Abstract
Multiple Ovulation and Embryo Transfer (MOET) in cattle, a component of Assisted
Reproductive Technologies (ARTs), is greatly adopted for genetic upgradation in animals by
increasing selection intensity in dams, reducing generation interval and increasing accuracy of
selection. This study was carried out to evaluate the reproductive efficiencies of the cows,
superstimulation to yield embryos and finally production of offsprings following embryo
transfer (ET). Reproductive potentialities of the cows were studied to monitor Vaginal Electrical
Resistance (VER) patterns, endocrinological profiles and ovarian follicular dynamics during
oestrous cycles of the cross-bred cows. The donor cows were superstimulated by strategic
application of pregnant mare serum gonadotropin (3000IU of PMSG) (Folligon®, Intervet
International, Boxmeer, The Netherlands) and porcine follicle stimulating hormone (400mg of
pFSH) (NIH-FSH-P1, Folltropin®-V, Bioniche Animal Health, Belleville, Ontario, Canada) to
follow up the embryo yield quantitatively and qualitatively. The transferable embryos were
subsequently transferred into suitable recipient cows to observe the pregnancy rates under
different recipient factors such as breeds, progesterone (P4) application, synchronizing
strategies, ovarian follicular sizes during oestrus, VER patterns, and haematobiochemical level
during the day of transfer. The data were carefully recorded and organized for statiscal analyses
using IBM® SPSS® version 22. Expression of the VER and the hormonal profiles (oestrogen and
progesterone) were significantly fluctuated (p<0.05) from day to day and stage to stage of
oestrous cycle. The lowest VER (186.67±12.54 ohms), lowest progesterone (1.04±0.00ng/ml) and
highest oestrogen (3.09±0.02 pg/ml) values were found during the day of oestrus; and the
inverse phenomena were recorded during the luteal phases with minimal fluctuations. A
positive statistical correlation between VER and progesterone but negative relationship was also
observed between VER and oestrogen during the cycle. Both 2 and 3 wave pattern of oestrous
cycle were found in cows over study of ovarian follicular dynamics. Variability in embryo
productions ranging from 0 to 18 were evident in the present study on superovulation.
Superovulatory responses of the donors treated with 3000IU of PMSG were better in Shahiwal
crosses compared to Holstein-Fresian and Jersey cross-bred donors; number of transferable
embryos, Grade 1 and 2 embryo yielding were statistically significant (p<0.05) among different
breeds along with the development of cystic ovarian conditions. Donors treated with 400mg of
PFSH (Folltropin®-V) and synchronizing device showed variable superovulatory responses
such as higher number of embryo recovery (9.82±1.26), transferable embryos (9.10±1.16) and
recovery rate (66.05±3.45) in Holstein-Fresian crosses than those in Shahiwal and Jersey crosses,
although the development of CL (14.00±0.79) was more in Shahiwal crosses. Number of embryo
recovery, Grade 1 and 2 embryo production were significantly varied (p<0.05) among the
different breeds. Embryo production in donor cows treated with 400mg of pFSH excluding the
application of synchronizing device showed an impressive outcome in different experimental
groups (No GnRH on D0, GnRH on D0 and GnRH at random stage of oestrous cycle groups)
(D0=Day of oestrus). Number of detectable CL (14.00±0.79), recovered embryos (9.14±0±.51),
transferable embryos (8.00±0.49) and recovery rate (64.33±4.90) were higher in donor cows
treated with GnRH on D0, and these were significantly differed (p<0.05) each other except in
detectable CL. The overall pregnancy rate was 53.1%, and the higher pregnancy rates were
closely related to synchrony of recipients (63.3%), cross-bred (54.8%), P4 treatment (71.4%),
largest follicular size (69.2%), lowest VER during oestrus (173.33±1.97 ohms), highest VER
during ET (299.987±3.42 ohms), higher blood concentrations of protein (6.58±0.11 g/dl),
cholesterol (198.51±4.07 mg/dl) and phosphorus (4.74±0.05 mg/dl). MOET in cattle of
Bangladesh context is new but feasible under various circumstances with some limitations, and
repeated practices could be a potential way to alleviate such limitations and achieve maximum
benefits.