958 resultados para Nelore (Zebu) - Reprodução
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The objective of this study was evaluate the effects of immunocastration on body weight gain, carcass characteristics and meat quality of Nellore beef cattle. Eighty Nellore beef cattle, with initial body weight of 357 +/- 8.63 kg, were placed in feedlots and distributed in two treatments (40 animals per treatments) as follow: one - non-vaccinated bulls and two - immunocastrated bulls (Bopriva (R), Pfizer Animal Health). The animals placed on treatment two were vaccinated in two doses, first application 30 days before they arrive on the feedlots and second on the day they arrive on feedlots. After 67 days of experimental period, was calculated the daily gain of live weight in kg/day of the 80 animals and selected 20 animals from each treatment for the slaughter and carcass evaluations, and ten from each group for the meat analyzes. The data were submitted to analysis of variance. Immunocastrated animals showed lower daily weight gain, hot carcass weight, carcass yield, pH, leg thickness, muscle depth, loin muscle area, carcass muscle percentage, shear force and moisture. However, this animals had higher concentration of lactate and cortisol blood, chest depth, fat thickness, finishing degree, a *, b * and c*, liquid loss in thawing process, myofibrillar fragmentation index and ether extract of meat when compared to non-vaccinated bulss. The immunocastration (Bopriva (R)) is an alternative for improving the quality of meat by the higher fat deposition and by the reduction of the shear force of the meat when compared to non-vaccinated bulls.
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The objective was to evaluate fatty acids composition of the back fat in loin meat (Longissimus muscle) from Nellore and Canchim young bulls. The animals were finished at feedlot and received sugar cane diets with two concentrate levels (40 and 60% of dry matter). The concentrates were formulated with sunflower grains, corn, soybean meal, dry sugar cane yeast, urea and mineral mixture. The experimental design was a completely randomized design with a 2x2 factorial arrangement (genetic group x concentrate level), and the results were submitted to the variance analysis and means compared by Tukey test at 5% probability, when the interaction was significant. The loin backfat of Nellore bulls had higher concentration of conjugated linoleic acids than Canchim bulls (0.86 and 0.59%, respectively). On the other hand, the loin back fat of Canchim bulls had higher concentrations of estearic (17.07%) and linoleic acids (2.40%) and polyunsaturated fatty acids than Nellore bulls, that showed values of 13.47 and 1.44%, respectively. The Nellore and Canchim loin back fat presents significant amounts of beneficial fatty acids to human health. Levels of 40 and 60% of concentrate in the diet did not alter the fatty acids composition of loin backfat.
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The aim of this study was to evaluate the response of dopamine in the growth hormone secretion (GH) during Nellore heifer's sexual maturation. The animals were randomly assigned into two experimental groups: Sulpiride group (dopamine D-2 antagonist, 0.59 mg/kg, S. C.) and control group (saline solution S. C.) at 8, 12 and 16 months of age. Blood samples were collected every 15 min for 10h after drug injection. Growth hormone was quantified by RIA, sensitivity (0.25 ng/mL) and intra and inter-assay variation coefficients were 15% and 17%, respectively. GH concentration was higher in sulpiride group than control group at 8 mo (10.1 +/- 0.38 ng/mL vs 4.3 +/- 0.34 ng/mL; P < 0.05) and 12 mo of age (9.46 +/- 0.35 vs 3.74 +/- 0.19 ng/mL; P < 0.05). In sulpiride group GH average concentration was greater at 8 and 12 mo compared to 16 mo of age (10.10 +/- 0.38 ng/mL and 9.46 +/- 0.35 ng/mL vs 4.87 +/- 0.35 ng/mL; P < 0.05) respectively. There was no difference between groups (P > 0.05) in total GH secretion area, total peak area and maximum peak amplitude. These results suggested an inhibitory dopamine effect on GH secretion in pre-pubertal Nellore heifers that decreases according to age.
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We evaluated the effect of additives the basis of propolis and monensin on ingestive behavior (grazing -GRA, rumination lying -RLY, rumination in foot -RFO, rumination -RUM; idleness lying -ILY, idleness in standing -IDS, idleness -IDL, walking -WAL, posture standing -POS, posture lying -PLY, intake of supplement and water -ISW) of heifers in Tifton 85 grazing. The treatments were: no additive (NAD); propolis - PRO (33.24 mg animal-1 of total flavonoid in apigenin), and monensin -MON (100 mg animal(-1)). Were used five heifers treatment(-1) for evaluation of ingestive behavior during 12 hours of total valuation, which was divided into three periods. Used a factorial design into 3 x 3 for evaluation of ingestive behavior as a function of the evaluation periods. Were utilized three paddocks of 2.9 acres of grass Tifton 85. The additives and mineral supplement (50 g animal(-1)) were provided with 200 g of corn meal to 17 hours. For all activities of the ingestive behaviors observed the effect of period on the time spent on of different activities. The activities of GRA and ISW were higher in the third period (15hours to 19hours) compared to the first period (7hours at 11hours). For IDL and PLY, there was a higher time in minutes for heifers treatment with PRO in the period of 7hours at 11hours, compared to other treatments (NAD and MON). Thus, it is concluded that the use of the additive based on propolis enables sodium monensin replacement, to heifers maintained on pasture without changing eating behavior as well as providing greater idleness during the day the without affecting animal performance.
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The recombinant bovine somatotropin (rbST) at first, had its widespread use in dairy cows in order to increase milk production. Currently, it has been studied frequently and use their influence both in bovine milk, such as cutting. Its production has been an evolution to the science, using bacteria to produce recombinant DNA. Most authors that have studied and obtained positive results, such as increasing the number of ovarian follicles larger than five millimeters, among others. Its action takes place directly on the ovary, follicles, corpus luteum, the granulosa cells, oviduct, myometrium, endometrium and placenta, where they were found receptors, or indirectly through the release of insuline like growth factor-1 (IGF-1). Therefore, the objective of this work is to explain the importance of bST in bovine as well as the usefulness of this, its mechanism of action and the benefits it can bring when combined with other biotechnology, such as superovulation, embryo transfer, synchronization of estrus, and others
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The acceptance of biotechnology for the most equine breeders association had a significant effect in the horse industry, gaining popularity around the world, because the increasing on the genetic gain, allowing the use of sub fertile mares and stallions with high genetics value on reproduction. The embryos in vitro production of human and cattle has been used with success, however in vitro embryo production is not efficient in the horse, as oocyte transfer (OT) and intracytoplasmatic sperm injection (ICSI). The oocyte transfer has been used especially in subfertile old mares presenting reproductive pathologies as: endometrite, cervical and uterine adhesions, blocked oviduct, perineal laceration and ovulation failures. During oocyte recovery process, the oocytes must be collected from immature follicles that need be matured in vitro or in vivo matured oocytes from pre-ovulatory follicles through the transvaginal aspiration guided by ultrasound. The recovered oocyte is transferred to a previously inseminated recipient mare, through the flank laparotomy. The intracytoplasmatic sperm injection (ICSI) is a procedure of in vitro fertilization that needs only one sperm that is aspirated and injected inside the oocyte. The oocytes used, can be from mature and immature follicles. Fresh, cooled and frozen semen can be used, because the procedure not requires a functional sperm. The use of Piezo drill resulted in a breakthrough the pellucid zone, allowing the vibration per minute provided in the sperm injection pipette, a major result of cleaved oocytes, due to a better sperm injection in the oocyte. The embryo transfer can be straight inside the oviduct, as also transcervical transferred after embryo culture produced in vitro. In conclusion both procedures (OT and ICSI) are effective to be used on equine assisted reproduction, getting results even lower than expected, but satisfactory from animal genetically superior
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With the increasing development of the brazilian sheep production, the producer was forced to achieve higher production rates. The use of artificial insemination has been shown as an important biotechnological tool in animal breeding. Among the various existing techniques, the superficial cervical insemination with fresh semen is demonstrating fertility rates between 70 and 80% (AISEN, 2008), in addition to its applicability, it does not require sophisticated equipment or manpower to highly specialized implementing these plans greater possibility in your job to maximize reproduction and greater dissemination of superior genetic material on the property. This study aims to address aspects of artificial insemination with fresh semen in sheep and its applicability in commercial herds biotechnology as a tool in assisted reproduction
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The Doppler ultrasound allows the assessment of blood flow and the differentiate vessels according to each spectral pattern, location and organ that irrigate, helping the examinations and disease diagnosis. The main methods used are Pulsed Doppler, Color Doppler and Power Doppler. In Brazil veterinary medicine, it shows progress since 1990, but its use is limited by the equipment high cost, the need for operator experience and patient cooperation. There are studies in obstetrics and reproduction of dogs and cats, such as evaluation of the testicular vasculature, including the use of contrast material, and attempts to evaluate prostate in healthy dogs or pathological conditions (cancer and testicular torsion , orchitis and benign prostatic hyperplasia; estrous cycle monitoring, evaluation of irrigation in follicles and corpus luteum, uterus and breasts (mammary tumors) in bitches; monitoring pregnancy from the assessment of maternal, fetal and placental hemodynamics, both in dogs as in cats, and aspirations for early detection of pregnancy in dogs. However, new studies are still required, given the lack of these species, especially cats
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Haddadus binotatus é uma espécie endêmica de Mata Atlântica e ocorre desde o sul de Pernambuco até o Rio Grande do Sul. Apesar da sua ampla distribuição pouco se conhece da história natural dessa espécie. Haddadus binotatus apresenta desenvolvimento direto e ovos são depositados sob a serapilheira ou sob troncos caídos. Há dimorfismo sexual, sendo as fêmeas maiores do que os machos. O objetivo desse estudo é conhecer os padrões reprodutivos de populações de H. binotatus no continente e em ilhas do litoral do estado de São Paulo. Os objetivos específicos são: 1) avaliar as diferenças morfológicas entre populações de H. binotatus entre ilhas e entre ilhas-continente, 2) avaliar se há dimorfismo sexual em cada população, e 3) comparar os padrões reprodutivos entre populações insulares e continentais. Neste estudo, foram utilizados exemplares de H. binotatus, depositados na coleção de Anfíbios (CFBH), do departamento de Zoologia, Instituto de Biociências, UNESP, Campus de Rio Claro. Os exemplares são provenientes de uma localidade no continente (São Sebastião) e três ilhas (Couves, Queimada Grande e Ilhabela). Os exemplares provenientes das ilhas, com exceção daqueles da Ilha das Couves, foram maiores do que os da Juréia. Houve dimorfismo sexual em todas as populações, sendo as fêmeas maiores. As populações insulares apresentam número de ovócitos menor do que a população do continente (Juréia). O número de ovócitos semelhante aos da população da Juréia foi registrado para uma população em Minas Gerais, reforçando o padrão de que populações insulares têm desovas menores. No entanto, não houve diferença no tamanho dos ovos. As diferenças encontradas para as populações insulares podem ser resultado de recursos mais limitados como espaço e alimento, pelo tamanho das presas e/ou ausência de predadores. Este estudo preliminar representa... (Resumo completo, clicar acesso eletrônico abaixo)
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The age which heifers reach puberty depend on factors like genetics, environment and nutrition. Puberty in heifers can be defined as the onset of reproductive competence, the ability to ovulate a fertile oocyte with an estrous behavior and development of a corpus luteum with normal lifespan. The metabolic signals that trigger puberty are not yet fully defined. In Brazil, where most beef cattle are zebu, the age at puberty is very advanced, mainly these animals are feed with a poor diet. Many researches are trying to discover the metabolic signals that trigger puberty and anticipate better economic return in breeding farms. It has been demonstrated that the cascade of endocrine events that culminate in puberty can be hastened by an alternative management scheme that involves increased nutrient intake between 3 and 7 months of life. Different diet concentrations, different products and by-products have been used in research to achieve puberty early (less than 300 days of age). The hormonal induction of puberty, especially with the use of progestagens, has been developed in heifers as an alternative tool to improve reproductive efficiency in herds, increasing the amount of pregnant heifers in breeding season
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The dairy sector has undergone considerable economic losses due to low fertility rates due to adverse effects of heat stress on reproduction of cows. Genetic selection for increased production, coupled with the expanding dairy to tropical areas of the planet, and global warming has further aggravated the problem of heat stress. The effects of heat stress are multifactorial and act directly or indirectly at various levels of reproductive tissues, resulting in low fertility of cows, which in practice, results in reduced reproductive efficiency in the property, reducing the producers’ profit. Some strategies related to breeding biotechnology such as fixed-time artificial insemination, embryo transfer and use of BST, can minimize these effects and improve the reproductive efficiency of the herd