Results 151 to 160 of about 70,068 (218)

Seasonal Breeding: Nature's Contraceptive

1980
Publisher Summary This chapter focuses on the seasonal control of fertility. It discusses two aspects in detail—the way in which changes in the secretion of luteinizing hormone-releasing hormone by the hypothalamus controls the activity of the pituitary and testis, and the way changes in day length influence the activity of the hypothalamus.
G A, Lincoln, R V, Short
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Breed Differences in the Breeding Season in Sheep

1985
The literature has been surveyed for evidence of genetic variation in sexual function of rams throughout the year and in the timing of onset and duration of the breeding season in female sheep. The results of studies on the breeding season of several ewe breeds in Ireland are also presented.
J. F. Quirke, J. P. Hanrahan
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Out-of-Season Breeding in Goats

Veterinary Clinics of North America: Food Animal Practice, 1990
Maintenance of winter milk production and the production of meat kids for seasonal specialty markets are two major reasons for out-of-season breeding. Strategies include the manipulation of light cycles and the administration of exogenous gonadotrophins following progestogen priming with either vaginal sponges or subcutaneous implants. A number of does
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Parameters for Seasonally Breeding Populations

Ecology, 1967
Lotka's equations relating the parameters of populations with no seasonal trend in birth rates and Fisher's formula for "reproductive value" are modified to describe populations with restricted annual seasons of birth. The parameters "net reproductive rate" and "mean generation length" provide statistics and dubious utility for populations with ...
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Kisspeptin: A key link to seasonal breeding

Reviews in Endocrine and Metabolic Disorders, 2007
In seasonal species, photoperiod (i.e. daylength) tightly regulates reproduction to ensure that birth occurs at the most favorable time of year. In mammals, a distinct photoneuroendocrine circuit controls this process via the pineal hormone melatonin. This hormone is responsible for the seasonal regulation of reproduction, but the anatomical substrate ...
Florent G, Revel, Laura, Ansel, Paul, Klosen, Michel, Saboureau, Paul, Pévet, Jens D, Mikkelsen, Valérie, Simonneaux   +6 more
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BREEDING SEASONS IN THE GALAPAGOS.

Ibis, 1950
Summary. The Galapagos are on the equator. In the cool and cloudy dry season the south‐east trade wind blows and the cold Humboldt current flows strongly round the islands. In the rainy season, which is very variable but usually lasts from about January to April, the weather is calm, warm and sunny, with periodic heavy rain, while the northern ...
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