Abstract
Ovarian response, quality and survival rate of embryos in different genetic groups
of Bangladeshi cattle treated with Pregnant Mare's Serum Gonadotrophin
(PMSG) and Follicle Stimulating Hormone (FSH) and Multiple Ovulation and
Embryo Transfer (MOET) related traits were studied. Five different dose levels of
FSH and PMSG were used to study the ovarian response and quality of embryos.
A total of 60 donor cows and 108 recipient cows/heifers constituted the
experimental population of Local (L), Pabna (Pb) and Friesian x Local (F x L)
cattle. Selection of donor and recipient were made on the basis of good health,
known pedigree and reproductive superiority with at least twice normal cycling of
behavioral estrous. Yields of corpus luteum (CL), recovered embryo (RE) and
transferable embryo (TE) differed significantly (p<0.01) among themselves with
different dose levels of FSH and PMSG in Local, Pabna and F x L genetic groups.
The effect of FSH and PMSG on the quality of embryos were found in significant
except in the excellent quality (p<0.05) indicating little effect of different dose
levels of FSH and PMSG on the yield of quality of embryos. Morphological
developmental stages of recovered embryos in three different genetic groups were
found to be statistically insignificant. There was no significant difference
survival rate of embryo either using FSH or PMSG. Embryo survival rate was
higher in cows (50.00%) than those in heifers (48.83%). Survival rates relating to
quality of embryos in excellent, good, fair and poor were found 52.38%, 46.66%,
in
38.88% and 0.00% respectively. Survival rates relating to the morphological
developmental stages of embryos differed significantly (p<0.05) and were found
45.00%, 48.64%, 47.82% 44.44% and 10.00% when used morula, compact
morula, blastocyst, expanded blastocyst and hatched blastocyst respectively.
Embryo survival rate was found to be higher in cows than in heifers when the
embryo was transplanted in the basal part or within 3-5 cm from the internal
bifurcation of the uterine horn and central part or 5-10 cm down to the uterine
horn from the internal bifurcation and the survival rates in cows and heifers were
found 48.64%, 50.00% and 43.47%, 40.00% respectively. There were no
significant differences in embryo survival rates with or without epidural
anesthesia prior to embryo transplantation. Embryo survival rates did not differed
significantly in recipients with either artificially or naturally synchronized estrous.
It was found that the embryo survival rates varied significantly (p<0.05) with the
degree of asynchrony level of recipient's estrous from '0' to +' or ‘- 24 hours to
the donor's estrous and the survival rates in recipients were found 35.00%,
48.15%, 51.52%, 36.36% and 47.06% in -24h, -12h, 0h, +12h and +24h
asynchrony levels respectively with the highest at the '0'h and the lowest at the -
24h level. The estimated heritability values for CL, RE and TE were 0.10, 0.04
and 0.03 respectively. Slow but positive genetic trend in MOET related
reproductive traits excеpt in CL in different genetic groups were observed. The
results of the study may be useful in planning and execution of a MOET based
cattle breeding and development program in Bangladesh.