Results 211 to 220 of about 273,699 (263)
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Reproductive cycle of the elephant
Animal Reproduction Science, 2011The combination of a few factors, including poor captive reproduction, secession of importation from the wild and advances in hormone detection and ultrasonography, has contributed to the current knowledge on the elephant reproductive cycle. Several reproductive features in elephants differ markedly from other mammals.
Thomas B, Hildebrandt +4 more
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Reproductive cycles of marine mammals
Animal Reproduction Science, 2011Marine mammals conform to the general mammalian reproductive system centered on the hypothalamic-pituitary-gonadal axis. Most marine mammals are long-lived and of large body size with lesser reproductive rates than many other animals, a consequence of their interaction with the marine environment where the demands of acquiring resources from the ocean ...
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THE ANNUAL REPRODUCTIVE CYCLE IN MALLARDS
Journal of Steroid Biochemistry, 1983In wild mallard drakes plasma FSH and LH levels were elevated at the height of the breeding season in spring, decreased towards the end of the reproductive phase and were low during the time of photorefractoriness in summer, when the testes were regressed. In contrast plasma prolactin concentrations increased only towards the end of the breeding season
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Steroids pretreatment in assisted reproduction cycles
The Journal of Steroid Biochemistry and Molecular Biology, 2014The objective is to present an overview of trials and appreciate the relevant data on the effect of steroids pretreatment (oral contraceptives, 17β-estradiol and estradiol valerate) in assisted reproduction cycles. The subject of the study is to evaluate the clinical characteristics during steroids pretreatment cycles focused on the prevention of ...
V, Sobotka +4 more
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Reproductive cycles in Tarsius bancanus
American Journal of Primatology, 1986AbstractThe reproductive condition of three pairs of Bornean tarsiers (Tarsius bancanus) was documented for 16 months. Each pair was housed separately under a constant photoperiod (L:D = 11.5:12.5) similar to that in their native habitat. Reproductive cycles of females were monitored visually for 6 months and were then monitored with vaginal smears and
Patricia C, Wright +2 more
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1987
Human females undergo sexual cycles which prepare the reproductive system for pregnancy; these cycles are controlled by the combined action of the hypothalamus, pituitary, ovary and uterus. The ovarian cycle is regulated as a direct response to pituitary gonadotropins, i.e., follicle Open image in new window HORMONAL CONTROL of the FEMALE ...
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Human females undergo sexual cycles which prepare the reproductive system for pregnancy; these cycles are controlled by the combined action of the hypothalamus, pituitary, ovary and uterus. The ovarian cycle is regulated as a direct response to pituitary gonadotropins, i.e., follicle Open image in new window HORMONAL CONTROL of the FEMALE ...
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Cultural change and the reproductive cycle
Social Science & Medicine, 1992What we regard as 'normal' or 'natural' with respect to human female reproductive physiology differs greatly from the reproductive cycle experienced during most of human existence. Frequent ovulatory menstrual cycles really represent repeated abortive reproductive cycles and are unphysiological. A number of medical conditions, some of great importance,
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Reproductive cycles of the domestic bitch
Animal Reproduction Science, 2011Domestic dogs are monoestrous, typically non-seasonal, polytocous, spontaneous ovulators and have a spontaneous luteal phase slightly longer (by approx 5 day) than the 64±1day luteal phases of a 65±1day pregnancy, a phase followed by an obligate anestrus before the next 2-3 week "heat" (proestrus-estrus).
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Reproductive Cycles and Environment
1999In all organisms, reproduction is timed through natural selection to occur during those periods of the year that are most propitious for the survival of both parent and young. According to Baker (1938), these favourable conditions are the “ultimate cause” of a particular breeding season; the “proximate causes” which are another set of factors, initiate
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