Ultrasonographic Study of Follicular Dynamics in Normal Cyclical and Superovulated Murrah Buffaloes
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Date
2008
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Publisher
TANUVAS, Chennai
Abstract
Ovarian follicular development in buffalo is a dynamic sequence of wave like
organized event and understanding the ovarian follicular wave pattern would enable
us to implement the technologies like estrus synchronization, multiple ovulation
embryo transfer programme etc., more effectively.
The study was designed to monitor the normal and superovulatory estrous
cycles in Murrah buffaloes. Four pluriparous normal cyclical Murrah buffaloes
maintained at Livestock Farm, Veterinary College and Research Institute, Namakkal,
Tamil Nadu, were utilized. A total of eight normal (control) and eight superovulated
cycles were studied ultrasonographically for the follicular wave pattern and ovulatory
response.
In control group, the ovaries were examined ultrasonically daily throughout
the estrous cycle. Then the experimental animals were randomly divided into 2 groups
as group I and II comprising of 2 buffalos in each group. Superovulation was induced
by injection of Follicle Stimulating Hormone (FSH) twice daily for four days in
tapering dose (total dose 400 mg) and a single injection of 2000 IU equine chorionic
gonadotropin (eCG) in group I and II buffaloes, respectively starting on day 10 of
estrous cycle. Prostaglandin F2α (PGF2α) was injected at 48 and 72 h of the initiation
of superovulatory treatment. Ovarian structures were monitored daily for five days
from the day of initiation of superovulatory treatment to the day of superovulatory
estrus and 5th day after superovulatory estrus.
In the present study, 62.50 per cent of the normal cycles exhibited 2-wave
cycles, while the remaining had 3-wave cycles with an interestrus interval of 21.60
± 0.51 and 22.67 ± 0.88 days, respectively.
In 2-wave estrous cycles the waves emerged on day 1.40 ± 0.24 and
11.80 ± 0.37. The dominant follicle of the first and second waves reached the
maximum size of 12.00 ± 0.32 and 14.20 ± 1.02 mm on day 11.80 ± 0.37 and 21.60
± 0.47, respectively of the estrous cycle. The growth phase and growth rate of the first
and second wave dominant follicles were found to be significantly not different.
In 3-wave estrous cycles, the waves emerged on day 0.67 ± 0.33, 8.33 ± 0.33
and 16.67 ± 0.33. The first, second and third wave dominant follicles reached the
maximum size of 11.83 ± 0.44, 11.67 ± 0.44 and 13.33 ± 0.67 mm on days
8.33 ± 0.33, 16.67 ± 0.33 and 22.67 ± 0.88, respectively.
In superovulated cycles the overall mean (± SE) number of follicles during the
four days in group I and II were 4.25 ± 0.48, 5.75 ± 0.48, 8.00 ± 1.47 and 9.25 ± 1.97
and 5.00 ± 0.82, 7.00 ± 0.71, 8.50 ± 1.32 and 9.25 ± 1.65, respectively. On the day of
superovulatory estrus, the overall mean number of follicles differed significantly from
9.25 ± 1.97 to 10.25 ± 0.75 in group I and from 9.25 ± 1.65 to 8.50 ± 0.65 in group II.
A mean number of 1.00 ± 0.00 and 1.25 ± 0.25 dominant follicles in group I and II
were found on the day of initiation of superovulatory treatment and it had no
significant relationship on the superovulatory response.