RESUMO
The effects of addition of gonadotrophin-releasing hormone (GnRH) to a progesterone plus oestradiol-based protocol and timing of insemination in Holstein cows treated for timed AI (TAI) were evaluated. Cows (n=481) received a progesterone device and 2mg oestradiol benzoate. After 8 days, the device was removed and 25mg dinoprost was administered. Cows were allocated to one of three (Study 1; n=57) or four (Study 2; n=424) groups, accordingly to ovulation inducer alone (Study 1; oestradiol cypionate (EC), GnRH or both) or ovulation inducer (EC alone or combined with GnRH) and timing of insemination (48 or 54h after device removal; Study 2). In Study 1, the diameter of the ovulatory follicle was greater for GnRH than EC. Oestrus and ovulation rates were similar regardless of ovulatory stimuli. However, time to ovulation was delayed when GnRH only was used. In Study 2, cows treated with GnRH or not had similar pregnancy per AI (P/AI) 30 days (41.5% vs 37.3%; P=0.28) and 60 days (35.9% vs 33.0%; P=0.61) after TAI. TAI 48 and 54h after device removal resulted similar P/AI at 30 days (40.3% vs 38.5%; P=0.63) and 60 days (33.8% vs 35.1%; P=0.72). Thus, adding GnRH at TAI does not improve pregnancy rates in dairy cows receiving EC. The flexibility of time to insemination enables TAI of a large number of cows using the same protocol and splitting the time of AI.
Assuntos
Indústria de Laticínios/métodos , Estradiol/análogos & derivados , Sincronização do Estro/métodos , Hormônio Liberador de Gonadotropina/administração & dosagem , Inseminação Artificial/veterinária , Indução da Ovulação/veterinária , Animais , Bovinos , Estradiol/administração & dosagem , Sincronização do Estro/efeitos dos fármacos , Feminino , Inseminação Artificial/métodos , Indução da Ovulação/métodos , Gravidez , Taxa de Gravidez , Fatores de TempoRESUMO
The hobo transposable element can occur under three forms in the Drosophila genome: as a complete element (also called canonical), as internally deleted copies, or as hobo-related sequences (relics). Some evidence indicated that canonical elements and internally deleted copies are recent acquisitions of Drosophila genomes, while the "relics" are old components, normally degenerated and immobile. Here we present the characterization of a hobo-related sequence, found in the genome of a hypermutable strain of D. simulans, which insertion into the white locus raised a de novo white mutation. It is a shorter hobo related element presenting, overall, roughly 18% of divergence at the DNA level from the canonical hobo, with many indels that make clear this element is defective. However, its ITRs and flanking regions are extremely conserved. This is the first hobo "relic" showed to be mobilizable. We suggest, and point up some evidences, toward the idea that this sequence could have been mobilized by the canonical element. The presence of a similar "relic" element in D. sechellia allows us to suggest that these elements have been maintained mobilizable since the time of divergence between these species.
Assuntos
Proteínas de Drosophila/genética , Drosophila/genética , Genoma de Inseto , Homologia de Sequência do Ácido Nucleico , Transposases/genética , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Evolução Molecular , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Mutação , Transposases/metabolismoRESUMO
Fetal monitors that feature autocorrelation have recently been introduced. This paper discusses autocorrelation and describes how it extracts periodic signals from a noisy background. An example of its performance under clinical conditions demonstrating advantages and limitations is discussed.