visto a independência existente entre as mesmas e a importância destas na comprovação da fertilidade de touros. Os componentes de (co)variância e os valores genéticos foram estimados pelo método da amostragem de Gibbs pelo programa GIBBS2F90, sob modelo animal, o qual incluiu como efeitos fixos, os grupos de contemporâneos e a idade do animal e como aleatório o efeito genético aditivo direto. As estimativas de herdabilidade para perímetro escrotal aos 18 meses, perímetro escrotal no andrológico, volume testicular, formato testicular, aptidão andrológica, defeitos espermáticos maiores, menores e totais foram: 0,42; 0,41; 0,23; 0,22; 0,10; 0,16; 0,04 e 0,15. As correlações genéticas entre perímetro escrotal aos 18 meses com as demais características testiculares e aptidão andrológica foram baixas a altas, de 0,20 a 0,84 e, baixas com as seminais, de -0,16 a -0,24. A circunferência escrotal como critério de seleção deverá promover ganho genético rápido por seleção individual e, por resposta correlacionada, aumento do volume testicular, mudança para formas mais esféricas dos testículos, melhoria da qualidade seminal e aumento do número de animais aptos à reprodução nas condições extensivas de criação no Brasil. / Abstract: Considering the great impact of fertility of bulls on reproductive and productive efficiency in commercial herds, the objective of this study was to evaluate the testicular and seminal traits as selection criteria of Nellore young bulls. The residual correlations between the traits were analyzed and, in general, the phenotypic associations were small (P<0.01) or null between the testicular, seminal and growth traits. The testicular or seminal traits should be considered in breeding soundness examination, due to their independence of each other and the importance to fertility of bulls. The genetic (co)variance components and genetic values were estimated by the Gibbs sampling method, using the program GIBBS2F90, under an animal model, which included, as fixed effects, the contemporary groups and animal age and, as random effect, the additive genetic effect. The heritability estimates for scrotal circumference at 18 months, scrotal circumference, testicular volume, testicular format, breeding soundness classification, major sperm defects, minor and total sperm defects were: 0.42, 0.41, 0.23, 0.22, 0.10., 0.16, 0.04 and 0.15. Genetic correlations between scrotal circumference at 18 months and others testicular traits and breeding soundness classification were low to high (0.20 to 0.84) and, with seminal traits was low (-0.16 to - 0.24). The scrotal circumference as a selection criterion should result in rapid genetic gain by individual selection, and as correlated response, should result in testicular volume, changes to more spherical shapes of the testicles, improved sperm quality and increased number of satisfactory bulls for breeding under extensive conditions in Brazil. / Orientadora: Lúcia Galvão de Albuquerque / Coorientador: Joanir Pereira Eler / Banca: José Bento Sterman Ferraz / Banca: José Domingos Guimarães / Banca: Humberto Tonhati / Banca: Maurício Mello de Alencar / Doutor

Made available in DSpace on 2016-12-08T16:24:03Z (GMT). No. of bitstreams: 1 PGCV07MA024.pdf: 1167481 bytes, checksum: 8d46ea0fb9ff81da5a38a6f48e0ef3e1 (MD5) Previous issue date: 2007-06-15 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The aims of this work were to perform a breeding soundness evaluation in Devon bulls in the State of Santa Catarina, in Southern Brazil, and to propose alternatives to maximize beef cattle production capacity. The contents of this dissertation were divided in four chapters. Chapter one is a review on the breeding soundness evaluation of bulls, which includes clinical exam, semen collection and evaluation, and serving capacity. In Chapter two, the evaluation of the breeding soundness of 207 Devon bulls was used to determine approval rate, based on clinical and seminal evaluation and serving capacity, and potential causes for failure. The bulls approval mean rate was 71.6%. The mean scrotal circumference (CE), according to distinct age periods, was 35.2 ± 2.93 cm for bulls between 18 to 22 months of age; 37.3 ± 2.75 cm for 23 to 27 months, and 38.2 ± 3.6 cm for 30 months or above. In Chapter 3, the internal artificial vagina (IAV) methodology, designed by Dr. Albert Barth, was tested in Devon bulls, simultaneously evaluating their serving capacity and fertility. Out of 52 bulls tested, 60.0% were satisfactory. A semen sample was obtained with the aid of the IAV in 45 bulls (86.5%), from which, 69.0% were approved in the breeding soundness evaluation, and 31.0% were reproved. When the total umber of bulls (n=52) was considered, 60.0% were approved after semen collection and serving capacity using the IAV. The IAV was an effective alternative for semen collection, allowing the simultaneous evaluation of semen quality and serving capacity. The IAV procedures were proven very effective and important, as 11.1% of failed bulls would have been inadequately approved if only clinical and seminal exams were performed. Chapter 4 reports a study to evaluate OPU recovery and efficiency of vitrification in immature OPU or slaughterhouse oocytes, from Devon viii and Nelore cows. Devon OPU mean collection rate was of 4.6 oocytes/female, hich was significantly lower (p<0.05) than in Nelore cows (16.3 oocytes/female). After warming, in vitro maturation, fertilization and culture of vitrified oocytes, cleavage rates were 17.6% in the OPU/Devon group, 29.1% in OPU/Nelore, 22.8% in the slaughterhouse/Devon, and 14.5% in the slaughterhouse/Nelore group. No statistical difference was observed between groups (p>0.05). Only one embryo developed to the blastocyst stage in the OPU/Devon group. Nelore cows had a higher OPU recovery per session in comparison to Devon. We concluded that immature oocyte vitrification obtained by OPU, under field conditions, did not allow acceptable in vitro embryo developmental rates. In conclusion, this study demonstrated the feasibility oftechnical alternatives to improve bovine reproductive capacity, but such alternatives should be tested beforehand and properly adapted previously to the use under field conditions / O objetivo deste trabalho foi avaliar a capacidade reprodutiva de touros da raça Devon, criados em Santa Catarina, bem como propor alternativas para maximizar a capacidade produtiva de bovinos de corte. Os conteúdos foram agrupados em quatro capítulos. No Capítulo 1, procedeu-se a revisão bibliográfica do exame andrológico do touro, incluindo o exame clínico, a coleta do ejaculado, a avaliação seminal e a avaliação da capacidade de serviço. No Capítulo 2, foram avaliados dados obtidos de exames andrológicos de 207 touros da raça Devon, sendo determinado o percentual de animais aptos à reprodução, com base no exame clinico, exame seminal e comportamento sexual, bem como as potenciais causas de reprovação. A média de touros aprovados foi de 71,6%. A média de circunferência escrotal (CE) nas diferentes faixas etárias foram 35,2 ± 2,93 cm para animais de 18 a 22 meses, 37,3 ± 2,75 cm para animais de 23 a 27 meses e 38,2 ± 3,6 cm para animais com mais de 30 meses. No Capítulo 3, foi avaliada a metodologia da vagina artificial interna (VAI) proposta pelo Dr. Albert Barth, como forma de coleta do ejaculado e simultânea avaliação do comportamento e a fertilidade de touros da raça Devon. Dos 52 animais examinados, 60,0% foram considerados aptos. A VAI possibilitou a coleta do ejaculado de 45 animais (86,5%). Dos touros coletados com a VAI (n=45) 69% foram considerados aptos à reprodução e 31% inaptos. Quando se considerou o total de touros examinados (n=52), 60,0% dos touros foram aprovados após coleta de sêmen e avaliação da capacidade de cópula com a VAI. Concluiu-se que a VAI foi efetiva na coleta dos ejaculados, permitindo a avaliação simultânea da capacidade de serviço. A técnica mostrou-se importante, já que vi 11,1% dos animais reprovados no teste seriam inadequadamente considerados aptos à reprodução, se apenas os exames clínico e de qualidade seminal fossem empregados. O Capítulo 4 reporta um estudo para avaliar a taxa de recuperação e a eficiência da vitrificação de oócitos imaturos obtidos por OPU, ou de ovários de abatedouro, de fêmeas bovinas das raças Devon e Nelore. O número médio de oócitos por sessão de OPU foi de 4,6 na raça Devon, sendo inferior (p<0,05) aos 16,3 obtidos na raça Nelore. Após o reaquecimento, maturação, fecundação e cultivo dos oócitos vitrificados, foram observadas taxas de clivagem de 17,6% no grupo OPU / Devon, 29,1% no grupo OPU / Nelore, 22,8% no grupo ovários abatedouro / Devon e 14,5% no grupo ovários abatedouro / Nelore, não havendodiferença (p>0,05) entre os grupos. Na avaliação do desenvolvimento embrionário, apenas um embrião atingiu o estágio de blastocisto, no grupo OPU / Devon. As fêmeas da raça Nelore possibilitaram um número significativamente maior de oócitos recuperados por sessão quando comparadas com fêmeas da raça Devon. Concluise que a associação da técnica de OPU com vitrificação dos oócitos, em condições de campo, não produz taxas aceitáveis de desenvolvimento embrionário. O estudo demonstra que existem alternativas para melhorar a capacidade reprodutiva de bovinos que, todavia, devem ser previamente avaliadas e adequadas às condições existentes

Made available in DSpace on 2016-12-08T16:24:06Z (GMT). No. of bitstreams: 1 PGCV07MA024.pdf: 1167481 bytes, checksum: 8d46ea0fb9ff81da5a38a6f48e0ef3e1 (MD5) Previous issue date: 2007-06-14 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The aims of this work were to perform a breeding soundness evaluation in Devon bulls in the State of Santa Catarina, in Southern Brazil, and to propose alternatives to maximize beef cattle production capacity. The contents of this dissertation were divided in four chapters. Chapter one is a review on the breeding soundness evaluation of bulls, which includes clinical exam, semen collection and evaluation, and serving capacity. In Chapter two, the evaluation of the breeding soundness of 207 Devon bulls was used to determine approval rate, based on clinical and seminal evaluation and serving capacity, and potential causes for failure. The bulls approval mean rate was 71.6%. The mean scrotal circumference (CE), according to distinct age periods, was 35.2 ± 2.93 cm for bulls between 18 to 22 months of age; 37.3 ± 2.75 cm for 23 to 27 months, and 38.2 ± 3.6 cm for 30 months or above. In Chapter 3, the internal artificial vagina (IAV) methodology, designed by Dr. Albert Barth, was tested in Devon bulls, simultaneously evaluating their serving capacity and fertility. Out of 52 bulls tested, 60.0% were satisfactory. A semen sample was obtained with the aid of the IAV in 45 bulls (86.5%), from which, 69.0% were approved in the breeding soundness evaluation, and 31.0% were reproved. When the total number of bulls (n=52) was considered, 60.0% were approved after semen collection and serving capacity using the IAV. The IAV was an effective alternative for semen collection, allowing the simultaneous evaluation of semen quality and serving capacity. The IAV procedures were proven very effective and important, as 11.1% of failed bulls would have been inadequately approved if only clinical and seminal exams were performed. Chapter 4 reports a study to evaluate OPU recovery and efficiency of vitrification in immature OPU or slaughterhouse oocytes, from Devon viii and Nelore cows. Devon OPU mean collection rate was of 4.6 oocytes/female, which was significantly lower (p<0.05) than in Nelore cows (16.3 oocytes/female). After warming, in vitro maturation, fertilization and culture of vitrified oocytes, cleavage rates were 17.6% in the OPU/Devon group, 29.1% in OPU/Nelore, 22.8% in the slaughterhouse/Devon, and 14.5% in the slaughterhouse/Nelore group. No statistical difference was observed between groups (p>0.05). Only one embryo developed to the blastocyst stage in the OPU/Devon group. Nelore cows had a higher OPU recovery per session in comparison to Devon. We concluded that immature oocyte vitrification obtained by OPU, under field conditions, did not allow acceptable in vitro embryo developmental rates. In conclusion, this study demonstrated the feasibility of technical alternatives to improve bovine reproductive capacity, but such alternatives should be tested beforehand and properly adapted previously to the use under field conditions / O objetivo deste trabalho foi avaliar a capacidade reprodutiva de touros da raça Devon, criados em Santa Catarina, bem como propor alternativas para maximizar a capacidade produtiva de bovinos de corte. Os conteúdos foram agrupados em quatro capítulos. No Capítulo 1, procedeu-se a revisão bibliográfica do exame andrológico do touro, incluindo o exame clínico, a coleta do ejaculado, a avaliação seminal e a avaliação da capacidade de serviço. No Capítulo 2, foram avaliados dados obtidos de exames andrológicos de 207 touros da raça Devon, sendo determinado o percentual de animais aptos à reprodução, com base no exame clinico, exame seminal e comportamento sexual, bem como as potenciais causas de reprovação. A média de touros aprovados foi de 71,6%. A média de circunferência escrotal (CE) nas diferentes faixas etárias foram 35,2 ± 2,93 cm para animais de 18 a 22 meses, 37,3 ± 2,75 cm para animais de 23 a 27 meses e 38,2 ± 3,6 cm para animais com mais de 30 meses. No Capítulo 3, foi avaliada a metodologia da vagina artificial interna (VAI) proposta pelo Dr. Albert Barth, como forma de coleta do ejaculado e simultânea avaliação do comportamento e a fertilidade de touros da raça Devon. Dos 52 animais examinados, 60,0% foram considerados aptos. A VAI possibilitou a coleta do ejaculado de 45 animais (86,5%). Dos touros coletados com a VAI (n=45) 69% foram considerados aptos à reprodução e 31% inaptos. Quando se considerou o total de touros examinados (n=52), 60,0% dos touros foram aprovados após coleta de sêmen e avaliação da capacidade de cópula com a VAI. Concluiu-se que a VAI foi efetiva na coleta dos ejaculados, permitindo a avaliação simultânea da capacidade de serviço. A técnica mostrou-se importante, já que vi 11,1% dos animais reprovados no teste seriam inadequadamente considerados aptos à reprodução, se apenas os exames clínico e de qualidade seminal fossem empregados. O Capítulo 4 reporta um estudo para avaliar a taxa de recuperação e a eficiência da vitrificação de oócitos imaturos obtidos por OPU, ou de ovários de abatedouro, de fêmeas bovinas das raças Devon e Nelore. O número médio de oócitos por sessão de OPU foi de 4,6 na raça Devon, sendo inferior (p<0,05) aos 16,3 obtidos na raça Nelore. Após o reaquecimento, maturação, fecundação e cultivo dos oócitos vitrificados, foram observadas taxas de clivagem de 17,6% no grupo OPU / Devon, 29,1% no grupo OPU / Nelore, 22,8% no grupo ovários abatedouro / Devon e 14,5% no grupo ovários abatedouro / Nelore, não havendo diferença (p>0,05) entre os grupos. Na avaliação do desenvolvimento embrionário, apenas um embrião atingiu o estágio de blastocisto, no grupo OPU / Devon. As fêmeas da raça Nelore possibilitaram um número significativamente maior de oócitos recuperados por sessão quando comparadas com fêmeas da raça Devon. Concluise que a associação da técnica de OPU com vitrificação dos oócitos, em condições de campo, não produz taxas aceitáveis de desenvolvimento embrionário. O estudo demonstra que existem alternativas para melhorar a capacidade reprodutiva de bovinos que, todavia, devem ser previamente avaliadas e adequadas às condições existentes

Orientador: Márcio Garcia Ribeiro / Resumo: A leptospirose permanece como uma das zoonoses mais prevalentes de origem bacteriana em todo o mundo, particularmente em países de clima tropical. Devido às características peculiares das leptospiras, a doença é negligenciada ou subdiagnosticada em animais de produção. A maioria dos estudos com bovinos têm focado a doença apenas em vacas. Neste cenário, em virtude dos riscos de infecção do trato reprodutivo de touros e da eliminação do patógeno pelo sêmen, o presente estudo investigou a soroaglutinação microscópica (SAM) com antígenos vivos em 203 touros bovinos adultos em idade reprodutiva, em regime de monta natural, sem sinais aparentes de orquite ou inflamação de glândulas acessórias. Simultaneamente, o sêmen dos touros foi submetido ao exame andrológico e a reação em cadeia pela polimerase (PCR) convencional utilizando o gene 16S rRNA. Resultados positivos na PCR convencional foram confirmados por sequenciamento. A sêmen plasma aglutinação (SPA) modificada foi realizada substituindo o soro sanguíneo pelo plasma seminal no teste da SAM. O ejaculado de oito (8/203=3,9%) touros foi considerado inapto à reprodução (necrospermia e azoospermia). Não foram identificadas aglutininas anti-Leptospira na SPA. Foi observada alta frequência (132/203=65%) de títulos na SAM, particularmente para sorovares do sorogrupo Sejroe, e.g., Hardjo CTG (100/203=49,3%), Wolffi (74/203=36,4%), Guaricura (72/203=35,5%) e Hardjoprajitno (56/203=27,6%). O sêmen de três (3/203=1,5%) touros foram posit... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Made available in DSpace on 2014-06-11T19:33:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-18Bitstream added on 2014-06-13T20:25:12Z : No. of bitstreams: 1 silva_mr_dr_jabo.pdf: 414659 bytes, checksum: 6652a4427059f17af722c81fb586a4e3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Diante do grande impacto da fertilidade dos touros sobre as eficiências reprodutiva e produtiva em rebanhos comerciais, o presente trabalho foi realizado visando avaliar as características testiculares e seminais como critérios de seleção de touros jovens da raça Nelore. As correlações fenotípicas foram, de modo geral, baixas ou nulas (P<0,01) entre as características testiculares, seminais e de crescimento. Todas as características testiculares ou seminais deverão ser contempladas no exame andrológico, visto a independência existente entre as mesmas e a importância destas na comprovação da fertilidade de touros. Os componentes de (co)variância e os valores genéticos foram estimados pelo método da amostragem de Gibbs pelo programa GIBBS2F90, sob modelo animal, o qual incluiu como efeitos fixos, os grupos de contemporâneos e a idade do animal e como aleatório o efeito genético aditivo direto. As estimativas de herdabilidade para perímetro escrotal aos 18 meses, perímetro escrotal no andrológico, volume testicular, formato testicular, aptidão andrológica, defeitos espermáticos maiores, menores e totais foram: 0,42; 0,41; 0,23; 0,22; 0,10; 0,16; 0,04 e 0,15. As correlações genéticas entre perímetro escrotal aos 18 meses com as demais características testiculares e aptidão andrológica foram baixas a altas, de 0,20 a 0,84 e, baixas com as seminais, de -0,16 a -0,24. A circunferência escrotal como critério de seleção deverá promover ganho genético rápido por seleção individual e, por resposta correlacionada, aumento do volume testicular, mudança para formas mais esféricas dos testículos, melhoria da qualidade seminal e aumento do número de animais aptos à reprodução nas condições extensivas de criação no Brasil. / Considering the great impact of fertility of bulls on reproductive and productive efficiency in commercial herds, the objective of this study was to evaluate the testicular and seminal traits as selection criteria of Nellore young bulls. The residual correlations between the traits were analyzed and, in general, the phenotypic associations were small (P<0.01) or null between the testicular, seminal and growth traits. The testicular or seminal traits should be considered in breeding soundness examination, due to their independence of each other and the importance to fertility of bulls. The genetic (co)variance components and genetic values were estimated by the Gibbs sampling method, using the program GIBBS2F90, under an animal model, which included, as fixed effects, the contemporary groups and animal age and, as random effect, the additive genetic effect. The heritability estimates for scrotal circumference at 18 months, scrotal circumference, testicular volume, testicular format, breeding soundness classification, major sperm defects, minor and total sperm defects were: 0.42, 0.41, 0.23, 0.22, 0.10., 0.16, 0.04 and 0.15. Genetic correlations between scrotal circumference at 18 months and others testicular traits and breeding soundness classification were low to high (0.20 to 0.84) and, with seminal traits was low (-0.16 to - 0.24). The scrotal circumference as a selection criterion should result in rapid genetic gain by individual selection, and as correlated response, should result in testicular volume, changes to more spherical shapes of the testicles, improved sperm quality and increased number of satisfactory bulls for breeding under extensive conditions in Brazil.

Submitted by Ubirajara Cruz (ubirajara.cruz@gmail.com) on 2018-06-04T16:46:17Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_carlos_ferreira.pdf: 752331 bytes, checksum: 1791efb2b3372ab1fb6e88d0ec2a0e2f (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-06-05T11:53:24Z (GMT) No. of bitstreams: 2 tese_carlos_ferreira.pdf: 752331 bytes, checksum: 1791efb2b3372ab1fb6e88d0ec2a0e2f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-05T11:53:24Z (GMT). No. of bitstreams: 2 tese_carlos_ferreira.pdf: 752331 bytes, checksum: 1791efb2b3372ab1fb6e88d0ec2a0e2f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-22 / A fertilidade dos reprodutores é de suma importância para a maximização das taxas de prenhez e melhoramento genético. O exame andrológico é uma importante ferramenta para a identificação de reprodutores sub férteis e para o monitoramento da qualidade seminal. Porém, poucas características do exame estão correlacionadas com a fertilidade in vivo. Assim, é fundamental a identificação de métodos que possam auxiliar na seleção mais precisa dos futuros reprodutores. Os objetivos do primeiro trabalho foram avaliar as acurácias e o viés das predições genômicas, utilizando diferentes métodos, para a característica perímetro escrotal ajustado à idade e ajustado à idade e peso em touros das raças Hereford e Braford. Os valores estimados para a herdabilidade apresentaram magnitude moderada a alta (0,39 a 0,48), demonstrando que é possível a obtenção de ganhos genéticos a partir da seleção. A predição de valores genéticos utilizando informações genômicas pelos métodos índice de seleção e single-step possibilitou o aumento de acurácia (em torno de 30%) para as características estudadas. Os ganhos de acurácia obtidos com os métodos, combinando as informações tradicionais com a genômica em relação ao método BLUP tradicional indicam que as predições genômicas podem ser usadas como ferramenta para melhorar os ganhos genéticos e reduzir o intervalo de gerações. Já o segundo artigo teve como objetivos: determinar a expressão de RNAm das paraoxonases (PON) 1, 2 e 3 no parênquima testicular, vesículas seminais e epidídimo de touros, avaliar a atividade de PON1 na circulação sanguínea e no plasma seminal; e correlacionar esta atividade com características avaliadas durante o exame andrológico. A caracterização da expressão dos genes foi realizada por qRT-PCR e a determinação da atividade de PON1 foi realizada em amostras de soro e plasma seminal provenientes de 110 touros. As PON 1, 2 e 3 foram expressas no parênquima testicular dos animais analisados. Observou-se uma correlação positiva entre a atividade sérica e seminal de PON1 com diversos indicadores de fertilidade. / Male fertility is important to optimize pregnancy rates and genetic improvement. Breeding soundness evaluations are key tools to identify sub fertile males and to survey characteristics of sperm quality. However, few sperm quality traits are correlated with fertility in vivo. Thus, it is essential to identify methods that can assist in more precise selection of future bulls. The goals of the first study were to evaluate the accuracy and the bias of the genomic predictions, using different methods, for the characteristic scrotal perimeter adjusted to age and adjusted to age and weight in Hereford and Braford bulls. The estimates for the heritability showed moderate to high magnitude (0.39 to 0.48), demonstrating that it is possible to obtain genetic gains from selection. The prediction of genetic values using genomic information by methods of selection index and single-step made possible the increase of accuracy (around 30%) for the characteristics studied. The gains in accuracy obtained with the methods, combining the traditional with the genomic information compared to traditional BLUP method indicate that the genomic predictions can be used as a tool to improve the genetic gains and reduce the range of generations. The second article had as its objectives: to determine the mRNA expression of paraoxonases (PON) 1, 2 and 3 in the testicular parenchyma, seminal vesicles, and epididymis of bulls, to evaluate the activity of PON1 in the bloodstream and in seminal plasma; and to correlate that activity with characteristics of breeding soundness. Characterization of gene expression by qRT-PCR and the determination of PON1 activity were performed in serum and seminal plasma from bulls 110. The PON 1, 2 and 3 were expressed in testicular parenchyma of the animals examined. There was a positive correlation between activity and serum PON1 seminal with different breeding soundness estimators.