991 resultados para cattle, follicle aspiration, FSH.


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Since their domestication in the Neolithic, cattle have belonged to our cultural heritage. The reconstruction of their history is an active field of research 1 that contributes to our understanding of human history. Archeological data are now supplemented by analyses of modern and ancient samples of cattle with DNA markers of maternal, paternal, or autosomal inheritance. The most recent genetic data suggest that maternal lineages of taurine cattle originated in the Fertile Crescent with a possible contribution of South-European wild cattle populations, while zebu cattle originate from the Indus Valley. Subsequently, cattle accompanied human migrations, which led to the dispersal of domestic cattle of taurine, indicine, or mixed origin over Asia, Africa, Europe, and the New World. This has resulted in their adaptation to different environments and considerable variation in appearance and performance. More recently, rational management of breeding led to international movements of sires, which again changed the global patterns of genetic diversity.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The diagnosis of rabies in bats is usually performed using the brain of suspected animals. The main hypothesis tested by the present study was whether the aspiration method using a plastic pipette (Pasteur type) was effective in the collection of bat brain sample for rabies diagnosis when compared to the skull-opening method. A total of 200 bats of 4 species were studied: Molossus rufus E. Geoffroy, 1805, Molossus molossus (Pallas, 1766), Artibeus lituratus (Olfers, 1818) and Myotis nigricans (Schinz, 1821). The proportion of brain weight compared to body weight was statistically higher when using the traditional method, although the brain mass collected by the aspiration method was enough for rabies diagnosis and did not damage any skull biometric characteristics. The results demonstrate that both collection methods detected positive samples, while the aspiration method has the advantage of skull preservation, permitting the identification of the species.

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This study evaluated the effect of different concentrations of selenium (Se) supplementation on cattle anti-rabies humoral immune response, serum Se concentrations and cortisol levels. Sixty uncastrated male Nelore calves from 10 to 12 months grazing on Brachiaria decumbens forage were studied. The animals were assigned to one of four groups (n = 15 each), which received non-supplemented diets (Gc) or supplemented with daily and individual Selenium ( Se) concentrations of 3.6 mg (G(3.6)), 5.4 mg (G(5.4)) or 6.4 mg (G(6.4)). The calves were immunized on day 0 with one dose of commercial liquid inactivated rabies vaccination. on days 15, 30, 60, 90 and 120, the cattle underwent the same stressing procedures used for vaccination in the corral. Cattle blood samples were collected after vaccination and stressing procedures to determine serum Se levels, rabies antibody titers and serum cortisol. Se levels were also determined in forage samples collected from the paddocks in which the cattle were held. Se concentration in B. decumbens was 0.04 mg of Se/kg dry matter. Baseline Se levels obtained on day 0 were higher in Gc than in G(5.4) and G(6.4) (P = 0.005). Serum Se levels decreased in Gc throughout the experiment (P < 0.004), increased in G(3.6) (P < 0.000) and G(5.4) (P < 0.000) and were kept high from day 60 on in group G(6.4) (P < 0.002). Rabies antibody titers did not differ among control and supplemented groups. However, 120 days after vaccination rabies antibody titers were kept above protective levels (>= 0.5 UI/mL) only in group G(3.6) (P < 0.00002), whereas they dropped in the other groups (P < 0.05). Serum cortisol levels did not differ among the experimental groups (P = 0.79), reached peak levels on day 90 and returned close to baseline levels on day 120. Se and cortisol levels were not markedly correlated. Serum cortisol and rabies antibody titers were correlated only in group G(6.4), on day 60 (R = 0.513; P = 0.05) and 120 (R = 0.644; P = 0.009). Serum Se and rabies antibody titers were correlated only in group G(6.4), on day 60 (R = -0.580; P = 0.023). In conclusion: a) the profile of Se variation is different among groups receiving different concentrations of this element; b) the supplementation dosage of 3.6 mg Se/animal/day is efficient to treat/prevent marginal Se deficiency; c) individual supplementation with daily concentrations of 3.6 mg Se enhances the maintenance of rabies antibody titers in cattle; d) individual supplementation with daily concentrations of 3.6; 5.4 and 6.4 mg Se are ineffective in reducing serum cortisol; e) repeated cattle handling in corrals stress animals that adapt to these procedures, although serum cortisol does not return to baseline levels by 120 days; and f) the stress generated by repeated management in cattle in the corral does not diminish antibody titers after vaccination against rabies.

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P>In this study, Bayesian analysis under a threshold animal model was used to estimate genetic correlations between morphological traits (body structure, finishing precocity and muscling) in Nelore cattle evaluated at weaning and yearling. Visual scores obtained from 7651 Nelore cattle at weaning and from 4155 animals at yearling, belonging to the Brazilian Nelore Program, were used. Genetic parameters for the morphological traits were estimated by two-trait Bayesian analysis under a threshold animal model. The genetic correlations between the morphological traits evaluated at two ages of the animal (weaning and yearling) were positive and high for body structure (0.91), finishing precocity (0.96) and muscling (0.94). These results indicate that the traits are mainly determined by the same set of genes of additive action and that direct selection at weaning will also result in genetic progress for the same traits at yearling. Thus, selection of the best genotypes during only one phase of life of the animal is suggested. However, genetic differences between morphological traits were better detected during the growth phase to yearling. Direct selection for body structure, finishing precocity and muscling at only one age, preferentially at yearling, is recommended as genetic differences between traits can be detected at this age.

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A new outbreak of Vaccinia virus was observed in Southwest region of São Paulo State. Brazil. The disease was observed in four small dairy farms with manual milking. Lesions were detected in cattle and in humans previously vaccinated and not vaccinated against smallpox. Although several reports of Vaccinia virus outbreaks have been occuring in Brazil, it was not yet reported in this region. This Outbreak reinforces the Viral circulation in Our country. The disease in persons previously vaccinated and not vaccinated against smallpox reinforces the absence of immunity, the risk to the human health, and the need for more epidemiologic and immunologic studies.

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P>In developing countries such as Brazil, where canine rabies is still a considerable problem, samples from wildlife species are infrequently collected and submitted for screening for rabies. A collaborative study was established involving environmental biologists and veterinarians for rabies epidemiological research in a specific ecological area located at the São Paulo State, Brazil. The wild animals' brains are required to be collected without skull damage because the skull's measurements are important in the identification of the captured animal species. For this purpose, samples from bats and small mammals were collected using an aspiration method by inserting a plastic pipette into the brain through the magnum foramen. While there is a progressive increase in the use of the plastic pipette technique in various studies undertaken, it is also appreciated that this method could foster collaborative research between wildlife scientists and rabies epidemiologists thus improving rabies surveillance.