Evaluation of the hypothalamus-pituitary axis response to exogenous GnRH, estradiol benzoate, And LH during the postpartum period in Nellore cows

The objective was to evaluate when the LH reserve was re-established in postpartum Nellore (Bos indicus) cows by evaluating the response of the hypothalamic-pituitary axis responsiveness to exogenous GnRH or estradiol benzoate (EB). Additionally, we tested the influence of dietary supplementation (SUPL) and calf removal (CR) on the duration of postpartum anestrus. Ninety multiparous lactating Nellore cows were randomly assigned to eight groups. The EB and GnRH groups received 1.0 mg EB (N = 7), and 50 μg lecireline (N = 16), respectively. Additional cows were given the same hormones, and subjected to either nutritional supplementation (EB-SUPL, N = 9; GnRH-SUPL, N = 16), or calf removal at 72 hours after calving (EB-CR, N = 4; GnRH-CR, N = 13). The remaining two groups were the LH (12.5 mg, N = 14) and control groups (saline, N = 11). Hormones were administered weekly from 7 (±5) days postpartum to first ovulation (detection of a CL during a weekly ultrasonographic examination). Blood samples were collected just before and 2 hours (GnRH, LH, and control groups) or 18 hours (EB groups) after hormone or saline (control) administration. Ovulation occurred as early as 15 days postpartum in the GnRH group. The mean ± SEM intervals (days) from calving to first ovulation were EB, 87.7 ± 4.2; EB-CR, 20.3 ± 1.2; EB-SUPL, 60.3 ± 3.2; GnRH, 40.4 ± 2.1; GnRH-CR, 21.0 ± 1.1; GnRH-SUPL, 26.4 ± 1.1; LH, 35.6 ± 1.1; and control, 60.9 ± 2.1. We concluded that there was sufficient LH in the pituitary gland (of Nellore cows) from the second week postpartum to induce ovulation in response to exogenous GnRH. Additionally, calf removal and nutritional supplementation reduced, by 2 to 4 weeks, the interval from calving to an LH increase and ovulation induced by GnRH or EB. © 2013.

Esophageal transit time assessed by magnetic methods: An in vitro feasibility study of the novel alternating current biosusceptometry with 3-axis magnetorresistor

A hybrid magnetic instrumentation to detect a magnetic field from a permanent magnet, and to detect magnetic markers and tracers using alternating current biosusceptometry (ACB) is discussed. The instrument was used to in vitro evaluation of the esophageal transit time. The sensitivity between both magnetic methods was compared, showing sensitivity for in vivo applications. © 2013 Springer-Verlag.

Produção de quimeras embrionárias bovinas mediante a agregação de embriões diploides (Bos indicus) e tetraploides (Bos indicus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comportamento ao cisalhamento da madeira de Eucalyptus citriodora através do ensaio OFF-AXIS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Simulação numérica do comportamento da madeira de Eucalytus citrodora ao cisalhamento através do ensaio de tração Off-Axis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resposta cortisolêmica e sensibilidade ao hormônio adrenocorticotrófico (ACTH) de jundiá (Rhamdia quelen) em exposição sub-letal a agrotóxicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Polymorphism analysis in genes of the somatotropic axis in Nellore cattle selected for growth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Leukotriene B-4/BLT1 Axis Is a Key Determinant in Susceptibility and Resistance to Histoplasmosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Leaf and inflorescence axis anatomy of Brazilian species of Rapateoideae (Rapateaceae, Poales)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Colleters on the inflorescence axis of croton glandulosus (euphorbiaceae): structural and functional characterization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

c ̂-Axis resistivity in graphite-AlCl3 as found by CESR measurements

We report the absolute values of the c ̂-axis resistivity obtained from conduction electron spin resonance (CESR) experiments at various temperatures for a graphite-AlCl3 stage 2 compound. The agreement with d.c. measurements is quite good. The temperature dependence of the c ̂-axis resistivity previously obtained from CESR for graphite-AlCl3 is revised. © 1990.