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1.
J Vet Med Sci ; 85(1): 111-116, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36450501

RESUMO

Bovine leukemia virus (BLV) is the etiologic agent of enzootic bovine leucosis. Our previous study showed the BLV existence in cattle kept in the Red River Delta Region of Vietnam. However, no positive samples were identified in beef cattle. Besides, information related to the BLV circulation in the remained parts of Vietnam is limited. Therefore, we tested the existence of BLV in 48 beef cattle kept in the Central Coast Regions. Nested PCR targeting the BLV-env-gp51 confirmed the prevalence of 14.6% in investigated regions. Phylogenetic analysis suggested the co-existence of genotypes 1 and 10. The close relationship between strains found in Vietnam, Thailand, Myanmar, and China was revealed suggesting the possibility of BLV transmission through the movement of live cattle.


Assuntos
Doenças dos Bovinos , Leucose Enzoótica Bovina , Vírus da Leucemia Bovina , Bovinos , Animais , Filogenia , Vírus da Leucemia Bovina/genética , Genótipo , Vietnã/epidemiologia , Leucose Enzoótica Bovina/epidemiologia , Doenças dos Bovinos/epidemiologia
2.
J Reprod Dev ; 58(2): 223-30, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22156379

RESUMO

To determine whether glucocorticoids affect the function of the bovine corpus luteum (CL) during the estrous cycle and early pregnancy, we examined the effects of exogenous cortisol or reduced endogenous cortisol on the secretion of progesterone (P4) and on pregnancy rate. In preliminary experiments, doses of cortisol and metyrapone (an inhibitor of cortisol synthesis) were established (n=33). Cortisol in effective doses of 10 mg blocked tumor necrosis factor-induced prostaglandin F(2α) secretion as measured by its metabolite (PGFM) concentrations in the blood. Metyrapone in effective doses of 500 mg increased the P4 concentration. Thus, both reagents were then intravaginally applied in the chosen doses daily from Day 15 to 18 after estrus (Day 0) in noninseminated heifers (n=18) or after artificial insemination (n=36). Pregnancy was confirmed by transrectal ultrasonography between Days 28-30 after insemination. Plasma concentrations of P4 were lower in cortisol-treated heifers than in control heifers on Days 17 and 18 of the estrous cycle (P<0.05). However, the interestrus intervals were not different between control and cortisol-treated animals (P>0.05). Moreover, metyrapone increased P4 and prolonged the CL lifespan in comparison to control animals (P<0.05). Interestingly, in inseminated heifers, cortisol increased the pregnancy rate (75%) compared with control animals (58%), whereas metyrapone reduced the pregnancy rate to 16.7% (P<0.05). The overall results suggest that cortisol, depending on the physiological status of heifers (pregnant vs. nonpregnant), modulates CL function by influencing P4 secretion. Cortisol may have a positive influence on CL function during early pregnancy, leading to support of embryo implantation and resulting in higher rates of pregnancy in heifers.


Assuntos
Bovinos/fisiologia , Corpo Lúteo/efeitos dos fármacos , Implantação do Embrião/efeitos dos fármacos , Fármacos para a Fertilidade Feminina/farmacologia , Glucocorticoides/farmacologia , Hidrocortisona/farmacologia , Técnicas Reprodutivas , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , Administração Intravaginal , Animais , Animais Endogâmicos , Antimetabólitos/administração & dosagem , Antimetabólitos/farmacologia , Corpo Lúteo/metabolismo , Corpo Lúteo/fisiopatologia , Indústria de Laticínios/métodos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacologia , Feminino , Fármacos para a Fertilidade Feminina/administração & dosagem , Fármacos para a Fertilidade Feminina/antagonistas & inibidores , Glucocorticoides/administração & dosagem , Glucocorticoides/antagonistas & inibidores , Hidrocortisona/administração & dosagem , Hidrocortisona/antagonistas & inibidores , Inseminação Artificial/veterinária , Metirapona/administração & dosagem , Metirapona/farmacologia , Polônia , Gravidez , Taxa de Gravidez , Progesterona/sangue , Progesterona/metabolismo
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