Abnormalities in the oestrous cycle in the mare.

The research article focuses on the various conditions and situations that can interfere with the normal oestrous cycle in mares. It highlights the impact of the season of the year, persistent luteal function, psychological influences, endometritis, multiple ovulation, behavior post pregnancy failure, and granulosa cell tumors on these abnormalities.

Impact of Season on the Oestrous Cycle

• The researchers observed that the time of the year greatly influences the oestrous cycle in mares. Their “breeding season,” as artificially determined, does not fully align with their maximum reproductive efficiency. Hence, the natural breeding pattern could be at odds with imposed cycles, leading to discrepancies in expected fertility.

Persistent Luteal Function and its Effect

• An abnormal persistence of luteal function can disrupt the oestrous cycle. Normally, the luteal phase is a stage of the cycle that should terminate naturally, but when it remains, it might throw the entire process off balance, leading to fertility issues.

The Role of Psychological Factors

• Behavioral activity, which can be influenced by psychological factors, also plays a role in disrupting the oestrous cycle. Stress, for instance, might affect regular hormonal cycles.

Impact of Endometritis on Oestrous Cycle

• The study found that the presence of endometritis, inflammation of the inner layer of the uterus, can interfere with the oestrous cycle. This medical condition may affect the normal cycling of reproductive hormones, potentially leading to abnormal oestrous cycles.

Effect of Multiple Ovulation

• Multiple ovulations can complicate the cycle and result in an abnormal oestrous rhythm. The mare’s system might struggle to manage multiple ovulations at once, leading to unpredictability in the cycle.

Behavior Post Pregnancy Failure

• Behavior following pregnancy failure can also influence the oestrous cycle. The physiological and psychological impacts of a failed pregnancy may cause irregularities in the mare’s reproductive cycle.

Influence of Granulosa Cell Tumours

• Finally, the presence of granulosa cell tumors can impose changes on the oestrous cycle. These tumours, developing from the ovarian follicular cells, can disrupt the normal sequence of hormonal secretion and affect the oestrous cycle adversely.