Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 470
Filtrar
1.
Anim. Reprod. (Online) ; 20(1): e20220051, 2023. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1427281

Resumo

There is a paucity of information with respect to group-training for artificial vagina and its influence on semen characteristics and sexual behavior of young untrained rams. A total of 18 healthy Najdi rams (with an initial body weight of 40-45 Kg and 7-8 month-old) were consequently used herein to test the usefulness of group-training for artificial vagina-mediated semen collection during the breeding season. Rams were randomly segregated into three groups (n = 6 rams per protocol), and the whole experiment was lasted for 10 weeks. The 1st group was subjected to a training protocol where one untrained ram was placed for 20 min with a teaser ewe, while the 2nd group were subjected to a protocol where one untrained ram was placed for 20 min with one trained ram and a teaser ewe, whereas the 3rd group were subjected to a protocol where three untrained rams were placed for 20 min with one trained ram and a teaser ewe. The obtained results clearly (P < 0.05) showed that training young rams in group has increased their sperm concentration and sexual stimulation, shortened the period of their training time, and descriptively had a complete training efficiency. The sexual stimulation of young untrained rams was intensified by the competition between rams in the co-presence of a trained ram. Collectively, these data may suggest that group-training of rams at puberty is a better protocol for AV-mediated semen collection compared to individual training. Some shortcomings were noted herein, but research dealing with this subject may very well improve the reproductive performance of young untrained rams.(AU)


Assuntos
Animais , Ovinos/fisiologia , Inseminação Artificial/veterinária , Análise do Sêmen , Comportamento Sexual Animal , Puberdade
2.
Ciênc. rural (Online) ; 53(2): e20210685, 2023. tab, graf
Artigo em Inglês | LILACS-Express | VETINDEX | ID: biblio-1384555

Resumo

ABSTRACT: This study developed a multiple linear regression model to estimate the Average rural prices (ARP) in Mexico with information taken from the period 1999-2018. The variables used to generate this model were the supply and demand as represented by planted area, yield, exports and the ARP of Agave Tequilero and Mezcalero. The analysis was carried out through the multiple linear regression model (MLRM) with the least squares method and using the statistical package R. The following variables were identified as having a significant influence on the determination of the ARP: the yield of Agave Mezcalero (YAM), the ARP of Agave Tequilero and the new planted area of Agave Tequilero (NPAATt-6) with an adjustment of 6 periods. Overall, three models were generated: model 2 was considered the most appropriate because it allows carrying out future forecasts with the new planted area with Agave Tequilero with 2 independent variables. YAM and NPAATt-6 were useful in predicting 65.5% of the annual variations in the ARP and helped recognize the negative trend of the Agave price from 2020 to 2024. Therefore, the use of the MLRM to estimate the Agave ARP can be a useful tool in predicting the performance of this crop.


RESUMO: O objetivo deste estudo é desenvolver um modelo de regressão linear múltipla para estimar o Preços médios rurais (PRM) no México com informações retiradas do período 1999-2018. As variáveis ​​utilizadas para gerar este modelo foram a oferta e a demanda representadas pela área plantada, produtividade, exportações e o PRM da Agave Tequilero e Mezcalero. A análise foi realizada através do modelo de regressão linear múltipla (MRLM) com o método dos mínimos quadrados e utilizando o pacote estatístico R. As seguintes variáveis ​​foram identificadas como tendo influência significativa na determinação do PRM: o rendimento da Agave Mezcalero (RAM), o PMR da Agave Tequilero e a nova área plantada da Agave Tequilero (NPAATt-6) com um ajuste de 6 períodos. Ao todo, foram gerados três modelos: o modelo 2 foi considerado o mais adequado porque permite fazer previsões futuras com a nova área plantada com Agave Tequilero com dois variáveis ​​independentes. RAM e NPAATt-6 foram úteis na previsão de 65,5% das variações anuais no ARP e ajudaram a reconhecer a tendência negativa do preço da Agave de 2020 a 2024. Portanto, o uso do MRLM para estimar o PMR da Agave pode ser uma ferramenta útil na previsão do desempenho desta cultura.

3.
Anim. Reprod. (Online) ; 20(1): e20220068, 2023. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1427298

Resumo

The cryopreservation reduces ram sperm quality, decreasing the pregnancy rate of ewes inseminated with thawed sperm. Hence, we aimed to improve the post-thaw quality of ram sperm replacing egg yolk on Tris-Glucose extender with different concentrations of LDL (2 or 8%), associated with the addition of 10 mM non-enzymatic antioxidants (ascorbic acid, hydroxytoluene butylate, ascorbyl palmitate, and trehalose). Semen samples were collected from six rams, split into different treatments, and frozen. After thawing, kinematic (CASA), structural (propidium iodide and carboxyfluorescein diacetate) and functional (hypoosmotic test) sperm membrane integrity was assessed. Total motility, VCL, and LIN were also assessed in thawed samples during 3 h of incubation (38 °C). The results showed that hydroxytoluene butylate at 10 mM in Tris-Glucose extender with 8% LDL improved velocity parameters immediately post-thaw compared with Tris-Glucose egg yolk extender, as well as prevented the reduction of total motility and VCL after incubation. There was no benefit of adding ascorbic acid and trehalose. Moreover, for the first time, it was shown the motility impairment promoted by ascorbyl palmitate to ram sperm.(AU)


Assuntos
Animais , Masculino , Preservação do Sêmen/veterinária , Ovinos/fisiologia , Análise do Sêmen/veterinária , Hidroxitolueno Butilado/administração & dosagem , Lipoproteínas/análise , Antioxidantes
4.
Arq. bras. med. vet. zootec. (Online) ; 75(4): 687-695, July-Aug. 2023. tab, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1447357

Resumo

This study was performed during the anestrous, involving 140 Akkaraman Kangal ewes whose lambs had died in the neonatal stage due to pneumonia and enteritis. Intravaginal sponge containing progesterone was placed to the animals (Group 1, n = 70) on day 0 and removed after 7 days, following which 263 µg PGF2α and 500 IU eCG were administered to the sheep. Ram introduction was performed for 7 days (days 8-14), starting from the day after the removal of the intravaginal sponge (day 8). The animals in Group 2 (n = 70) were not exposed to any treatment. Ram introduction was performed simultaneously in both the groups. To determine the reproductive response, reproductive parameters such as estrous, pregnancy, multiple pregnancy, and embryonic mortality rates, number of births, number of offspring, and fertility, as well as their economic implications, were compared between groups. Each reproductive parameter exhibited a statistical difference between groups. An economically positive trend was observed in the study group compared with the control group. It was concluded that in case of lamb losses in commercial farms that derive profit from lambing, pregnancy of ewes can be achieved via sexual stimulation without waiting for the next breeding season.


Este estudo foi realizado durante o anestrous, envolvendo 140 ovelhas Akkaraman Kangal cujos cordeiros haviam morrido no estágio neonatal devido a pneumonia e enterite. A esponja intragaginal contendo progesterona foi colocada aos animais (Grupo 1, n = 70) no dia 0 e removida após 7 dias, após os quais 263 µg PGF2α e 500 UI eCG foram administrados às ovelhas. A introdução do carneiro foi realizada por 7 dias (dias 8-14), a partir do dia seguinte à remoção da esponja intravaginal (dia 8). Os animais do Grupo 2 (n = 70) não foram expostos a nenhum tratamento. A introdução do carneiro foi realizada simultaneamente em ambos os grupos. Para determinar a resposta reprodutiva, foram comparados entre os grupos parâmetros reprodutivos, tais como estrogênio, gravidez, gravidez múltipla e taxas de mortalidade embrionária, número de nascimentos, número de descendentes e fertilidade, bem como suas implicações econômicas. Cada parâmetro reprodutivo exibia uma diferença estatística entre os grupos. Uma tendência economicamente positiva foi observada no grupo de estudo em comparação com o grupo de controle. Concluiu-se que no caso de perdas de cordeiros em fazendas comerciais que obtêm lucros com a parição, a gravidez de ovelhas pode ser obtida através de estimulação sexual sem esperar pela próxima estação de reprodução.


Assuntos
Animais , Reprodução , Gravidez , Ovinos , Morte Perinatal
5.
Ciênc. rural (Online) ; 53(2): e20210685, 2023. tab, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1412073

Resumo

This study developed a multiple linear regression model to estimate the Average rural prices (ARP) in Mexico with information taken from the period 1999-2018. The variables used to generate this model were the supply and demand as represented by planted area, yield, exports and the ARP of Agave Tequilero and Mezcalero. The analysis was carried out through the multiple linear regression model (MLRM) with the least squares method and using the statistical package R. The following variables were identified as having a significant influence on the determination of the ARP: the yield of Agave Mezcalero (YAM), the ARP of Agave Tequilero and the new planted area of Agave Tequilero (NPAATt-6) with an adjustment of 6 periods. Overall, three models were generated: model 2 was considered the most appropriate because it allows carrying out future forecasts with the new planted area with Agave Tequilero with 2 independent variables. YAM and NPAATt-6 were useful in predicting 65.5% of the annual variations in the ARP and helped recognize the negative trend of the Agave price from 2020 to 2024. Therefore, the use of the MLRM to estimate the Agave ARP can be a useful tool in predicting the performance of this crop.


O objetivo deste estudo é desenvolver um modelo de regressão linear múltipla para estimar o Preços médios rurais (PRM) no México com informações retiradas do período 1999-2018. As variáveis ​​utilizadas para gerar este modelo foram a oferta e a demanda representadas pela área plantada, produtividade, exportações e o PRM da Agave Tequilero e Mezcalero. A análise foi realizada através do modelo de regressão linear múltipla (MRLM) com o método dos mínimos quadrados e utilizando o pacote estatístico R. As seguintes variáveis ​​foram identificadas como tendo influência significativa na determinação do PRM: o rendimento da Agave Mezcalero (RAM), o PMR da Agave Tequilero e a nova área plantada da Agave Tequilero (NPAATt-6) com um ajuste de 6 períodos. Ao todo, foram gerados três modelos: o modelo 2 foi considerado o mais adequado porque permite fazer previsões futuras com a nova área plantada com Agave Tequilero com dois variáveis ​​independentes. RAM e NPAATt-6 foram úteis na previsão de 65,5% das variações anuais no ARP e ajudaram a reconhecer a tendência negativa do preço da Agave de 2020 a 2024. Portanto, o uso do MRLM para estimar o PMR da Agave pode ser uma ferramenta útil na previsão do desempenho desta cultura.


Assuntos
Modelos Lineares , Comércio , Produtos Agrícolas/economia , Agave , México
6.
Ciênc. anim. bras. (Impr.) ; 24: e-72745E, 2023. ilus, tab
Artigo em Inglês, Português | VETINDEX | ID: biblio-1417630

Resumo

Searching for improvements in semen cryopreservation, natural substances are commonly studied focusing to improve the sperm quality. The aim of this study were evaluated the effect of adding orange, pineapple, and beet juices in different concentrations and combinations to the ram semen cryopreservation extender. Five ejaculates from five adult rams were used. The semen pool was diluted in egg yolk-based extender and mixed with the following 15 treatments (at a final concentration of 400.106 sptz/mL): orange 10% (O10) and 15% (O15); pineapple 10% (P10) and 15% (P15); beet 10% (B10) and 15% (B15); pineapple + orange 10% (PO10) and 15% (PO15); pineapple + beet 10% (PB10) and 15% (PB15); beet + orange 10% (BO10) and 15% (BO15); pineapple + beet + orange 10% (PBO10) and 15% (PBO15); and the control group (CON). Post-thaw in 0.25 mL straws semen quality analysis of cryopreserved semen was performed by CASA and flow cytometry. Analysis of variance (PROC GLM) was carried out and the averages were compared using the SNK test. Pearson's correlation test was also performed. No effect was noted in the addition of juices to the semen extender prior to cryopreservation. Post-thawed, although, statistically similar to the control group, the total motility of the B10 group reached acceptable standards of total motility. In addition, B10 group showed the highest values (p< 0.05) of progressive motility than control group or other treatments. The addition of 10% beet juice to the ram semen extender can improve the cryopreservation of sperm motility.


Em busca de melhorias na criopreservação do sêmen, substâncias naturais são comumente estudadas com o objetivo de melhorar a qualidade do sêmen. O objetivo deste estudo foi avaliar o efeito da adição de sucos de laranja, abacaxi e beterraba em diferentes concentrações e combinações ao diluidor de criopreservação de sêmen ovino. Foram utilizados cinco ejaculados de cinco carneiros adultos. O pool de sêmen foi diluído em diluente à base de gema de ovo e misturado com os seguintes 15 tratamentos (na concentração final de 400x106 sptz/ml): laranja 10% (O10) e 15% (O15); abacaxi 10% (P10) e 15% (P15); beterraba 10% (B10) e 15% (B15); abacaxi + laranja 10% (PO10) e 15% (PO15); abacaxi + beterraba 10% (PB10) e 15% (PB15); beterraba + laranja 10% (BO10) e 15% (BO15); abacaxi + beterraba + laranja 10% (PBO10) e 15% (PBO15); e o grupo controle (CON). Pós-descongelação em palhetas de 0,25 ml a análise da qualidade do sêmen criopreservado foi realizada pelo CASA e citometria de fluxo. A análise de variância foi realizada e as médias comparadas pelo teste SNK. O teste de correlação de Pearson também foi realizado. Nenhum efeito foi observado na adição de sucos ao diluidor de sêmen antes da criopreservação. Após o descongelamento, embora estatisticamente semelhante ao grupo controle, a motilidade total do grupo B10 atingiu padrões aceitáveis de motilidade total. Além disso, o grupo B10 apresentou os maiores valores (p<0,05) de motilidade progressiva que o grupo controle ou os outros tratamentos. A adição de 10% de suco de beterraba ao diluente de sêmen ovino pode melhorar a criopreservação da motilidade espermática.


Assuntos
Animais , Masculino , Preservação do Sêmen/métodos , Diluição , Carneiro Doméstico , Sucos de Frutas e Vegetais/análise , Antioxidantes/administração & dosagem , Criopreservação , Beta vulgaris , Ananas , Citrus sinensis
7.
Ciênc. anim. bras. (Impr.) ; 24: e-75316E, 2023. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1447907

Resumo

The aim of this study was to determine the resistance of gastrointestinal nematodes in goats and sheep to the anthelmintic drugs levamisole, ivermectin, and albendazole in the metropolitan region of São Luís Island, Maranhão, Brazil. Fecal samples were collected from 150 animals across four different farms; two farms had goats, and the other two had sheep. The samples were then randomly divided into three to four groups of 10 animals: Group I: control, without treatment; Group II: ivermectin treatment; Group III: levamisole treatment; and Group IV: albendazole treatment. Stool samples were collected from the rectal ampulla one day before treatment and 10 days after anthelmintic treatment. Individual coproparasitological examinations were performed using the modified McMaster technique at the Animal Health Laboratory of the Federal Institute of Maranhão, Campus São Luís-Maracanã. The efficacies of the anthelmintic drugs against gastrointestinal nematodes in goats and sheep were: 14.28%, and 13.6% for ivermectin; 0% and 79.4% for levamisole; and 59.8% and 3.43% for albendazole, respectively Gastrointestinal nematodes demonstrated multiple anthelmintic resistance, as the percentage reduction in egg count was less than 95% and the lower limit of the confidence interval was less than 90%.


Objetivou-se determinar a resistência de nematoides gastrintestinais aos anti-helmínticos levamisol, ivermectina e albendazol em caprinos e ovinos da região metropolitana da Ilha de São Luís, Maranhão, Brasil. Foram coletadas amostras de fezes de 150 animais de quatro propriedades diferentes, sendo 2 com caprinos e 2 com ovinos, e aleatoriamente distribuídos de três a quatro grupos de 10 animais: Grupo I: grupo controle, sem tratamento. Grupo II: tratado com anti-helmíntico à base de ivermectina, administrado oralmente na dose de 200 mcg/kg; Grupo III: tratado com anti-helmíntico à base de levamisol, administrado oralmente na dose de 7,5mg/kg e Grupo IV: tratado com anti-helmíntico à base de albendazol administrado oralmente na dose de 3mg/kg. Amostras de fezes foram colhidas da ampola retal um dia antes do tratamento e 10 dias após o tratamento anti-helmíntico. Foram feitos exames coproparasitológicos individuais, pela técnica de McMaster modificada, no Laboratório de Sanidade Animal, do Instituto Federal do Maranhão (IFMA), Campus São Luís-Maracanã. A ivermectina, na espécie caprina, mostrou eficácia de 14,28%, enquanato para ovina, 13,6 e 52,2%. Considerando o levamisol na espécie caprina, não apresentou eficácia contra os nematoides gastrintestinais, enquanto para ovinos, apresentou eficácia de 79,4%. Já o albendazol, apresentou eficácia de 59,8% para caprinos, e 3,43% para ovinos. Os nematoides gastrintestinais demonstraram resistência múltipla (RAM), visto que a percentagem de redução da contagem de ovos foi inferior a 95% e o limite inferior do intervalo de confiança menor do que 90%.


Assuntos
Animais , Ivermectina , Ruminantes , Resistência a Medicamentos , Ovinos , Albendazol , Levamisol , Anti-Helmínticos , Nematoides
8.
Rev. bras. reprod. anim ; 47(3): 514-523, jul.-set. 2023.
Artigo em Português | VETINDEX | ID: biblio-1436646

Resumo

A criopreservação de sêmen é uma importante estratégia para o armazenamento de material genético de reprodutores ovinos e caprinos, considerados superiores do ponto de vista fenotípico, mas especialmente, pelos seus méritos genéticos. Hoje no Brasil apenas uma central regulamentada pelo MAPA está ema atividade, o que significa que existe pouca dose de sêmen comercial à disposição para programas de melhoramento genético. Programas de banco de sêmen podem ser realizado nas fazendas, entretanto, tem seu uso limitado a propriedade onde está o reprodutor. Neste caso, apesar de maiores limitações de estrutura e equipamentos para a execução do serviço, o domínio das variações da técnica de congelação de sêmen e o cuidado com as questões sanitárias dos reprodutores possibilitará ao Médico-Veterinário a execução do serviço com níveis adequados de segurança e qualidade das doses de sêmen produzidas. O objetivo deste estudo é apresentar e discutir critérios e metodologias para congelação de sêmen de pequenos ruminantes em diferentes condições, fruto de diversas experiências e trabalhos desenvolvidos por nosso grupo e outros, nos últimos vinte anos, e que tem possibilitado resultados satisfatórios.(AU


Sperm cryopreservation is an important strategy for the storage of genetic material from ovine and goat breeders, considered superior from the phenotypic point of view, but especially for their genetic merits. Today in Brazil only one center regulated by the Ministry of Agriculture, Livestock and Supply is in operation, which means that there is little dose of commercial semen available for genetic improvement programs. Semen bank programs can be carried out on farms; however, their use is limited to the property where the breeder is located. In this case, despite greater limitations of structure and equipment for the execution of the service, mastering variations in the semen freezing technique and taking care of the health issues of the breeders will enable the Veterinarian to perform the service with adequate levels of safety and quality of semen doses produced. This study aims to present and discuss criteria and methodologies for freezing semen from small ruminants under different conditions, the result of several experiences and works carried out by our group and others, in the last twenty years, which have enabled satisfactory results.(AU))


Assuntos
Animais , Masculino , Ruminantes/fisiologia , Criopreservação/veterinária , Análise do Sêmen , Melhoramento Genético
9.
Acta sci., Anim. sci ; 45: e57518, 2023. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1396821

Resumo

The objective was to evaluate fertility, cyclicality behavior, and sexual performance of Pantaneiro sheep throughout the year's photoperiods in Mato Grosso do Sul - Brazil. Two experiments were conducted. In experiment one, the ewes used aged between 2 and 4 years, distributed in three homogeneous groups of 54 animals and subjected to reproductive evaluation in three different predefined luminosity periods, consisting of autumn (11h 45 min.), spring (12h 30 min.), and summer (12h 55 min.). The characteristics studied were body weight (BW), body condition score (BCC), estrus distribution (EST), percentage of pregnant females per cycle (%P), plasma progesterone (PP), and fertility (F) in the three predefined seasons. The mating system used was controlled natural nocturnal and lasted for 45 days. Experiment two, evaluated the ram sexual activity. The males (10) were individually exposed to four ovariectomized ewes. The ewes cycled during evaluated seasons, and the highest fertility was observed in animals with BCC >2.75. The PP concentration differed among periods, and higher conception rates (F) were observed in autumn and spring. The rams (75%) had a medium of sexual performance when they performed more than two ejaculations in 20 min throughout the seasons. Pantaneiro sheep of both genders had a similar fertility index, with early and constant activity throughout the year, displaying no photoperiodism or seasonality.


Assuntos
Animais , Comportamento Sexual Animal/fisiologia , Ovinos/fisiologia , Fertilidade/fisiologia , Periodicidade , Brasil
10.
Acta sci. vet. (Impr.) ; 50: Pub. 1883, 2022. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1400871

Resumo

Background: Effect of the epigenetic factors on the male fertility is well proofed. Sperm acts as a carrier of genetic material, and its DNA methylome can affect maternal pregnancy rate and offspring phenotype. However, the research on the DNA methylation in the spermatozoids of livestock males, in particular rams, is still limited. To best of our knowledge the data about as a global as well as gene specific DNA methylation in ram spermatozoa from different breeds and ages are missed in the scientific literature. The present study was designed to analyze the relationship between methylation levels of the important for spermatogenesis gene SIRT1 in spermatozoa and fertilizing ability of sperm in rams from different breeds and ages. Materials, Methods & Results: The ejaculates of 16 rams from Lacaune, East Friesian and Assaf breeds at age between 18 to 96 months were evaluated. The kinematic parameters of 2 semen samples from each animal were estimated by CASA. The separated spermatozoa were used for DNA extraction followed by bisulfite conversion. The DNA methylation of SIRT1 was detected through quantitative methylation-specific PCR using 2 sets of primers designed specifically for bisulfite-converted DNA sequences to attach methylated and unmethylated sites. The breed and age effect on the gene SIRT1 methylation by ANOVA was estimated. Experimental females included 393 clinically healthy milk ewes (Lacaune, n = 131; East Friesian sheep, n = 100 and Assaf, n = 162) in breeding season. Reproductive performances (conception rate at lambing, lambing percentage and fecundity) of ewes, inseminated by sperm of the investigated rams, were statistically processed. ANOVA showed that the animal breed influences significantly on the level of DNA methylation of gene SIRT1 in ram spermatozoa (P = 0.002) An average value of DNA methylation of SIRT1 in ram sperm from Lacaune breed was significantly higher than in Assaf and East Friesian (81.21 ± 15.1% vs 36.7 ± 14.2% and 38.3 ± 18.6 respectively, P < 0.01). The highest percent of SIRT1 methylation was observed in old animals compared to the young and middle-age. Moderate and strong correlations (r from 0.44 to 0.71, P < 0.05) between the methylation level of the SIRT1 gene in rams' sperm and reproductive parameters of inseminated ewes in all breeds were established. Discussion: Our data are the first message about the effect of breed on the specificity of DNA methylation of gene SIRT1 in ram spermatozoa. These results demonstrated an existence of the sheep breeds with high and low level of DNA methylation of gene SIRT1 in ram sperm. Although the effect of age on the methylation level in sperm is still discussable, our results showed a moderate correlation between age and methylation level of SIRT1 in spermatozoa of rams. Taking into account that DNA methylation in sperm is stabilized with puberty onset and is a heritable epigenetic modification, it can be a promising marker of sperm quality in animal breeding. In all investigated breeds the rams with relatively high level of DNA methylation of gene SIRT1 in spermatozoa (50-68%) demonstrated a high conception rate at lambing (> 70%). In conclusion, the DNA methylation level of the SIRT1 gene in ram spermatozoa is determined by both the breed and the age of the animals and correlates with fertilizing ability of sperm.


Assuntos
Animais , Masculino , Espermatogênese , Ovinos/genética , Metilação de DNA/genética , Sirtuína 1/análise , Fatores Etários
11.
J. Anim. Behav. Biometeorol ; 10(4): e2240, Oct. 2022. graf, tab
Artigo em Inglês | VETINDEX | ID: biblio-1434695

Resumo

Thirty-nine autumn-born ram-lambs were used to study whether polymorphisms of the melatonin receptor 1A (MTNR1A) gene influence some reproductive parameters of Oct-born ram-lambs at 8 months of age. Animals were genotyped for their RsaI (CC, n=24; CT, n=6; TT, n=9) and Mn1I (GG, n=27; GA, n=6; AA, n=6) allelic variants of the MTNR1A gene. Liveweight (LW) was recorded bi-weekly until Jun, and scrotal perimeter (SP) was recorded once per month. From mid-Jan, blood samples were collected weekly to measure plasma testosterone concentrations. In mid-Jun, individual serving-capacity tests were performed. Testicular ultrasonography was performed at the end of the experiment. The effects of the week and gene polymorphism on LW, scrotal perimeter, and plasma testosterone concentrations were evaluated statistically by the GLM for repeated measures procedure. LW, SP, and plasma testosterone concentrations were significantly (P<0.001) affected by week, but neither of the polymorphisms of the melatonin receptor 1A (MTNR1A) gene affected these variables. In the serving tests, genotypes did not differ significantly in individual behaviors or the number of events (CC: 24.1±3.2, CT: 26.3±13.0, TT: 16.8±4.8, GG: 22.0±3.0, GA: 21.0±6.7, AA: 27.8±12.7). Testicular features assessed by ultrasonography did not differ significantly among genotypes. In conclusion, the polymorphisms of the melatonin receptor 1A (MTNR1A) gene did not have an effect on the reproductive characteristics of autumn-born ram lambs, based on serving capacity tests, testosterone secretion, and testicular measurements at 8 months of age.


Assuntos
Animais , Comportamento Sexual , Testículo , Testosterona , Ovinos , Receptor MT1 de Melatonina
12.
Bol. Inst. Pesca (Impr.) ; 48: e661, 2022. ilus, mapas, tab
Artigo em Inglês | VETINDEX | ID: biblio-1400912

Resumo

The aim of this study was to describe the traditional knowledge from artisanal fishermen related to marine artificial reef (MAR) ship Victory 8B and to identify possible changes in the fishery area after its installation. We performed single ethnographic interviews (n = 80) through a semistructured questionnaire, using participant observation, visual ethnography, and field diary recordings. All the interviewees were men from 27 to 77 years old, with low education levels and up to 60 years of experience in the fishery artisanal. Most of the interviewees (n = 71; 88.7%) recognize the presence of this MAR in the region and its role as a shelter for marine fauna and an attractor for species with commercial value. Even with fishery prohibition in the vicinity of MAR Victory 8B, most of the interviewees (n = 75; 93.7%) reported the practice in that area. According to the fishermen, the ship installation did not alter area the fishery, but the structure positively changed the activity by attracting more fish, increasing capture and profits. With that, from the perspective of the fishermen perception, MAR Vi-tory 8B fulfilled its role in the enrichment of the fish stock and the conservation of marine biodiversity in the region.


O objetivo deste estudo foi descrever os conhecimentos tradicionais dos pescadores artesanais relacionados ao recife artificial marinho (RAM) navio Victory 8B e identificar possíveis alterações na área de pesca após a sua instalação. Foram realizadas entrevistas etnográficas (n = 80) por meio de ques-tionário semi-estruturado, sendo aplicado o método de observação participante e uso do diário de campo. Todos os entrevistados eram homens com idades entre 27 e 77 anos, com baixa escolaridade e até 60 anos de experiência na pesca artesanal. A maioria dos entrevistados (n = 71; 88,7%) reconhece a presença deste RAM na região, seu papel como abrigo para a fauna marinha e como atrator de espécies com valor comercial. Mesmo com a proibição da pesca nas proximidades do RAM Victory 8B, a maioria dos entrevistados (n = 75; 93,7%) relatou a prática naquela área. Segundo os pescadores, a instalação do navio não alterou a área de pesca, mas a estrutura mudou positivamente a atividade, atraindo mais peixes, aumentando a captura e os lucros. Com isso, na percepção dos pescadores, o RAM Victory 8B cumpriu seu papel no enriquecimento do estoque pesqueiro e na conservação da biodiversidade marinha da região.


Assuntos
Animais , Fauna Marinha , Biodiversidade , Recifes de Corais , Caça , Navios , Brasil , Inquéritos e Questionários , Antropologia Cultural
13.
Acta amaz ; 52(3): 189-198, 2022. tab
Artigo em Inglês | VETINDEX | ID: biblio-1392765

Resumo

Cassava by-products are abundant and largely unused in familiy agro-industries in the Amazon region, where slow-growing broilers are commonly raised. Thus the incorporation of cassava by-products in broiler feed may provide starch enrichment for better zootechnical performance. We evaluated the use of cassava residues instead of corn in the diet of slow-growing broilers. We determined the chemical composition of cassava scrapings (CS) and cassava starch residue (CSR), and tested the digestibility of the residues in 192 broilers and three treatments: inclusion of 30 g kg-1 CS or CSR and a control without residue, with eight replicates of eight broilers each. Digestibility was assessed through collection of total excreta from 19 to 22 days of age. Apparent and corrected metabolizable energy, and apparent digestibility coefficients of dry matter, crude protein and crude energy were significantly higher for CSR than CS. Therefore, only CSR was used in a performance experiment using 324 broilers 30 to 90 days old, distributed in four treatments (0; 6.8; 13.4 and 20 g kg-1 CSR in feed) with nine replicates of nine broilers each. There was no significant difference among treatments in weight gain, feed intake, yield of carcass, breast and viscera, meat color, luminosity, pH, shear force, cooking-weight loss and drip loss. As there was a significant reduction in feed conversion and thigh and drumstick yield for 20 g kg-1, we suggest the incorporation of CSR up to 13.4 g kg-1.(AU)


Subprodutos da mandioca são abundantes e pouco utilizados nas agroindústrias familiares na Amazônia, onde é comum a criação de frangos de corte de crescimento lento. Portanto, a incorporação de subprodutos de mandioca na alimentação destes frangos pode proporcionar enriquecimento de amido para melhor desempenho zootécnico. Avaliamos a utilização de resíduos da mandioca na alimentação de frangos de crescimento lento em substituição ao milho. Determinamos a composição química da raspa de mandioca (RM) e do resíduo de amido de mandioca (RAM), e testamos a digestibilidade dos resíduos utilizando 192 frangos e três tratamentos: inclusão de 30 g kg-1 RM ou RAM e um controle sem mandioca, com oito repetições de oito frangos cada. Digestibilidade foi determinada por coleta de excretas totais dos 19 aos 22 dias de idade. Energia metabolizável aparente e corrigida e os coeficientes de digestibilidade aparente da matéria seca, proteína bruta e energia bruta foram significativamente maiores para RAM que RM. Assim, apenas RAM foi usado em um experimento de desempenho com 324 frangos de 30 a 90 dias de idade e quatro tratamentos (0; 6,8; 13,4 e 20 g kg-1 RAM na ração), com nove repetições de nove frangos cada. Os tratamentos não diferiram significativamente em ganho de peso, consumo de ração, rendimento de carcaça, peito e vísceras, cor da carne, luminosidade, pH, força de cisalhamento, e perda de peso por cozimento e gotejamento. Como houve redução significativa na conversão alimentar e no rendimento de coxa e sobrecoxa com 20 g kg-1, sugerimos o uso de RAM até 13,4 g kg -1.(AU)


Assuntos
Animais , Manihot/química , Ingestão de Alimentos/fisiologia , Carne/análise , Galinhas/crescimento & desenvolvimento , Digestão/fisiologia , Ração Animal/análise
14.
Semina ciênc. agrar ; 43(2): 841-854, mar.-abr. 2022. tab
Artigo em Inglês | VETINDEX | ID: biblio-1369179

Resumo

Cooling and freezing processes cause physical and chemical damage to sperm by cold shock and oxidative stress. This study aimed to evaluate the effect of two antioxidants on sperm parameters of cooled and frozen-thawed ram semen diluted in an egg yolk-based extender. Semen was collected from 30 rams and processed in two consecutive experiments to test the inclusion of different concentrations of quercetin and butylated hydroxytoluene (BHT) in an egg yolk-based semen extender. Dimethyl sulfoxide (DMSO) was added as a solvent to the semen extender in a ratio of 1 mL DMSO for 90 mg of quercetin and 1 mL DMSO for 880 mg of BHT. After collection, semen was diluted at 200 × 106 motile sperm/mL (control) and split into different groups in each experiment. In experiment 1, semen was diluted with the extender containing quercetin (Q5, 5 µg/mL; Q10, 10 µg/mL; Q15, 15 µg/mL) or DMSO alone (DMSO1, 0.055 µL DMSO per mL; DMSO2, 0.165 µL DMSO per mL). In experiment 2, semen was diluted with the extender with BHT (BHT1, 0.5 µg/mL; BHT2, 1 µg/mL; BHT3, 1.5 µg/mL) or DMSO alone (DMSO3, 0.375 µL DMSO per mL; DMSO4, 1.125 µL DMSO per mL). After dilution, the semen was divided into two aliquots. Treated ram sperm samples were also subjected to different storage methods. The first set of samples was cooled at 5 °C for 24 h, whereas the second set of samples was frozen-thawed. Sperm motility parameters and plasma membrane integrity (PMI) were evaluated immediately after dilution (0h) and 24 h after cooling and in the frozen-thawed samples via computer-assisted sperm analysis and epifluorescence microscopy, respectively. The inclusion of quercetin or BHT did not affect sperm motility parameters or PMI of fresh, cooled, or frozen-thawed sperm in this study (P < 0.05). However, further studies are needed to test the effects of these antioxidants on the fertility of cryopreserved ram semen.(AU)


O resfriamento e o congelamento causam danos físicos e químicos aos espermatozoides por choque térmico e estresse oxidativo. Portanto, este estudo teve como objetivo avaliar o efeito da inclusão de dois antioxidantes em um diluente à base de gema de ovo sobre os parâmetros espermáticos do sêmen ovino resfriado e congelado. Trinta carneiros tiveram o sêmen coletado e processado em dois experimentos consecutivos para testar a inclusão de diferentes concentrações de quercetina e hidroxitolueno butilado (BHT) em diluente de sêmen à base de gema de ovo. O DMSO foi adicionado como solvente ao diluente de sêmen em uma proporção de 1 mL de DMSO parra 90 mg de quercetina e 1 Ml de DMSO para 880 mg de BHT. Após a coleta, o sêmen foi diluído a 200 × 106 espermatozoides móveis/mL (Controle) e dividido em diferentes grupos em cada experimento. Experimento 1, Quercetina (Q5, 5 µg / mL; Q10, 10 µg / mL; Q15, 15 µg / mL) ou DMSO (DMSO1, 0,055 µL de DMSO por ml; DMSO2, 0,165 µL de DMSO / mL) foram adicionados ao extensor. Experimento 2, BHT (BHT1, 0,5 µg / mL; BHT2, 1 µg / mL; BHT3, 1,5 µg / mL) ou DMSO (DMSO3, 0,375 µL de DMSO por ml; DMSO4, 1,125 µL de DMSO / mL) foram adicionados à o extensor. Após a diluição, o sêmen foi dividido em duas alíquotas. O primeiro foi resfriado a 5 ° C por 24h, enquanto o segundo foi congelado. Os parâmetros de motilidade espermática e integridade da membrana plasmática (PMI) foram avaliados, imediatamente após a diluição (0h) e 24h após o resfriamento e nas amostras congeladas, pelo CASA e microscopia de epifluorescência, respectivamente. A inclusão de quercetina ou BHT não afetou os parâmetros de motilidade espermática e PMI de espermatozoides frescos, resfriados ou congelados (P < 0,05). Portanto, a inclusão de quercetina e BHT não beneficiou os parâmetros espermáticos do sêmen ovino submetido a armazenamento líquido a 5 ° C por 24h ou protocolo de congelamento no presente estudo. No entanto, mais estudos são necessários para testar o efeito desses antioxidantes na fertilidade do sêmen ovino criopreservado.(AU)


Assuntos
Animais , Masculino , Sêmen , Hidroxitolueno Butilado , Ovinos , Análise do Sêmen
15.
Acta sci. vet. (Impr.) ; 50: Pub. 1899, 2022. graf
Artigo em Inglês | VETINDEX | ID: biblio-1414963

Resumo

Background: The use of conventional artificial insemination (AI) in sheep production is usually associated with lower fertility rates when frozen semen is used. Cooled ram semen has been an alternative over frozen semen due to the higher viability, seminal quality and fertility rates following AI. The semen preservation process promotes sperm cell modifications similar to capacitation (capacitation-like) that causes cell damage affecting viability and seminal quality, but such effects are unclear for cooled semen. The aim of this study was to determine the status of sperm cell capacitation (CA) and acrosome reaction (AR) during ram semen processing and cooling under different extenders, dilution factors, and aerobiosis conditions as a function of storage time at 5o C. Materials, Methods & Results: Two consecutive ejaculates per day per male were collected from 2 adult rams by artificial vagina at 48-72 h intervals, in three replications. After macro- and microscopic evaluations, semen was segregated into groups under 3 extenders (Tris-egg yolk or TY, citrate-egg yolk or CY, skimmed milk or SM), 2 dilution factors (1 x 109 or Bi, 100 x 106 or Mi cells/mL), and 2 aerobiosis conditions (aerobic or A, semi-anaerobic or SA). Diluted semen was cooled to 5ºC and stored for up to 72 h, with evaluations every 24 h. Aliquots of fresh ejaculates and of each cooled diluted subgroup, according to extender, dilution, and aerobiosis, were collected at times T0 and T72 for determination of acrosome status and membrane integrity by the chlortetracycline (CTC) and trypan blue-Giemsa stainings, respectively. No differences were detected in sperm cell motility (M) and motility vigor (V) between fresh and diluted semen. After cooling, a significant decrease in M was observed after 48 h in CY and SM compared with fresh semen and 0 h of cooling, while V started to decrease after 24 h in CY compared with TY. Likewise, M/V from different dilutions and aerobic conditions decreased more significantly after 48 and 24 h of cooling, respectively. The sperm capacitation status did not show differences in the proportion of non-capacitated (NCA), CA and AR sperm cells between TY, CY, and SM extenders (NCA: 75.0%, 71.3%, 74.0%; CA: 15.7%, 17.2%, 15.9%; AR: 9.3%, 11.5%, 10.2%) or between Bi and Mi dilutions (NCA: 74.0%, 72.9%; CA: 15.9%, 16.6%; AR: 10.1%, 10.5%), respectively. However, differences (P < 0.05) were observed between A and SA aerobic conditions, with CA (17.0% vs. 15.5%) and AR (11.9% vs. 8.7%) rates being higher in A than SA, respectively, with no differences in NCA (71.1% vs. 75.8%), irrespective of the storage time. Sperm cell viability decreased after 48 h, especially in CY (P < 0.05). Discussion: Ram sperm cells can suffer irreversible damage due to thermal shock during cooling. Egg yolk-based extenders provide phospholipids and cholesterol to protect the sperm cell membrane during the thermal shock caused by the change in temperature. In this study, sperm cells had irreversible decreases in M/V, with increase in acrosome and plasma membrane damage after cooling to 5ºC. The largest and smallest decreases in M and V over time were observed in the CY and TY extenders, respectively. In addition to the extender type, the semen preservation method and storage time promoted changes in the capacitation status, AR and in sperm cell viability, which per se were associated with a decrease in semen fertility. In fact, the proportions of CA and/or AR sperm cells gradually increased over time after dilution and storage at 5ºC, with a negative correlation between sperm cell viability and M/V over time. In summary, extender and cooling time affected mostly M/V, while aerobiosis condition and dilution factor were more associated with acrosome status and sperm survival, with the extender having less impact on the acrosome status as a function of time.


Assuntos
Animais , Masculino , Preservação do Sêmen/métodos , Preservação do Sêmen/veterinária , Preservação de Tecido/métodos , Ovinos , Análise do Sêmen/veterinária , Sobrevivência Celular , Técnicas de Diluição do Indicador , Aerobiose
16.
Anim. Reprod. (Online) ; 19(4): e20220088, 2022. ilus
Artigo em Inglês | VETINDEX | ID: biblio-1414556

Resumo

This review addresses advances, directions and opportunities for research on sheep reproduction in the context of the global challenges of food security and climate change, and demand for 'clean, green and ethical' (CGE) animal management. The foundation of CGE management is an understanding of the physiological processes through which the reproductive system responds to changes in the animal's environment. These days, to the main environmental factors (photoperiod, nutrition, pheromones), we need to add stress from extreme weather events. With respect to nutrition in rams, we now have a deeper understanding of the responses of the brain centres that control gonadotrophin secretion (the kisspeptin system). At testis level, we have found that nutrition affects non-coding RNAs in Sertoli cells and germ cells, thus affecting the balance between cell proliferation and apoptosis. This proliferation-apoptosis balance is also affected during prenatal development, when undernutrition or stress in pregnant ewes seems to elicit epigenetic changes in developing gonads that could affect offspring fertility in adult life. With respect to nutrition in ewes, metabolic signals act directly on ovarian follicles, and thus change ovulation rate, but the variety of signals now includes the adipokines. An early concern was that nutritional supplements that increase ovulation rate would also increase embryo mortality but we now know that embryo survival is improved under field conditions. Finally, we had always thought that the efficiency gains from early puberty in lambs could only be achieved by accelerating fat accumulation, but we now know that faster muscle growth will achieve the same goal, offering two advantages in meat production systems. With respect to pheromones ('ram effect'), we have a deeper understanding of the brain responses (kisspeptin system) but, most importantly, a realization that the response of ewes to the ram signal involves cell division in memory centres. Many opportunities remain.(AU)


Assuntos
Animais , Reprodução/fisiologia , Ovinos/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Atrativos Sexuais/análise , Comportamento Sexual Animal , Criação de Animais Domésticos/métodos
17.
Acta sci. vet. (Impr.) ; 50(supl.1): Pub. 801, 2022. ilus
Artigo em Inglês | VETINDEX | ID: biblio-1401304

Resumo

Background: A cataract is an opacity of the crystalline structure that results in impaired vision. The congenital form manifests itself at birth or shortly thereafter and might also be inherited and therefore capable of passing on to descendants. Cataracts can be caused by systemic diseases, medications, toxic substances, radiation, metabolic alterations, dietary deficiencies, inflammation, traumatic injuries, age, or genetic factors. The few Blackbelly sheep herds are located in the northeast and north regions of Brazil and are considered rare, which could result in high levels of consanguinity. In this context, we report a case of congenital cataract in a Blackbelly lamb and its possible etiology. Case: A 3-month-old lamb presented with ophthalmic alterations since birth, with white and cloudy spots in both eyes and impaired vision. In the same herd, 3 elderly sheep showed similar ophthalmic alterations. The lamb was able to follow its dam, but when walking, bumped into small objects or very close to his vision field. The lamb managed to follow the herd and dodge large objects, suggesting partial vision loss. During a physical examination, both lens showed opacity and reduced corneal reflex, pupillary reflex to direct light, pupillary reflex to consensual light, and threat reflex. Ultrasonographic examination revealed that both lens presented hyperechogenicity. Hematological values were within the reference limits. In the same herd, three elderly sheep presented bilateral cataracts (2 rams and 1 ewe) in previous years, which at that time was attributed to natural aging. One ram was the lamb's grandfather. The other ram was the father of the female, both with cataracts. Based on history, physical examination, and complementary examinations, the lamb was diagnosed with bilateral congenital cataracts with a probable hereditary condition. Discussion: Multiple factors can be related to the etiology of cataracts, and it can be difficult to establish the correct etiology. Regarding the age of onset, cataracts can be classified mainly as congenital and senile. Senile cataract is a bilateral opacification process that involves the entire lens, with slow progression and gradual loss of vision with increasing age. In adult sheep, the high proportion of eyes affected by spontaneously arising cataracts could be related to age, increased exposure to sunlight, increased genetic susceptibility, or a combination of these factors. In this case, the herd had three adult elderly sheep with cataracts previously characterized as senile. However, after reviewing the genealogy, it was found that all animals had some degree of parentage, suggesting a hereditary factor. Congenital cataracts are expressed soon after birth, resulting from the malformation of fibers in the lens, and are generally nonprogressive. The congenital form may or may not be associated with hereditary factors. Inheritance cataracts have been reported in several breeds of dogs and usually occur as an autosomal recessive trait. Blackbelly sheep are rare in Brazil, favoring consanguinity, so we believe that cataracts are inherited in this herd. To control this ophthalmic alteration, all animals with crystalline opacities were excluded from reproduction, and the herd should be monitored in future cases.


Assuntos
Animais , Catarata/congênito , Catarata/etiologia , Ovinos , Cristalino/anormalidades
18.
Ciênc. anim. bras. (Impr.) ; 23: e-73601E, 2022. ilus, mapas, graf
Artigo em Inglês, Português | VETINDEX | ID: biblio-1417614

Resumo

Antioxidants are natural or synthetic substances that delay oxidation through one or more mechanisms, such as scavenging free radicals, inhibiting lipid peroxidation, and complexing with metals, inhibiting tissue destruction via oxidation. Antioxidants are commonly used in animal feed and the food industry to prevent the oxidation of animal-origin products. Moreover, natural oxidants are used increasingly in animal reproduction, especially for semen preservation. In this context, this study aimed to review the applications of natural antioxidants in animal reproduction. We observed that the bulk of the natural antioxidants, approximately 80.4%, were commercially acquired and used mainly for semen cooling/freezing (72%) with promising results (90%) in Sus scrofa (boar), Capra aegagrus hircus (goat), Gallus gallus domesticus (rooster), and Ovis aries (ram). However, further studies are needed to help determine the appropriate dosage of natural antioxidants for applications.


Antioxidantes são substâncias naturais ou sintéticas que facilitam o retardo da oxidação por um ou mais mecanismos, como sequestrar radicais livres, inibir a peroxidação lipídica e complexar com metais, inibindo a destruição tecidual via oxidação. Antioxidantes são comumente usados na alimentação animal e na indústria alimentícia para prevenir a oxidação de produtos de origem animal. Além disso, os oxidantes naturais estão sendo cada vez mais aplicados na reprodução animal, principalmente na preservação do sêmen. Nesse contexto, este trabalho teve como objetivo revisar a aplicação de antioxidantes naturais na reprodução animal. Observamos que os antioxidantes naturais foram geralmente adquiridos comercialmente (80,4%) e utilizados principalmente no resfriamento/congelamento de sêmen (72%) com resultados promissores (90%) em Sus scrofa (javali), Capra aegagrus hircus (cabra), Gallus gallus domesticus (galo) e Ovis aries (carneiro). No entanto, mais estudos devem ser realizados para ajudar a regular a dosagem de antioxidantes naturais para sua aplicação.


Assuntos
Animais , Masculino , Preservação do Sêmen/métodos , Vitamina E/uso terapêutico , Criopreservação/veterinária , Sequestradores de Radicais Livres/análise , Estresse Oxidativo , Cabras , Peroxidação de Lipídeos , Galinhas , Carneiro Doméstico , Sus scrofa
19.
Anim. Reprod. (Online) ; 19(1): e20220009, 2022. ilus, tab
Artigo em Inglês | VETINDEX | ID: biblio-1367902

Resumo

The assessment of morphology and digital image opacity may provide valuable information on the present embryo quality. Time-lapse imaging has been employed in research to establish a means of monitoring the dynamic nature of preimplantation embryo development. The aim of present study was to use time-lapse imaging for assessing various prospective morphometric and phototextural markers of the developmental potential of in vitro-derived ovine embryos. Oocytes were obtained by scarification of ovaries from nine Polish Longwool ewes. After in vitro maturation (IVM) and fertilization (IVF) of oocytes with fresh ram semen, the development of embryos to the blastocyst stage was monitored and evaluated using Primo Vision time-lapse imaging technology. Commercially available Image-Pro® Plus software was used to measure zona pellucida thickness, embryo diameter, total area of the perivitelline space, cellular grey-scale pixel intensity and cellular pixel heterogeneity. Statistical assessment of all attributes was done at various time points during embryo development (i.e., presumptive zygote stage: t(0); first cleavage detected at t(2) or t(3); and second cleavage detected at t(4) or t(6)). Out of thirty-seven zygotes analyzed in this study, five did not divide, 26 arrested before and six developed to the blastocyst stage. Our present results indicate that most parameters analyzed did not differ among embryos varying in their developmental fate except for the perivitelline space area that was greater (P<0.05) for non-dividing zygotes than future blastocysts at the presumptive zygote stage (4040±1850 vs. 857±262 µm2, respectively; means±SEM). Consequently, the measurement of perivitelline space at t(0) can potentially be used to prognosticate developmental potential of in vitro-produced ovine embryos albeit further confirmational studies are needed.(AU)


Assuntos
Animais , Feminino , Oócitos , Técnicas In Vitro , Ovinos/embriologia , Desenvolvimento Embrionário , Fertilização , Imagem com Lapso de Tempo
20.
J. Anim. Behav. Biometeorol ; 10(1): 2205, jan. 2022. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1438121

Resumo

A well-established activity in Greece and other Mediterranean countries is sheep farming. Karagouniko and Chios sheep are promising breeds and targets for the reproductive physiologist's attention. Under this context, part of the reproductive physiology of Karagouniko and Chios was investigated, taking into account the environment. Specifically, four time periods were considered; April-June (Long days, increasing photoperiod length), July-September (Long days, decreasing photoperiod length), October-December (Short days, decreasing photoperiod length), and January-March (Short days, increasing photoperiod length). The effect of the period on the concentration of the testosterone (main male hormone) in rams of the breeds above was studied, by using repeated measures analysis of variance, also taking into account the environmental variables air temperature, relative humidity, sunshine, rainfall, and photoperiod, in the Artificial Insemination Center of Karditsa (39°21'18''N, 21°54'19''E), Greece. The lowering of photoperiod from April-June to July-September (long days) and afterward, even more to October-December (short days) coincided with a progressive increase of testosterone in both breeds. Photoperiod seems to have a major role in the concentration of Karagouniko and Chios breeds' testosterone compared to the other environmental variables. When considering the whole experimental period, Chios sheep had significantly higher (P < 0.05) testosterone (1.95 ng/ml) than the Karagouniko one (1.55 ng/ml). Our findings could contribute towards the more rational exploitation of the examined sheep breeds.(AU)


Assuntos
Animais , Testosterona/análise , Ovinos/fisiologia , Fenômenos Reprodutivos Fisiológicos , Estações do Ano , Fotoperíodo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA