Rami Ihsan Al-Timimi, Talib Musa Abdullah, Nazih Wayes Zaid

1Department of Surgery and Obstetrics-College of Veterinary Medicine-University of Baghdad. Baghdad. Iraq.

Abstarct

Seasonality is a major determinant of reproductive efficiency in mares and can complicate breeding
management during transitional periods. This study characterized seasonal reproductive patterns, estrus
behavior, and ovarian dynamics in Arabian mares maintained under natural photoperiod in Baghdad, Iraq.
Ten clinically healthy mares (5-15 years; 9 ± 3 years) were monitored for 12 months. Estrus was detected
by daily teasing and recorded using a standardized semi‑quantitative scoring system. Rectal examination
and transrectal ultrasonography (7.5 MHz) were performed at 15‑day intervals (10‑day intervals in
irregular/prolonged estrus) to evaluate ovarian activity and confirm ovulation. Mares were classified as
true polyestrus (Group A, n=6) or seasonal polyestrus (Group B, n=4) according to winter ovarian activity.
Group B mares exhibited spring transition (March-May), a summer breeding season (June-August),
autumn transition (September-November), and deep winter anestrus (December-February). Estrus
intensity varied among individuals but generally escalated to peak receptivity (+++). Preovulatory follicles
typically reached approximately 3-4 cm, and ovulation occurred 24-48 hr before the end of the follicular
phase (estrus). Ovulation occurred slightly more frequently from the left ovary (53.6%) than the right
(46.4%). These benchmarks provide practical field indicators for reproductive management of Arabian
mares under Iraqi conditions.

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