Interaction of Environmental Lighting, Age, and Genetic Background Influencing the Estrous Cycle
An outstanding characteristic of the DA strain and its fertility problem was the suspension of cyclic estrus early in adult life among segregated females and replacement of cycles by more or less continuous vaginal cornification. This persistent vaginal “estrus” when well established was associated with the presence in the ovaries of prominent vesicular follicles and the absence of corpora lutea. Cycling DA females also rapidly developed the condition when exposed to continuous illumination. In addition, there were certain seasonal influences relating to the length of daily illumination as detailed below.
KeywordsEstrous Cycle Environmental Lighting Continuous Illumination Vaginal Smear Prolonged Estrus
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