الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 160 |  |  |
| | | from | 160 | | |
Abstract
The present work was carriedout in Cairo police mounted
department stud, El-Basateen Camp in Cairo. Using 17 native mares aged 6-12 years old. All females under the present experimental condition were observed to show the beginning and end of the breeding seasons. The length of follicular and luteal phases and the whole estrous cycle in native mares were calculated for the 1st, 2nd 3rd and 4l cycle that observed from the beginning until the end of the breeding season. This was done using a teaser male to detect estrous mares.
Rectal examination of the females were dose monthly during the
nonbreeding season as well as during estrus, early and mid diestrus, during the breeding season for cyclic mares.
Blood samples were collected from all mares monthly during the
nonbreeding season and once during estrus, early luteal and mid luteal from the beginning of breeding season until the end of it for cyclic mares. Plasma progesterone profile was assayed in all collected samples during the non breeding and breeding seasons.
The present results indicate that the breeding season in native mares started at September and ends at February, the length of the follicular phase, luteal phase and whole estrous cycle significantly increased during the 1st cycle (14.31, 27.08 and 41.39 days respectively) and sometimes the 2~’ cycle (7.09, 27.73 and 34.82 days respectively) than that recorded in the 3rd cycle (4.57, 17.57 and 21. 57 days respectively) and the 4th cycle (5.67, 21.67 and 27.33 days respectively). Also there was an increase in
the size of right ovary in mares having large ovary suspected to be had corpora lutea, the smallest size of right ovary of mares under examination were found for females having active ovary during October, there was a marked increase in average size of right inactive ovaries, active ovaries during both follicular and luteal phases and large ovaries suspected to be had corpora lutea than the left ones, there was significant increase in the size of right large ovaries than the left ones. Also in our investigation, we recorded the length of the uterine
horns were significantly increased in mares with large ovary suspected to be had corpora lutea than in those having inactive ovaries during the non breeding season as well as those having active ovaries during lutea~ phase,
there was a significant reduction in the length of the uterine horns was observed in females had active ovaries during follicular phase, there was nonsignificant variation in the length of both right and left uterine horns in our investigation.
There were significant increase in plasma progesterone concent
ration in mares had large ovaries suspected to be had corpora lutea in different months and seasons (12.44 - 17.88 ng /ml) than other mares under investigation followed by mares had active ovaries during mid luteal phase (8.17 - 11.72 nglml) and then mares had active ovaries during early
luteal phase (1.73 - 4.66 ng/ml). The minimum values of plasma progesterone concentration observed in mares had active ovaries during follicular phase (0.43 - 0.95 nglml) and females with inactive ovaries (0.28 - 4.41 ng/ml) in different
months and seasons of the year. from the present study, it could be concluded that, Native Egyptian mare breeding throughout the year but less or no frequent in summer according to the green fodder consumed, the first, estrus, diestrus and estrous cycle were more longer than other cycles, the estimation of plasma progesterone concentration in mares could be used as an indicator for ovarian activity during breeding and non breeding seasons.