Cryopreservation of Piau-Breed Wild Boar Sperm: Assessment of Cooling Curves and Centrifugation Regimes.

This study aimed to assess the effects of different cooling curves and centrifugation regimes used in cryopreservation protocols on the post-thaw viability of Piau-breed wild boar (Sus scrofa) sperm using in vitro assessment tests. Two centrifugations (800 g for 10 min and 2400 g for 3 min) and two cooling curves (conventional cooling using nitrogen vapour - freezing 1 and automated cooling using a programmed freezing machine - freezing 2) were tested. Therefore, the treatments were divided into M3 - centrifugation at 2400 g for 3 min and freezing 2; M10 - centrifugation at 800 g for 10 min and freezing 2; R3 - centrifugation at 2400 g for 3 min and freezing 1; and R10 - centrifugation at 800 g for 10 min and freezing 1. No significant differences (p > 0.05) between treatments occurred post-thawing regarding the total sperm motility means recorded. The mean values of the different treatments were not different from each other regarding the supravital staining (SV), hypo-osmotic test (HO), sperm-egg binding assay or sperm morphology. This study showed that both the cooling curve and the centrifugation regime affected the quality of post-thaw sperm, and centrifugation for shorter times and cooling curves using automated cooling are the most suitable for minimizing sperm injury.

Sexual precocity of Nellore bulls that are offspring of super precocious, precocious and normal cows in extensive farming conditions.

The objective of this work was to verify that mothers classified as super precocious (M1) and precocious (M2) produce more precocious bulls than females classified as normal (M3). This study included 21,186 animals with an average age of 21.29 ± 1.77 months that underwent a breeding soundness evaluation from 1999 to 2008. Of these animals, 2019, 6059 and 13,108 were offspring of M1, M2 and M3 females, respectively. In the breeding soundness examination, the animals were classified as sound for reproduction, sound under a natural mating regime, unsound for reproduction and discarded. To compare the averages obtained for each category of mother within the individual breeding soundness classes, a chi-square test with a 5% error probability was used, considering the effects of year and month of birth and farm. For the three classes of mothers (M1, M2 and M3), 67.26, 67.22 and 64.16% of bull calves were considered sound for reproduction and 19.71, 19.46 and 21.90% were considered unsound for reproduction, respectively. There was no difference in the frequency of animals that were sound for reproduction under the natural breeding regime between the three classes of mothers (8.87, 9.31 and 9.19%, respectively). There was a difference between the numbers of precocious and normal females that were discarded, with frequencies of 4.01 and 4.75%, respectively (p < 0.05). There were differences in year and month of birth and farm between super precocious and precocious cows in relation to the breeding soundness classification of the animals. It was concluded that the bull offspring of super precocious and precocious cows presented a higher percentage of approval in the breeding soundness examination than the bull offspring of normal cows, demonstrating that the selection for precocity of females has contributed to an increase in the sexual precocity of the herd in relation to the sexual maturity of bulls.

Radon dose assessment in underground mines in Brazil.

Underground miners are internally exposed to radon, thoron and their short-lived decay products during the mineral processing. There is also an external exposure due to the gamma emitters present in the rock and dust of the mine. However, the short-lived radon decay products are recognised as the main radiation health risk. When inhaled, they are deposited in the respiratory system and may cause lung cancer. To address this concern, concentration measurements of radon and its progeny were performed, the equilibrium factor was determined and the effective dose received was estimated in six Brazilian underground mines. The radon concentration was measured by using E-PERM, AlphaGUARD and CR-39 detectors. The radon progeny was determined by using DOSEman. The annual effective dose for the miners was estimated according to United Nations Scientific Committee on the Effects of Atomic Radiation methodologies. The mean value of the equilibrium factor was 0.4. The workers' estimated effective dose ranged from 1 to 21 mSv a(-1) (mean 9 mSv a(-1)).

Follicular dynamics and gene expression in granulosa cells, corpora lutea and oocytes from gilts of breeds with low and high ovulation rates.

Follicular dynamics and the expression of candidate genes using real-time polymerase chain reaction (PCR) were compared during the oestrous cycle of pig breeds with high (commercial line; n=24) and low (local Brazilian Piau; n=21) ovulation rates and prolificacy. Gilts were killed on Days 0, 4, 10 and 18 of the oestrous cycle and visible ovarian follicles were classified by follicular diameter. Recovered cumulus-oocyte complexes were classified as normal or atretic and frozen in liquid nitrogen until RNA extraction. Low ovulation rates and/or prolificacy in Piau gilts was associated with a different pattern of follicle development, with lower numbers of small follicles on Day 18, fewer large follicles on Days 0 and 18 (P≤0.05) and a higher proportion of atretic follicles on Days 0 and 18 (P≤0.05). Compared with commercial line gilts, less-prolific Piau gilts exhibited higher expression of apoptotic genes during luteolysis (CASP3 and FASL; P≤0.05), decreased expression of TGFBR2 and BAX mRNA in the corpus luteum (P≤0.05), higher expression of apoptotic genes (FAS, BCL2 and CASP8; P≤0.05) in granulosa cells and a greater abundance (P≤0.05) of genes controlling oocyte-secreted factors (GDF9, BMP15 and BMP6), suggesting underlying mechanisms controlling differences in follicular development, ovulation rate and inherent prolificacy in this pig breed.

Assessment of different solutions and incubation times in the hypoosmotic swelling test of frozen/thawed semen in Piau boars

The objective of this study was to assess the effect of several solutions and incubation times in the hypoosmotic swelling test in predicting the in vitro quality of the frozen/thawed semen of Piau boars. Four samples of frozen semen from five different Piau boars were used. For the assessment of the hypoosmotic test, three incubation times were used (5, 30 and 60 min) in three different hypoosmotic solutions (BTS at 75 mOsm/Kg, sucrrose at 100 mOsm/Kg and fructose and sodium citrate at 100 mOsm/Kg), thus, samples were submitted to each hypoosmotic solution in three incubation times. The means of sperm motility spermatic vigor and live sperm by supravital staining for the assessed samples were respectively, 37.5 ± 7.2%, 2.8 ± 0.3 and 37.4 ± 7.8% in thawing and 15.5 ± 7.6%, 1.7 ± 0.5 and 22.6 ± 6.6% after 120 mm of thermoresistance test (P < 0.05). There was no difference between the mean values obtained for reactive sperm in the different incubation times and hypoosmotic solutions, and also no interaction between time ans solutions. The results obtained in the resent study demonstrated that quality of frozen/thawed semen, besides offering aliernatives for hypoosmotic solutions and different incubation times in performing the hypoosmotic test to predict the sperm plasmatic membrane quality in boats.

Assessment of different solutions and incubation times in the hypoosmotic swelling test of frozen/thawed semen in Piau boars

The objective of this study was to assess the effect of several solutions and incubation times in the hypoosmotic swelling test in predicting the in vitro quality of the frozen/thawed semen of Piau boars. Four samples of frozen semen from five different Piau boars were used. For the assessment of the hypoosmotic test, three incubation times were used (5, 30 and 60 min) in three different hypoosmotic solutions (BTS at 75 mOsm/Kg, sucrrose at 100 mOsm/Kg and fructose and sodium citrate at 100 mOsm/Kg), thus, samples were submitted to each hypoosmotic solution in three incubation times. The means of sperm motility spermatic vigor and live sperm by supravital staining for the assessed samples were respectively, 37.5 ± 7.2%, 2.8 ± 0.3 and 37.4 ± 7.8% in thawing and 15.5 ± 7.6%, 1.7 ± 0.5 and 22.6 ± 6.6% after 120 mm of thermoresistance test (P < 0.05). There was no difference between the mean values obtained for reactive sperm in the different incubation times and hypoosmotic solutions, and also no interaction between time ans solutions. The results obtained in the resent study demonstrated that quality of frozen/thawed semen, besides offering aliernatives for hypoosmotic solutions and different incubation times in performing the hypoosmotic test to predict the sperm plasmatic membrane quality in boats.(AU)

Hypoosmotic swelling test in young Nelore bulls classified as sound and unsound for breeding

This work aimed to study the correlations between the physical characteristics of semen, sperm morphology and the biochemical integrity of the plasmatic membrane of raw sperm in young Nelore bulls (Bos taurus indicus). A total of 420 bulls between 18 and 22 months of age were examined for breeding soundness according to the criteria established by the Brazilian College of Animal Reproduction. After physical and morphological evaluation, semen was tested with a hypoosmotic test. To accomplish this, 10 µl of fresh semen was incubated in 1 ml of hypoosmotic solution (150 mOsm/kg) for 60 min at 37°C. After the breeding soundness evaluation, 83% (350/420) of the bulls were classified as sound for breeding. There were no significant differences between the mean testicular biometry, scrotal circumference and the percentage of spermatozoa reactive to the hypoosmotic test (43.9 ± 21.1% vs. 43.6 ± 19.3%) in bulls classified as sound and unsound for breeding (P > 0.05), although there were significant differences between the averages for all physical and morphological aspects of the sperm between the two groups (P 0.05). In this study, the hypoosmotic test was not an efficient predictor of the reproductive potential of young Nelore bulls.

Hypoosmotic swelling test in young Nelore bulls classified as sound and unsound for breeding

This work aimed to study the correlations between the physical characteristics of semen, sperm morphology and the biochemical integrity of the plasmatic membrane of raw sperm in young Nelore bulls (Bos taurus indicus). A total of 420 bulls between 18 and 22 months of age were examined for breeding soundness according to the criteria established by the Brazilian College of Animal Reproduction. After physical and morphological evaluation, semen was tested with a hypoosmotic test. To accomplish this, 10 µl of fresh semen was incubated in 1 ml of hypoosmotic solution (150 mOsm/kg) for 60 min at 37°C. After the breeding soundness evaluation, 83% (350/420) of the bulls were classified as sound for breeding. There were no significant differences between the mean testicular biometry, scrotal circumference and the percentage of spermatozoa reactive to the hypoosmotic test (43.9 ± 21.1% vs. 43.6 ± 19.3%) in bulls classified as sound and unsound for breeding (P > 0.05), although there were significant differences between the averages for all physical and morphological aspects of the sperm between the two groups (P < 0.05). The hypoosmotic test did not correlate with the main characteristics of semen quality (P > 0.05). In this study, the hypoosmotic test was not an efficient predictor of the reproductive potential of young Nelore bulls.(AU)

Relação entre perímetro escrotal e características produtivas e reprodutivas em bovinos de corte: uma revisão / Relationship between scrotal circumference and productive and reproductive traits in beef cattle: a review

Os programas de melhoramento genético visam mudar a herança nas populações pelo aumento dos genes desejáveis ou aumento da frequência de genótipos desejáveis com o objetivo de aumentar a produtividade dos rebanhos. Para tanto, faz-se necessário o conhecimento de parâmetros genéticos (herdabilidades e correlações genéticas) que orientem a escolha dos métodos de seleção. Apesar de a seleção para aumento do perímetro escrotal (PE) não trazer benefício econômico direto, o PE é uma característica que possui herdabilidade de moderada a alta e que é correlacionada com o ganho de peso e com características reprodutivas de fêmeas e machos. O PE se torna, assim, um dos critérios de seleção mais utilizado para eficiência reprodutiva do gado de corte. Esta revisão discute estimativas de herdabilidade e correlações genéticas para PE em bovinos de corte, visando à precocidade reprodutiva e ponderal, além de maior ganho econômico com o rebanho. (AU)

The breeding programs aim changing the genetic heritage of animals by the incorporation of new genes that increase the productivity of herd. Therefore, it is necessary the knowledge of genetic parameters (heritability and genetic correlations) to guide the choice of selection methods. Despite selection for increased scrotal circumference (SC) does not bring direct economic benefits, the SC is a characteristic that has moderate to high heritability, correlated with weight gain and reproductive traits of females and males. The SC thus becomes one of the selections criteria most commonly used for reproductive efficiency of beef cattle. Thus, the objective of this review is to discuss estimates of heritability and genetic correlations for SC in beef cattle, aiming at early reproductive and weight as well as greater economic gain of the herd. (AU)

Relação entre perímetro escrotal e características produtivas e reprodutivas em bovinos de corte: uma revisão / Relationship between scrotal circumference and productive and reproductive traits in beef cattle: a review

Os programas de melhoramento genético visam mudar a herança nas populações pelo aumento dos genes desejáveis ou aumento da frequência de genótipos desejáveis com o objetivo de aumentar a produtividade dos rebanhos. Para tanto, faz-se necessário o conhecimento de parâmetros genéticos (herdabilidades e correlações genéticas) que orientem a escolha dos métodos de seleção. Apesar de a seleção para aumento do perímetro escrotal (PE) não trazer benefício econômico direto, o PE é uma característica que possui herdabilidade de moderada a alta e que é correlacionada com o ganho de peso e com características reprodutivas de fêmeas e machos. O PE se torna, assim, um dos critérios de seleção mais utilizado para eficiência reprodutiva do gado de corte. Esta revisão discute estimativas de herdabilidade e correlações genéticas para PE em bovinos de corte, visando à precocidade reprodutiva e ponderal, além de maior ganho econômico com o rebanho.

The breeding programs aim changing the genetic heritage of animals by the incorporation of new genes that increase the productivity of herd. Therefore, it is necessary the knowledge of genetic parameters (heritability and genetic correlations) to guide the choice of selection methods. Despite selection for increased scrotal circumference (SC) does not bring direct economic benefits, the SC is a characteristic that has moderate to high heritability, correlated with weight gain and reproductive traits of females and males. The SC thus becomes one of the selections criteria most commonly used for reproductive efficiency of beef cattle. Thus, the objective of this review is to discuss estimates of heritability and genetic correlations for SC in beef cattle, aiming at early reproductive and weight as well as greater economic gain of the herd.

Estimativas de herdabilidades e correlações genéticas entre características reprodutivas em touros da raça Nelore / Genetic correlations and heritability estimates of reproductive traits of Nellore bulls

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.

Heritability estimate and genetic correlations of reproductive features in Nellore bulls, offspring of super precocious, precocious and normal cows under extensive farming conditions.

The present work aimed to estimate heritability and genetic correlations of reproductive features of Nellore bulls, offspring of mothers classified as superprecocious (M1), precocious (M2) and normal (M3). Twenty one thousand hundred and eighty-six animals with average age of 21.29 months were used, evaluated through the breeding soundness evaluation from 1999 to 2008. The breeding soundness features included physical semen evaluation (progressive sperm motility and sperm vigour), semen morphology (major, minor and total sperm defects), scrotal circumference (SC), testicular volume (TV) and SC at 18 months of age (SC18). The components of variance, heritability and genetic correlations for and between the features were estimated simultaneously by restricted maximum likelihood, with the use of the vce software system vs 6. The heritability estimates were high for SC18, SC and TV (0.43, 0.63 and 0.54; 0.45, 0.45 and 0.44; 0.42, 0.45 and 0.41, respectively for the categories of mothers M1, M2 and M3) and low for physical and morphological semen aspects. The genetic correlations between SC18 and SC were high, as well as between these variables with TV. High and positive genetic correlations were recorded among SC18, SC and TV with the physical aspects of the semen, although no favourable association was verified with the morphological aspects, for the three categories of mothers. It can be concluded that the mother's sexual precocity did not affect the heritability of their offspring reproduction features.

Estimativas de herdabilidades e correlações genéticas entre características reprodutivas em touros da raça Nelore / Genetic correlations and heritability estimates of reproductive traits of Nellore bulls

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)

Aplasia segmentar bilateral do epidídimo na espécie bubalina: relato de caso / A case of bilateral segmental aplasia of the epididymis in a buffalo

Este estudo reporta um bubalino mestiço, com 27 meses de idade, 188 kg de peso de carcaça, sem histórico reprodutivo. Sangue foi coletado para posterior determinação hormonal. Testículos e epidídimos foram avaliados macroscopicamente e microscopicamente. Os testículos apresentaram-se simétricos, caudas dos epidídimos ausentes e cabeças com presença de cistos. Parênquima testicular e mediastino demonstraram edema. Concentrações de testosterona e androstenediona foram de, respectivamente, 9,88 pg/mL e 3,00 ng/mL. Observou-se alto grau de degeneração testicular. Considerando-se a esterilidade do animal, associada à origem genética da patologia, sugere-se que machos acometidos sejam descartados da reprodução.(AU)

This case report involves a slaughtered cross-breed buffalo, age 27 months, carcass weight, 188 kg, without reproductive history. Blood was collected for later hormone determination. Testes and epididymes were evaluated macroscopically and microscopically. The testes were symmetrical. However, the epididymal tails were absent and the epididymal heads had cysts. Testicular parenchyma and mediastinum were swollen. Testosterone and androstenedione concentrations were 9.88 pg/mL and 3.00 ng/mL, respectively. A high degree of testicular degeneration was observed. That this condition causes esterility, coupled with the genetic origin of the disease, it is suggested that affected animals are culled.(AU)

Aplasia segmentar bilateral do epidídimo na espécie bubalina: relato de caso / A case of bilateral segmental aplasia of the epididymis in a buffalo

Este estudo reporta um bubalino mestiço, com 27 meses de idade, 188 kg de peso de carcaça, sem histórico reprodutivo. Sangue foi coletado para posterior determinação hormonal. Testículos e epidídimos foram avaliados macroscopicamente e microscopicamente. Os testículos apresentaram-se simétricos, caudas dos epidídimos ausentes e cabeças com presença de cistos. Parênquima testicular e mediastino demonstraram edema. Concentrações de testosterona e androstenediona foram de, respectivamente, 9,88 pg/mL e 3,00 ng/mL. Observou-se alto grau de degeneração testicular. Considerando-se a esterilidade do animal, associada à origem genética da patologia, sugere-se que machos acometidos sejam descartados da reprodução.

This case report involves a slaughtered cross-breed buffalo, age 27 months, carcass weight, 188 kg, without reproductive history. Blood was collected for later hormone determination. Testes and epididymes were evaluated macroscopically and microscopically. The testes were symmetrical. However, the epididymal tails were absent and the epididymal heads had cysts. Testicular parenchyma and mediastinum were swollen. Testosterone and androstenedione concentrations were 9.88 pg/mL and 3.00 ng/mL, respectively. A high degree of testicular degeneration was observed. That this condition causes esterility, coupled with the genetic origin of the disease, it is suggested that affected animals are culled.

Reproductive parameters of Mangalarga Marchador mares in a commercial embryo transfer programme.

The objective of this study is to evaluate the reproductive efficiency in donors and recipient Mangalarga Marchador mares in commercial programmes of embryo transfer (ET) and the effects of some reproductive characteristics and ET methodology on conception rates in the recipient mares. A total of 1140 flushing procedures were performed and 830 embryos (72.8%) were recovered. There were no differences between the rates of embryonic recovery in the different breeding seasons (p > 0.05) and 92.8% of the recovered embryos were 8-9 days old. There was no difference in the embryonic recovery regarding the collection order from the first to the ninth embryo collection along the breeding season, as well as among mares inseminated during the foal heat or subsequent cycles (p > 0.05). Pregnancy rates observed in the total period of all reproductive seasons at 15, 30, 45 and 60 days of pregnancy were 73.4, 69.9, 66.7 and 64.5%, respectively. Differences in pregnancy rate and early embryonic loss rates were not observed between embryos transferred immediately after collection (66.8% and 13.5%) and embryos transported at room temperature for periods of < 1 h (62.9% and 14.4%; p > 0.05). Pregnancy rates were higher when the interval between ovulations of donor and recipient mares remained between -3 and -2 days (p < 0.05), and the lowest rates were observed for intervals of -6 days (p < 0.05) with intermediary values for intervals of -1, 0 and +1 (p > 0.05). Embryonic loss rates, however, did not differ between intervals of ovulation's synchronism between donor and recipient mares (p > 0.05). This flexibilization in the ovulatory synchronism between donor and recipient mares optimizes the use of recipient mares, thus reducing costs and facilitating management of horse breeding farms.

Immotile short-tail sperm defect in Nelore (Bos taurus indicus) breed bulls.

This case study reported the presence of short tail sperm defect in the semen of three Nelore breed bulls. The sperm presented 0% of motility in the three animals evaluated and a total of 70%, 61% and 34% of pathologies of the intermediate piece of the tail respectively for animals 1, 2 and 3. It was identified that animals 2 and 3 had high degree of inbreeding, although no relationship was found with animal 1. Animal 2 was the only one that presented inbreeding coefficient (6.25%). His half-sib (animal 3) and animal 1, from the same herd, had shown no inbreeding, showing that inheritance is not the only determinant factor for its incidence on Nelore males.

Dinâmica folicular ovariana na espécie bubalina / Ovarian follicular dynamics in buffaloes

Considerando o aumento da população mundial de búfalos, pesquisadores do mundo inteiro têm investigado os eventos biológicos envolvidos na foliculogênese dessa espécie, com o intuito de solucionar as dificuldades para a detecção de estro, diminuir o impacto da estacionalidade reprodutiva e aprimorar biotecnologias reprodutivas, como a produção e a manipulação de embriões. Os búfalos são considerados animais sazonais (dias curtos), com duração do ciclo estral variando entre 16 a 33 dias, estro com cerca de cinco a 27 horas e ovulação ocorrendo entre 24 a 48 horas após o início do estro ou seis a 21 horas após o final do estro. O ovário da búfala é ovoide e consideravelmente menor do que o da vaca, apresentando menor número de folículos primordiais e maior taxa de atresia folicular. Os folículos primordiais, primários, secundários e terciários formados no ovário têm em média: 35; 25 a 80; 50 a 100 e 100 a 300 μm de diâmetro, respectivamente. O corpo lúteo, geralmente menor do que o da vaca, pode atingir peso e diâmetro máximo de 2,3 g e de 15 mm, respectivamente, e tem influência negativa no número de folículos superficiais. Os primeiros estudos relacionados ao crescimento folicular em bubalinos registraram a presença de padrões de uma, duas ou três ondas foliculares, propondo, desta forma, que as búfalas apresentam comportamento folicular semelhante ao de vacas, mas com suas peculiaridades. O objetivo desta revisão foi descrever as principais estruturas e os eventos envolvidos na dinâmica folicular ovariana em bubalinos.(AU)

Considering the increasing world population of buffaloes, researchers have been investigating biological events involved in the folliculogenesis of this specie. The main aims are to understand why r the detection of oestrus is difficult in this specie, to reduce the impact of reproductive seasonality in breeding efficiency and to improve the results obtained with the use of reproductive biotechnology, such as production and manipulation of embryos. The buffaloes are considered seasonal animals (short days) with oestrous cycle length ranging from 16 to 33 days, being the oestrous length approximately 5 to 27 hours and the ovulation occurring between 24 to 48 hours after the onset of oestrus or 6 to 21 hours after the end of oestrus. The buffalo ovary is ovoid and considerably smaller than bovine ovaries, showing fewer primordial follicles and higher rate of follicular atresia. The primordial, primary, secondary and tertiary follicles produced in the ovary are on average: 35, 25 to 80, 50 to 100, and 100 to 300 μm in diameter, respectively. The corpus luteum is usually smaller than that of bovine and its maximum weight and diameter are 2.3 g and 15mm, respectively, and has negative influence on the number of superficial follicles. Initial studies focusing follicular growth in buffaloes reported one, two or three follicular waves patterns, suggesting that buffaloes have follicular growth behavior similar to that found in cows, with some specific differences. The purpose of this review is to describe the main structures and events involved in ovarian follicular dynamics in buffaloes.(AU)

Dinâmica folicular ovariana na espécie bubalina / Ovarian follicular dynamics in buffaloes

Considerando o aumento da população mundial de búfalos, pesquisadores do mundo inteiro têm investigado os eventos biológicos envolvidos na foliculogênese dessa espécie, com o intuito de solucionar as dificuldades para a detecção de estro, diminuir o impacto da estacionalidade reprodutiva e aprimorar biotecnologias reprodutivas, como a produção e a manipulação de embriões. Os búfalos são considerados animais sazonais (dias curtos), com duração do ciclo estral variando entre 16 a 33 dias, estro com cerca de cinco a 27 horas e ovulação ocorrendo entre 24 a 48 horas após o início do estro ou seis a 21 horas após o final do estro. O ovário da búfala é ovoide e consideravelmente menor do que o da vaca, apresentando menor número de folículos primordiais e maior taxa de atresia folicular. Os folículos primordiais, primários, secundários e terciários formados no ovário têm em média: 35; 25 a 80; 50 a 100 e 100 a 300 μm de diâmetro, respectivamente. O corpo lúteo, geralmente menor do que o da vaca, pode atingir peso e diâmetro máximo de 2,3 g e de 15 mm, respectivamente, e tem influência negativa no número de folículos superficiais. Os primeiros estudos relacionados ao crescimento folicular em bubalinos registraram a presença de padrões de uma, duas ou três ondas foliculares, propondo, desta forma, que as búfalas apresentam comportamento folicular semelhante ao de vacas, mas com suas peculiaridades. O objetivo desta revisão foi descrever as principais estruturas e os eventos envolvidos na dinâmica folicular ovariana em bubalinos.

Considering the increasing world population of buffaloes, researchers have been investigating biological events involved in the folliculogenesis of this specie. The main aims are to understand why r the detection of oestrus is difficult in this specie, to reduce the impact of reproductive seasonality in breeding efficiency and to improve the results obtained with the use of reproductive biotechnology, such as production and manipulation of embryos. The buffaloes are considered seasonal animals (short days) with oestrous cycle length ranging from 16 to 33 days, being the oestrous length approximately 5 to 27 hours and the ovulation occurring between 24 to 48 hours after the onset of oestrus or 6 to 21 hours after the end of oestrus. The buffalo ovary is ovoid and considerably smaller than bovine ovaries, showing fewer primordial follicles and higher rate of follicular atresia. The primordial, primary, secondary and tertiary follicles produced in the ovary are on average: 35, 25 to 80, 50 to 100, and 100 to 300 μm in diameter, respectively. The corpus luteum is usually smaller than that of bovine and it’s maximum weight and diameter are 2.3 g and 15mm, respectively, and has negative influence on the number of superficial follicles. Initial studies focusing follicular growth in buffaloes reported one, two or three follicular waves patterns, suggesting that buffaloes have follicular growth behavior similar to that found in cows, with some specific differences. The purpose of this review is to describe the main structures and events involved in ovarian follicular dynamics in buffaloes.