RESUMO

Testicular degeneration by heat is the leading cause of infertility in bulls. Beef cattle are generally farmed under hot and humid conditions, and consequently, the thermotolerance of each breed must be considered in their natural environment. This study aimed to evaluate the reproductive characteristics of Brahman bulls maintained in the grazing system, with or without shadow availability. Ten Brahman bulls aging between 24 and 30 months were allocated in two different paddocks, with or without shadow availability. The heat tolerance test was performed on three non-consecutive typical summer days. The semen samples were collected at four times points in a 14 days interval. The climate conditions were monitored throughout the experiment; and clinical evaluation, testicular consistence and scrotal circumference were measured before every semen collection. In addition, semen was evaluated regarding volume, aspect, turbulence, motility, straight movement, sperm concentration, and morphological exam. The studied Brahman bulls showed a high thermolysis capacity, high heat tolerance, and no differences in semen quality were observed between groups.

A degeneração testicular causada pelo calor é a principal causa de infertilidade em touros. Bovinos de corte geralmente são criados em condições de calor e umidade, e, consequentemente, a termotolerância de cada raça deve ser considerada em seu ambiente natural. O presente trabalho teve como objetivo avaliar as características reprodutivas de touros da raça Brahman mantidos em sistema de pastejo, com ou sem disponibilidade de sombra. Dez touros Brahman com idades entre 24 e 30 meses foram alocados em dois piquetes diferentes, com ou sem disponibilidade de sombra. O teste de tolerância ao calor foi realizado em três dias típicos de verão não consecutivos. As amostras de sêmen foram coletadas em quatro momentos em intervalos de 14 dias. As condições climáticas foram monitoradas durante todo o período experimental; e a avaliação clínica, consistência testicular e a circunferência escrotal foram avaliadas antes de cada coleta de sêmen. Ainda, o sêmen foi avaliado quanto ao volume, aspecto, turbulência, motilidade, vigor, concentração espermática e exame morfológico. Os touros estudados da raça Brahman apresentaram alta capacidade de termólise, alta tolerância ao calor, e não foram observadas diferenças na qualidade do sêmen entre os grupos.

RESUMO

O exame andrológico de reprodutores suínos tem grande importância no que se refere a características dos animais e qualidade dos ejaculados por esses produzidos. Este exame compreende a avaliação da saúde geral do plantel, com foco principal nas características reprodutivas, sendo indicada a sua realização a cada 30-50 dias. Dentre as avaliações realizadas no exame andrológico, incluem-se a anamnese, o exame físico e o comportamento sexual dos reprodutores. A anamnese é definida como a obtenção do histórico dos animais e de informações sobre as condições de criação dos mesmos. O exame físico consiste na inspeção e palpação de diferentes estruturas, incluindo a avaliação do animal como um todo, de membros locomotores, cascos e órgãos reprodutivos. A avaliação do comportamento sexual dos reprodutores inclui o acompanhamento dos animais no momento da monta no manequim. Vale ressaltar que um único exame andrológico não é suficiente para determinar a capacidade produtiva e fecundante do reprodutor e que a periodicidade da realização das avaliações é o ponto chave para manter a alta qualidade nas centrais de inseminação artificial.(AU)

Breeding soundness is important regarding boar characteristics and quality of their ejaculates. This exam includes herd general health evaluation focusing mainly on reproductive aspects, and it is indicated to perform it every 30-50 days. Breeding soundness evaluation comprises anamnesis, physical exam and boar sexual behavior. Anamnesis is defined as the obtaining history of the animals and information about housing conditions. Physical examination consists in inspection and palpation of different structures, including evaluation of whole animal, legs, feet and reproductive organs. Sexual behavior evaluation includes monitoring the animals at the time they are mounting a collection dummy. It is important to note that a single breeding soundness examination is not sufficient to determine boar productive and reproductive capacity and, the periodicity of the evaluation is the key to maintain high quality in boar studs.(AU)

Assuntos

RESUMO

O exame andrológico de reprodutores suínos tem grande importância no que se refere a características dos animais e qualidade dos ejaculados por esses produzidos. Este exame compreende a avaliação da saúde geral do plantel, com foco principal nas características reprodutivas, sendo indicada a sua realização a cada 30-50 dias. Dentre as avaliações realizadas no exame andrológico, incluem-se a anamnese, o exame físico e o comportamento sexual dos reprodutores. A anamnese é definida como a obtenção do histórico dos animais e de informações sobre as condições de criação dos mesmos. O exame físico consiste na inspeção e palpação de diferentes estruturas, incluindo a avaliação do animal como um todo, de membros locomotores, cascos e órgãos reprodutivos. A avaliação do comportamento sexual dos reprodutores inclui o acompanhamento dos animais no momento da monta no manequim. Vale ressaltar que um único exame andrológico não é suficiente para determinar a capacidade produtiva e fecundante do reprodutor e que a periodicidade da realização das avaliações é o ponto chave para manter a alta qualidade nas centrais de inseminação artificial.

Breeding soundness is important regarding boar characteristics and quality of their ejaculates. This exam includes herd general health evaluation focusing mainly on reproductive aspects, and it is indicated to perform it every 30-50 days. Breeding soundness evaluation comprises anamnesis, physical exam and boar sexual behavior. Anamnesis is defined as the obtaining history of the animals and information about housing conditions. Physical examination consists in inspection and palpation of different structures, including evaluation of whole animal, legs, feet and reproductive organs. Sexual behavior evaluation includes monitoring the animals at the time they are mounting a collection dummy. It is important to note that a single breeding soundness examination is not sufficient to determine boar productive and reproductive capacity and, the periodicity of the evaluation is the key to maintain high quality in boar studs.

Assuntos

RESUMO

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty-six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.

Assuntos

RESUMO

We studied the evolution and the relationship between the fertility of a cow herd and the breeding soundness evaluation (BSE). During four years, 1092 Nellore zebu bulls were maintained on pasture conditions in Mato Grosso do Sul State Brazil. After the clinic evaluation, scrotal circumference was measured and semen was collected by electro ejaculation and analyzed for physical and morphological aspects. Scores for CAP were established by sperm progressive motility (MOT), sperm morphology (MORF), and scrotal circumference (PEP). Modifications to original BSE were established by sperm concentration, sperm motility intensity, and testicles morphology. During the breeding season, 157 bulls were chosen from a-c BSE score. Fifteen reproductive groups of bulls were established randomly among three groups of females (Nellore zebu heifers, first-calf cows, mature cows, and first-calf cross-bred cows). After four years of observations, there was a significant increase in BSE varying, respectively, from 59.5 to 79.0 in 1994 to 1997. The BSE scores PEP, MOT and MORF increased in the period from 17.5, 12.7, and 29.3 to 30.1, 14.8, and 34.4, respectively. Correlations were observed among the BSE components with the year and the studied reproductive characteristics. There was a significant increase of bulls in the BSE categories 'a' and 'b' of 9.0% and 46.9% vs. 43.5% and 44.8%, respectively. The data of 1997 breeding season were: 82.0 ± 13.2 points and 83.1 ± 8.4% for BSE and pregnancy rate, respectively. There was a relationship (P <0.001) between BSE and pregnancy rate (r=0.25). The Breeding Soundness Evaluations (BSE) showed a positive correlation with the pregnancy rate in a herd with different categories of females. The use of 'a' and 'b' BSE bull groups is compatible with the high fertility potential of the herd. The ratio bull:cow used underestimates the reproductive potential of the bulls fertility. [...](AU)

Estudou-se a evolução da capacidade andrológica por pontos (CAP) de 1092 touros Nelore, mantidos a pasto, durante quatro anos, e sua relação com a porcentagem de prenhez após uma estação reprodutiva. A cada ano, realizaram-se avaliações clínico-andrológicas em que mediu-se o perímetro escrotal (PE) e se coleou sêmen por eletroejaculação, para avaliação dos aspectos físicos e morfológicos dos ejaculados. A partir dos pontos obtidos pelo PE (PEP), motilidade progressiva (MOT) e morfologia espermática (MORF), computaram-se os CAP. Na estação de monta foram utilizadas 4319 fêmeas e 256 touros Nelore, em regime de pasto, para avaliação da fertilidade do rebanho. Após a escolha de 157 touros dentro das faixas A-C do CAP, foram estabelecidos, aleatoriamente, 15 grupos de touros para diferentes categorias e quantidade de fêmeas. Nos quatro anos de estudo houve aumento significativo do CAP, de 59,5 a 79,0. A PEP, MOT e MORF aumentaram no mesmo período de 17,5, 12,7 e 29,3 para 30,1, 14,8 e 34,4, respectivamente (P<0,05). Foram observadas correlações entre o CAP com os seus componentes, o ano e as características reprodutivas estudadas. Houve aumento significativo de touros enquadrados nas categorias A e B do CAP de 9,0% e 46,9% vs. 43,5% e 44,8%, respectivamente. O CAP e a porcentagem de prenhez das fêmeas foram de 82,0 ± 13,2 pontos e 83,1 ± 8,4 %, respectivamente. Houve correlação (P<0,001) entre o CAP e a taxa de prenhez (r=0,25). A utilização de grupos de touros das faixas A e B do CAP favoreceu o aumento da percentagem de prenhez no rebanho. A relação touro:fêmea observada sub-utiliza o potencial reprodutivo dos touros. A técnica empregada foi importante para avaliar a fertilidade potencial e modificar as características reprodutivas da população de touros estudada.(AU)

Assuntos

RESUMO

Abstract We studied the evolution and the relationship between the fertility of a cow herd and the breeding soundness evaluation (BSE). During four years, 1092 Nellore zebu bulls were maintained on pasture conditions in Mato Grosso do Sul State - Brazil. After the clinic evaluation, scrotal circumference was measured and semen was collected by electro ejaculation and analyzed for physical and morphological aspects. Scores for CAP were established by sperm progressive motility (MOT), sperm morphology (MORF), and scrotal circumference (PEP). Modifications to original BSE were established by sperm concentration, sperm motility intensity, and testicles morphology. During the breeding season, 157 bulls were chosen from a-c BSE score. Fifteen reproductive groups of bulls were established randomly among three groups of females (Nellore zebu heifers, first-calf cows, mature cows, and first-calf cross-bred cows). After four years of observations, there was a significant increase in BSE varying, respectively, from 59.5 to 79.0 in 1994 to 1997. The BSE scores PEP, MOT and MORF increased in the period from 17.5, 12.7, and 29.3 to 30.1, 14.8, and 34.4, respectively. Correlations were observed among the BSE components with the year and the studied reproductive characteristics. There was a significant increase of bulls in the BSE categories 'a' and 'b' of 9.0% and 46.9% vs. 43.5% and 44.8%, respectively. The data of 1997 breeding season were: 82.0 ± 13.2 points and 83.1 ± 8.4% for BSE and pregnancy rate, respectively. There was a relationship (P 0.001) between BSE and pregnancy rate (r=0.25). The Breeding Soundness Evaluations (BSE) showed a positive correlation with the pregnancy rate in a herd with different categories of females. The use of 'a' and 'b' BSE bull groups is compatible with the high fertility potential of the herd. The ratio bull:cow used underestimates the reproductive potential of the bulls' fertility. The technique used was important to evaluate the group potential fertility and to modify the reproductive characteristics of bulls herd.

Resumo Estudou-se a evolução da capacidade andrológica por pontos (CAP) de 1092 touros Nelore, mantidos a pasto, durante quatro anos, e sua relação com a porcentagem de prenhez após uma estação reprodutiva. A cada ano, realizaram-se avaliações clínico-andrológicas em que mediu-se o perímetro escrotal (PE) e se coleou sêmen por eletroejaculação, para avaliação dos aspectos físicos e morfológicos dos ejaculados. A partir dos pontos obtidos pelo PE (PEP), motilidade progressiva (MOT) e morfologia espermática (MORF), computaram-se os CAP. Na estação de monta foram utilizadas 4319 fêmeas e 256 touros Nelore, em regime de pasto, para avaliação da fertilidade do rebanho. Após a escolha de 157 touros dentro das faixas A-C do CAP, foram estabelecidos, aleatoriamente, 15 grupos de touros para diferentes categorias e quantidade de fêmeas. Nos quatro anos de estudo houve aumento significativo do CAP, de 59,5 a 79,0. A PEP, MOT e MORF aumentaram no mesmo período de 17,5, 12,7 e 29,3 para 30,1, 14,8 e 34,4, respectivamente (P 0,05). Foram observadas correlações entre o CAP com os seus componentes, o ano e as características reprodutivas estudadas. Houve aumento significativo de touros enquadrados nas categorias A e B do CAP de 9,0% e 46,9% vs. 43,5% e 44,8%, respectivamente. O CAP e a porcentagem de prenhez das fêmeas foram de 82,0 ± 13,2 pontos e 83,1 ± 8,4 %, respectivamente. Houve correlação (P 0,001) entre o CAP e a taxa de prenhez (r=0,25). A utilização de grupos de touros das faixas A e B do CAP favoreceu o aumento da percentagem de prenhez no rebanho. A relação touro:fêmea observada sub-utiliza o potencial reprodutivo dos touros. A técnica empregada foi importante para avaliar a fertilidade potencial e modificar as características reprodutivas da população de touros estudada.

RESUMO

We studied the evolution and the relationship between the fertility of a cow herd and the breeding soundness evaluation (BSE). During four years, 1092 Nellore zebu bulls were maintained on pasture conditions in Mato Grosso do Sul State – Brazil. After the clinic evaluation, scrotal circumference was measured and semen was collected by electro ejaculation and analyzed for physical and morphological aspects. Scores for CAP were established by sperm progressive motility (MOT), sperm morphology (MORF), and scrotal circumference (PEP). Modifications to original BSE were established by sperm concentration, sperm motility intensity, and testicles morphology. During the breeding season, 157 bulls were chosen from a-c BSE score. Fifteen reproductive groups of bulls were established randomly among three groups of females (Nellore zebu heifers, first-calf cows, mature cows, and first-calf cross-bred cows). After four years of observations, there was a significant increase in BSE varying, respectively, from 59.5 to 79.0 in 1994 to 1997. The BSE scores PEP, MOT and MORF increased in the period from 17.5, 12.7, and 29.3 to 30.1, 14.8, and 34.4, respectively. Correlations were observed among the BSE components with the year and the studied reproductive characteristics. There was a significant increase of bulls in the BSE categories 'a' and 'b' of 9.0% and 46.9% vs. 43.5% and 44.8%, respectively. The data of 1997 breeding season were: 82.0 ± 13.2 points and 83.1 ± 8.4% for BSE and pregnancy rate, respectively. There was a relationship (P <0.001) between BSE and pregnancy rate (r=0.25). The Breeding Soundness Evaluations (BSE) showed a positive correlation with the pregnancy rate in a herd with different categories of females. The use of 'a' and 'b' BSE bull groups is compatible with the high fertility potential of the herd. The ratio bull:cow used underestimates the reproductive potential of the bulls’ fertility. [...]

Estudou-se a evolução da capacidade andrológica por pontos (CAP) de 1092 touros Nelore, mantidos a pasto, durante quatro anos, e sua relação com a porcentagem de prenhez após uma estação reprodutiva. A cada ano, realizaram-se avaliações clínico-andrológicas em que mediu-se o perímetro escrotal (PE) e se coleou sêmen por eletroejaculação, para avaliação dos aspectos físicos e morfológicos dos ejaculados. A partir dos pontos obtidos pelo PE (PEP), motilidade progressiva (MOT) e morfologia espermática (MORF), computaram-se os CAP. Na estação de monta foram utilizadas 4319 fêmeas e 256 touros Nelore, em regime de pasto, para avaliação da fertilidade do rebanho. Após a escolha de 157 touros dentro das faixas A-C do CAP, foram estabelecidos, aleatoriamente, 15 grupos de touros para diferentes categorias e quantidade de fêmeas. Nos quatro anos de estudo houve aumento significativo do CAP, de 59,5 a 79,0. A PEP, MOT e MORF aumentaram no mesmo período de 17,5, 12,7 e 29,3 para 30,1, 14,8 e 34,4, respectivamente (P<0,05). Foram observadas correlações entre o CAP com os seus componentes, o ano e as características reprodutivas estudadas. Houve aumento significativo de touros enquadrados nas categorias A e B do CAP de 9,0% e 46,9% vs. 43,5% e 44,8%, respectivamente. O CAP e a porcentagem de prenhez das fêmeas foram de 82,0 ± 13,2 pontos e 83,1 ± 8,4 %, respectivamente. Houve correlação (P<0,001) entre o CAP e a taxa de prenhez (r=0,25). A utilização de grupos de touros das faixas A e B do CAP favoreceu o aumento da percentagem de prenhez no rebanho. A relação touro:fêmea observada sub-utiliza o potencial reprodutivo dos touros. A técnica empregada foi importante para avaliar a fertilidade potencial e modificar as características reprodutivas da população de touros estudada.

Assuntos

RESUMO

Background: Ultrasound images depend on the relative density of the tissues to be examined. During the period of sexual maturity, the cellular content and changes in the secretion of liquids from the genital organs assist in the identification of development changes. However, the establishment of normal ultrasound parameters for testicular dimensions and the characterization of normal testicular images are necessary to permit more detailed studies related to degenerative and pathological conditions of bovine testes. The objective of this study was to evaluate the pattern of echogenicity of the testicular parenchyma in young Nellore bulls at different stages of sexual maturity. Materials, Methods & Results: The sample consisted of 405 young Nellore bulls between 21 and 33 months of age. All of the animals were evaluated for breeding soundness examination and ultrasound examination of the testes. All of the images were transferred to the computer with the help of Image J software for further analysis. To correlate the several intensities of pixel resolutions with sexual maturity stage and to study the pattern of testicular parenchyma echogenicity of the animals, the bulls were subdivided in three age classes: 1) 21 to 25.9 months, 2) 26 to 29.9 months, and 3) 30 to 33 months. Additionally, according to the physical and morphological semen features, the animals were classified

Background: Ultrasound images depend on the relative density of the tissues to be examined. During the period of sexual maturity, the cellular content and changes in the secretion of liquids from the genital organs assist in the identification of development changes. However, the establishment of normal ultrasound parameters for testicular dimensions and the characterization of normal testicular images are necessary to permit more detailed studies related to degenerative and pathological conditions of bovine testes. The objective of this study was to evaluate the pattern of echogenicity of the testicular parenchyma in young Nellore bulls at different stages of sexual maturity. Materials, Methods & Results: The sample consisted of 405 young Nellore bulls between 21 and 33 months of age. All of the animals were evaluated for breeding soundness examination and ultrasound examination of the testes. All of the images were transferred to the computer with the help of Image J software for further analysis. To correlate the several intensities of pixel resolutions with sexual maturity stage and to study the pattern of testicular parenchyma echogenicity of the animals, the bulls were subdivided in three age classes: 1) 21 to 25.9 months, 2) 26 to 29.9 months, and 3) 30 to 33 months. Additionally, according to the physical and morphological semen features, the animals were classified

RESUMO

Background: Ultrasound images depend on the relative density of the tissues to be examined. During the period of sexual maturity, the cellular content and changes in the secretion of liquids from the genital organs assist in the identification of development changes. However, the establishment of normal ultrasound parameters for testicular dimensions and the characterization of normal testicular images are necessary to permit more detailed studies related to degenerative and pathological conditions of bovine testes. The objective of this study was to evaluate the pattern of echogenicity of the testicular parenchyma in young Nellore bulls at different stages of sexual maturity. Materials, Methods & Results: The sample consisted of 405 young Nellore bulls between 21 and 33 months of age. All of the animals were evaluated for breeding soundness examination and ultrasound examination of the testes. All of the images were transferred to the computer with the help of Image J software for further analysis. To correlate the several intensities of pixel resolutions with sexual maturity stage and to study the pattern of testicular parenchyma echogenicity of the animals, the bulls were subdivided in three age classes: 1) 21 to 25.9 months, 2) 26 to 29.9 months, and 3) 30 to 33 months. Additionally, according to the physical and morphological semen features, the animals were classified

Background: Ultrasound images depend on the relative density of the tissues to be examined. During the period of sexual maturity, the cellular content and changes in the secretion of liquids from the genital organs assist in the identification of development changes. However, the establishment of normal ultrasound parameters for testicular dimensions and the characterization of normal testicular images are necessary to permit more detailed studies related to degenerative and pathological conditions of bovine testes. The objective of this study was to evaluate the pattern of echogenicity of the testicular parenchyma in young Nellore bulls at different stages of sexual maturity. Materials, Methods & Results: The sample consisted of 405 young Nellore bulls between 21 and 33 months of age. All of the animals were evaluated for breeding soundness examination and ultrasound examination of the testes. All of the images were transferred to the computer with the help of Image J software for further analysis. To correlate the several intensities of pixel resolutions with sexual maturity stage and to study the pattern of testicular parenchyma echogenicity of the animals, the bulls were subdivided in three age classes: 1) 21 to 25.9 months, 2) 26 to 29.9 months, and 3) 30 to 33 months. Additionally, according to the physical and morphological semen features, the animals were classified

RESUMO

Background: Ultrasound images depend on the relative density of the tissues to be examined. During the period of sexual maturity, the cellular content and changes in the secretion of liquids from the genital organs assist in the identification of development changes. However, the establishment of normal ultrasound parameters for testicular dimensions and the characterization of normal testicular images are necessary to permit more detailed studies related to degenerative and pathological conditions of bovine testes. The objective of this study was to evaluate the pattern of echogenicity of the testicular parenchyma in young Nellore bulls at different stages of sexual maturity. Materials, Methods & Results: The sample consisted of 405 young Nellore bulls between 21 and 33 months of age. All of the animals were evaluated for breeding soundness examination and ultrasound examination of the testes. All of the images were transferred to the computer with the help of Image J software for further analysis. To correlate the several intensities of pixel resolutions with sexual maturity stage and to study the pattern of testicular parenchyma echogenicity of the animals, the bulls were subdivided in three age classes: 1) 21 to 25.9 months, 2) 26 to 29.9 months, and 3) 30 to 33 months. Additionally, according to the physical and morphological semen features, the animals were classified into the following five breeding soundness classes: 1= animals sound for breeding; 2= animals sound for breeding in a natural mating system; 3= animals temporarily unsound for breeding; 4= animals excluded due to imperfect spermiogenesis; 5= animals excluded on the basis of genital morphological abnormalities. SAEG software version 9.1 was used to perform the statistical analyses. There was no difference between the mean pixel intensity values (103.8, 105.1, 103.9 and 102.0 for classes 1, 2, 3 and 4, respectively) or in relation to the age within the same breeding soundness class (P > 0.05). There were no differences in the average pixel intensity values between the breeding soundness classes or age classes (P > 0.05). These results indicate that the breeding ability and age were not refl ected by the testicular echotexture in the group of evaluated animals. There was a slight correlation between the PI of the testicular regions with the SC (r = 0.11, 0.12 and 0.13 for the LT, RT and LRT, respectively) and the TV (r = 0.11, 0.12 and 0.13 for the LT, RT and LRT, respectively). No other correlations were found between the studied characteristics and the PI values of the studied images (P > 0.05). Discussion: In the current study, the animals were in the growth phase near or at the end phase of the establishment of sexual maturity, and the volume of the seminiferous tubules would have already increased. The structure of the seminiferous epithelium most likely did not differ between the breeding soundness classes. Instead, the different classes are due to the spermiogenesis process or spermatic cell metamorphosis. Therefore, the testicular echotexture would not be expected to show a difference among the breeding soundness classes. There was a low correlation between the scrotal circumference and testicular volume and the pixel intensity of the testicular images. Therefore, these results indicate that testicular echotexture evaluation does not allow the prediction of the sexual maturity stage in young bulls.

Assuntos

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Foram obtidas estimativas de variância fenotípica, genética e residual, herdabilidades e correlações genéticas para as características reprodutivas em 5.903 animais da raça Nelore. O modelo experimental utilizado foi o método de máxima verossimilhança restrita livre de derivadas. Os valores de herdabilidade foram de 0,24±0,05 para perímetro escrotal aos 450 dias de idade e de 0,37±0,05 aos 21 meses de idade, na ocasião do exame andrológico; de 0,24±0,05 e 0,26±0,05 para comprimento dos testículos esquerdo e direito; de 0,29±0,05 e 0,31±0,05 para largura dos testículos esquerdo e direito; de 0,12±0,04 para formato testicular; de 0,33±0,06 para volume testicular; de 0,11±0,03 para turbilhonamento; de 0,08±0,03 para motilidade e de 0,05±0,02 para vigor espermático; de 0,20±0,04, 0,03±0,02 e 0,19±0,04 para defeitos espermáticos maiores, menores e totais, respectivamente. As características biométricas testiculares apresentaram valores de herdabilidade moderados a altos, enquanto as características seminais valores baixos. Correlações genéticas entre perímetro escrotal com todas as características reprodutivas foram favoráveis, o que sugere o perímetro escrotal como característica de escolha na seleção de touros.

Estimates of phenotypic, genetics and residual variances for reproductive traits in 5903 Nellore bulls were obtained. The experimental model used was multiple trait derivative-free restricted maximum likelihood. The values obtained for heritability were 0.24±0.05 for scrotal circumference at 450 days of age and 0.37±0.05 at 21 months for age at the time of the breeding soundness evaluation; 0.24±0.05 and 0.26±0.05 for left and right testicle length; 0.29±0.05 and 0.31±0.05 for left and right testicle width; 0.12±0.04 for testicle format; 0.33±0.06 for testicle volume; 0.11±0.03 for gross motility; 0.08±0.03 for individual motility and 0.05±0.02 for spermatic vigor; 0.20±0.04, 0.03±0.02 and 0.19±0.04 for larger defects, smaller defects and total defects, respectively. The values for heritability for testicular biometric characteristics were moderate to high while the seminal characteristics, presented low values. Genetic correlations between scrotal circumference with all the reproductive traits were favorable, suggesting the scrotal circumference as a feature of choice in the selection of bulls.

Assuntos

RESUMO

Foram obtidas estimativas de variância fenotípica, genética e residual, herdabilidades e correlações genéticas para as características reprodutivas em 5.903 animais da raça Nelore. O modelo experimental utilizado foi o método de máxima verossimilhança restrita livre de derivadas. Os valores de herdabilidade foram de 0,24±0,05 para perímetro escrotal aos 450 dias de idade e de 0,37±0,05 aos 21 meses de idade, na ocasião do exame andrológico; de 0,24±0,05 e 0,26±0,05 para comprimento dos testículos esquerdo e direito; de 0,29±0,05 e 0,31±0,05 para largura dos testículos esquerdo e direito; de 0,12±0,04 para formato testicular; de 0,33±0,06 para volume testicular; de 0,11±0,03 para turbilhonamento; de 0,08±0,03 para motilidade e de 0,05±0,02 para vigor espermático; de 0,20±0,04, 0,03±0,02 e 0,19±0,04 para defeitos espermáticos maiores, menores e totais, respectivamente. As características biométricas testiculares apresentaram valores de herdabilidade moderados a altos, enquanto as características seminais valores baixos. Correlações genéticas entre perímetro escrotal com todas as características reprodutivas foram favoráveis, o que sugere o perímetro escrotal como característica de escolha na seleção de touros.(AU)

Estimates of phenotypic, genetics and residual variances for reproductive traits in 5903 Nellore bulls were obtained. The experimental model used was multiple trait derivative-free restricted maximum likelihood. The values obtained for heritability were 0.24±0.05 for scrotal circumference at 450 days of age and 0.37±0.05 at 21 months for age at the time of the breeding soundness evaluation; 0.24±0.05 and 0.26±0.05 for left and right testicle length; 0.29±0.05 and 0.31±0.05 for left and right testicle width; 0.12±0.04 for testicle format; 0.33±0.06 for testicle volume; 0.11±0.03 for gross motility; 0.08±0.03 for individual motility and 0.05±0.02 for spermatic vigor; 0.20±0.04, 0.03±0.02 and 0.19±0.04 for larger defects, smaller defects and total defects, respectively. The values for heritability for testicular biometric characteristics were moderate to high while the seminal characteristics, presented low values. Genetic correlations between scrotal circumference with all the reproductive traits were favorable, suggesting the scrotal circumference as a feature of choice in the selection of bulls.(AU)

Assuntos

RESUMO

O objetivo deste trabalho foi revisar, apresentar e discutir aspectos relacionados à avaliação da morfologia espermática no exame clínico andrológico de rotina de touros. Neste tipo de avaliação, de touros na monta natural, a morfologia espermática foi considerada como o aspecto isolado que mais se relacionava com a fertilidade no rebanho. Também adquire importância para caracterizar, de forma prática, a idade da maturidade sexual de um touro. Com respeito às metodologias de avaliação dos diferentes defeitos espermáticos, recomenda-se priorizar a preparação em lâmina úmida em microscopia de contraste de fase pela melhor observação de defeitos considerados importantes para o prognóstico e ou daqueles relacionados com a fertilização e formação do embrião. A classificação de defeitos compensáveis e não compensáveis tem registrado avanços significativos na sua compreensão com novas tecnologias e pesquisas. Neste aspecto, os defeitos de cabeça espermática, com pequenas modificações na forma (cabeça sutilmente ou levemente deformada), deveriam ser considerados com maior atenção na avaliação do espermiograma.(AU)

The purpose of this review was to present and discuss aspects related to the evaluation of sperm morphology in the Breeding Soundness Examination routine of bulls. In this type of evaluation of bulls in natural breeding, the sperm morphology was considered the single aspect that is most related to fertility in cattle. It also acquires importance as a practical way to characterize the age of sexual maturity of a bull and therefore precocity. In respect to methods of assessing the different sperm defects, it is recommended to prioritize the preparation phase-contrast microscopy of wet-mount semen for more accurate evaluation of sperm defect, related to fertilization, embryo formation and prognosis of individual bulls. The compensable and non compensable sperm characteristics and classification have been significant advances in the understanding of new technologies and researches. In this respect, the sperm head defects with subtly shape changes should be considered more carefully in the sperm morphology examination.(AU)

Assuntos

RESUMO

T he aim of this study was to evaluate the rejection rates of bulls in the behavioral assessment (libido and mounting capacity) and the importance of this step in the breeding soundness evaluation of 30, 700 beef bulls i n the state of Rio Grande do Sul, Brazil. Bulls from the following breeds were evaluated: Aberdeen Angus, Red Angus, Hereford, Polled Hereford, Devon, Shorthorn, Brangus, Braford, Montana, Santa Gertrudis, Charolais, Limousin, Brahman, Nelore, and Tabapua. In order to investigate the relationship between the binary variable ( approved or rejected in different steps of the breeding soundness evaluation) and age groups (young and mature bulls), the Chi - Square test (PROC - FREQ) and the Tukey test were used. The general rejection rates in the breeding soundne ss evaluation were 13.7 and 22.7 % for young and mature bulls, respectively. In the present study, problems in the sexual behavior of bulls accounted for the rejection of 3. 6 to 5.2% of young and mature bulls, respectively . Lack of libido and / or mounting capacity were shown to be importan t problems in relation to the total number of possible causes of rejection of bulls in the breeding soundness evaluation. Several factors may affect the expression of libido and / or mounting capacity at pasture , and the conditions under which this step is carried out may influence the results. P erform ing behavioral assessment as part of the breeding soundness evaluatio n has been shown to be important to the thorough reproductive e valuation of bulls. The rejection of bulls i n the behavioral assessment may suggest that this step should be performed regularly , rather than just being complementary to the standard breeding soundness evaluation.(AU)

Assuntos

RESUMO

T he aim of this study was to evaluate the rejection rates of bulls in the behavioral assessment (libido and mounting capacity) and the importance of this step in the breeding soundness evaluation of 30, 700 beef bulls i n the state of Rio Grande do Sul, Brazil. Bulls from the following breeds were evaluated: Aberdeen Angus, Red Angus, Hereford, Polled Hereford, Devon, Shorthorn, Brangus, Braford, Montana, Santa Gertrudis, Charolais, Limousin, Brahman, Nelore, and Tabapua. In order to investigate the relationship between the binary variable ( approved or rejected in different steps of the breeding soundness evaluation) and age groups (young and mature bulls), the Chi - Square test (PROC - FREQ) and the Tukey test were used. The general rejection rates in the breeding soundne ss evaluation were 13.7 and 22.7 % for young and mature bulls, respectively. In the present study, problems in the sexual behavior of bulls accounted for the rejection of 3. 6 to 5.2% of young and mature bulls, respectively . Lack of libido and / or mounting capacity were shown to be importan t problems in relation to the total number of possible causes of rejection of bulls in the breeding soundness evaluation. Several factors may affect the expression of libido and / or mounting capacity at pasture , and the conditions under which this step is carried out may influence the results. P erform ing behavioral assessment as part of the breeding soundness evaluatio n has been shown to be important to the thorough reproductive e valuation of bulls. The rejection of bulls i n the behavioral assessment may suggest that this step should be performed regularly , rather than just being complementary to the standard breeding soundness evaluation.

Assuntos

RESUMO

O objetivo deste trabalho foi revisar, apresentar e discutir aspectos relacionados à avaliação da morfologia espermática no exame clínico andrológico de rotina de touros. Neste tipo de avaliação, de touros na monta natural, a morfologia espermática foi considerada como o aspecto isolado que mais se relacionava com a fertilidade no rebanho. Também adquire importância para caracterizar, de forma prática, a idade da maturidade sexual de um touro. Com respeito às metodologias de avaliação dos diferentes defeitos espermáticos, recomenda-se priorizar a preparação em lâmina úmida em microscopia de contraste de fase pela melhor observação de defeitos considerados importantes para o prognóstico e ou daqueles relacionados com a fertilização e formação do embrião. A classificação de defeitos compensáveis e não compensáveis tem registrado avanços significativos na sua compreensão com novas tecnologias e pesquisas. Neste aspecto, os defeitos de cabeça espermática, com pequenas modificações na forma (cabeça sutilmente ou levemente deformada), deveriam ser considerados com maior atenção na avaliação do espermiograma.

The purpose of this review was to present and discuss aspects related to the evaluation of sperm morphology in the Breeding Soundness Examination routine of bulls. In this type of evaluation of bulls in natural breeding, the sperm morphology was considered the single aspect that is most related to fertility in cattle. It also acquires importance as a practical way to characterize the age of sexual maturity of a bull and therefore precocity. In respect to methods of assessing the different sperm defects, it is recommended to prioritize the preparation phase-contrast microscopy of wet-mount semen for more accurate evaluation of sperm defect, related to fertilization, embryo formation and prognosis of individual bulls. The compensable and non compensable sperm characteristics and classification have been significant advances in the understanding of new technologies and researches. In this respect, the sperm head defects with subtly shape changes should be considered more carefully in the sperm morphology examination.

Assuntos

RESUMO

There is a single set of standard for breeding soundness evaluation in bulls for ali breeds and production systems, resulting in economical losses due to high frequencies of culling in bulls of some genotypes. This study presents an analysis on two sets of field data, comparing contemporary groups of bulls from taurine pure-breds and zebu crossbreeds. The results were indicative that more flexible standards could be useful, avoiding injustified culling of bulls. This fact may be justified by the absence of interaction between breed and reproductive condition. It will be importam to continue the studies on procedures and standards for breeding soundness evaluation in bulls, to reduce losses in the production systems due to peculiarities inherent to the genetic groups.

Os padrões recomendados para os componentes do exame andrológico são únicos para todas as raças e sistemas de produção, resultando em perdas económicas pela eliminação de reprodutores em alguns conjuntos raciais. O presente estudo apresenta uma análise retrospectiva sobre dois conjuntos de dados de campo, comparando grupos contemporâneos de touros de raças puras taurinas e derivadas de cruzamento com zebuínos. Os resultados indicam que o uso de padrões mais flexíveis resultam em um comportamento semelhante dos distintos grupos raciais, quanto à condição reprodutiva, em contraste com os critérios atuais que classificam de maneira diferente animais de distintos genótipos taurinos puros e seu cruzamento com zebuínos. É enfatizada a importância de estudos sobre os critérios recomendados para a classificação reprodutiva de touros, no sentido de reduzir perdas impostas aos sistemas de produção em decorrência de peculiaridades inerentes a grupos genéticos diferenciados.

RESUMO

There is a single set of standard for breeding soundness evaluation in bulls for ali breeds and production systems, resulting in economical losses due to high frequencies of culling in bulls of some genotypes. This study presents an analysis on two sets of field data, comparing contemporary groups of bulls from taurine pure-breds and zebu crossbreeds. The results were indicative that more flexible standards could be useful, avoiding injustified culling of bulls. This fact may be justified by the absence of interaction between breed and reproductive condition. It will be importam to continue the studies on procedures and standards for breeding soundness evaluation in bulls, to reduce losses in the production systems due to peculiarities inherent to the genetic groups.

Os padrões recomendados para os componentes do exame andrológico são únicos para todas as raças e sistemas de produção, resultando em perdas económicas pela eliminação de reprodutores em alguns conjuntos raciais. O presente estudo apresenta uma análise retrospectiva sobre dois conjuntos de dados de campo, comparando grupos contemporâneos de touros de raças puras taurinas e derivadas de cruzamento com zebuínos. Os resultados indicam que o uso de padrões mais flexíveis resultam em um comportamento semelhante dos distintos grupos raciais, quanto à condição reprodutiva, em contraste com os critérios atuais que classificam de maneira diferente animais de distintos genótipos taurinos puros e seu cruzamento com zebuínos. É enfatizada a importância de estudos sobre os critérios recomendados para a classificação reprodutiva de touros, no sentido de reduzir perdas impostas aos sistemas de produção em decorrência de peculiaridades inerentes a grupos genéticos diferenciados.