English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Two groups of mares were exposed to an abrupt, artificial increase or a natural increase in daylength. In both groups, mean LH pulse frequency increased with time of year and was accompanied by a reciprocal decrease in LH pulse amplitude. A non-pulsatile pattern of LH secretion was observed in some mares sampled close to the day of ovulation. Maximum mean LH pulse frequency and the onset of the breeding season occurred earlier in those mares exposed to an abrupt artificial increase in daylength. In blood samples collected frequently, mean serum LH concentrations increased in relation to time of year. However, during 60 days before ovulation, when LH pulse frequency increased, mean daily serum LH values only increased on Day -3 before ovulation. The magnitude of the periovulatory LH rise was greater before the second than the first ovulation of the breeding season. These results support the hypothesis that, in the mare, a photoperiod-induced seasonal alteration in LH pulse frequency and/or amplitude may play a role in the onset of the breeding season.

Changes in LH pulse frequency and amplitude in intact mares during the transition into the breeding season