This study aimed to investigate the effects of nano and organic selenium on ovarian activity,
fertility rate, and progesterone hormone levels in Ossimi ewes. Thirty ewes were treated with
intra-vaginal sponges impregnated with medroxyprogesterone acetate (40mg) for 14 d and
simultaneously assigned randomly to three groups. The 1st group ewe served as control (CG).
Ewes in the 2nd and 3rd groups were treated orally with organic selenium 3 mg/ewe and Nanoselenium
0.2mg/ewes during intra-vaginal sponges (IVS) treatment SeG and N-SeG, respectively.
The ovarian activity was monitored using an ultrasonic device, and serum samples were harvested
for progesterone measurement. The results revealed that ewes in SeG and N-SeG groups
had a significantly (p<.05) higher number of small and large follicles after 48 h of IVS withdrawal
than in the CG, respectively, on the left ovary. Also, the N-SeG group had a larger diameter
of the Corpus luteum on both ovaries’ sides than CG, respectively, at the same time.
However, the diameter of large follicles on both ovaries was significantly (p<.05) larger in the
N-SeG after 72 h of IVS withdrawal than in SeG and CG. The ewes in N-SeG and SeG came in
oestrus earlier (p<.05) than those in CG, and the oestrus durations were longer (p<.05) than
that recorded in ewes of CG. The oestrus response and fertility rate were higher (p<.01) in
N-SeG and SeG than in CG. Moreover, the progesterone concentrations were significantly higher
(p<.05) in the N-SeG and SeG after 48 and 72 h of IVS withdrawal than in the CG. Also, the
recorded serum progesterone concentrations in the included ewes non-significantly differed
between groups during the first four months of pregnancy. It could be concluded that using
nano and organic selenium can improve the quality of ovarian follicles and CL function and
enhance the fertility rate in Ossimi ewes.