Relationship of daylength and prolactin to resumption of reproductive activity in anestrous ewes.
نویسنده
چکیده
منابع مشابه
Effects of photoperiod and feeding level on perirenal adipose tissue metabolic activity and leptin synthesis in the ovariectomized ewe.
Leptin is secreted by adipose tissue and plays a pivotal role in regulating both body energy homeostasis and reproductive function in rodents. Among livestock, sheep is a seasonal breeder whose reproductive period is initiated by short daylength. We show that plasma leptin and leptin gene expression in perirenal adipose tissue were decreased when ovariectomized Lacaune ewes were exposed to shor...
متن کاملEffects of melatonin infused into the III ventricle on prolactin, beta-endorphin and luteotropin secretion in ewes during the different stages of the reproductive cycle.
Secretion of all the pituitary hormones undergoes marked circadian and seasonal changes. The rhythmicity of these changes is controlled by the circadian pacemaker system and the pineal gland transmitting daylength information to the neuroendocrine axis via the secretion of melatonin. This article presents data on the effects of the short-term melatonin administration into the third brain ventri...
متن کاملMelatonin patterns in ewes maintained under skeleton or resonance photoperiodic regimens.
Two experiments were designed to study the mechanism for measurement of daylength by ewes. 1) Two groups of 8 adult ewes were exposed for more than one year to either 16L:8D (long days) or 7L:9D:1L:7D alternated every 3 months with 8L:16D (short days). Ovulatory activity was followed during the total duration of the experiment and compared to that of a third group of 8 females under simulated n...
متن کاملPoor reproductive response of anestrous Suffolk ewes to ram exposure is not due to failure to secrete luteinizing hormone acutely.
Twenty Polypay-sired ewes (Group P) and 14 Suffolk ewes (Group S) were bled at 48-h intervals for 10 d beginning on April 6, 1989, and the serum was assayed for progesterone to determine which ewes were anestrous; 9/20 Group P ewes were anestrous, compared with 14/14 Group S ewes (P less than .001). Catheters were placed into the jugular vein of anestrous ewes from both breed groups (eight of G...
متن کاملEffects of FSH treatment in seasonally anestrous ewes on egg production, retrieval, and quality for use in in vitro fertilization procedures
Through the use of assisted reproductive technology (ART), we will be able to extend the use of genetically superior animals, and perhaps increase the number of offspring. These technologies include such procedures as estrus synchronization, superovulation, artificial insemination, embryo transfer, in vitro fertilization (IVF), and cloning. Because they exhibit seasonal breeding and multiple ov...
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ورودعنوان ژورنال:
- Journal of animal science
دوره 50 2 شماره
صفحات -
تاریخ انتشار 1980