HORMONAL APPROACHES TO AUGMENT FERTILITY AND FECUNDITY IN SHEEP
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Date
2001
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University of Agricultural Sciences, Dharwad
Abstract
The cyclic ewes were supplemented with progesterone, GnRH and
during the luteal phase of the cycle following breeding. The supplementation of
progesterone and hCG during the luteal phase of cycle did not register any significant
difference in the levels of progesterone in relation to the untreated control group.
However, these levels were marginally higher in treated ewes on the contrary mean
plasma following GnRH therapy was 2.45 ± 0.33 as against 1.38 ± 0.07 ng/m! in the
control group. The ewes that were confirmed pregnant registered significantly higher
level of progesterone on day 23 of the cycle in relation to day 0 and the respective
levels were 3.01 ± 0.33 and 0.31 ± 0.05 ng/ml. The lambing percentage in GnRH
treated was 83.33 followed by 66.67 in hCG; 50.00 in late luteal progesterone
supplementation and 16.67 in early luteal progesterone supplemented ewes. The cost
of therapy ranged between Rs. 7.80 to 46.90 per ewe. The supplementation of graded
doses of eCG on day 9 of the cycle combined with PGF2 alpha on day 11 and fixed
doses of hCG at estrus were tried to improve fertility and fecundity in sheep. The
mean plasma estradiol 17-beta on day of natural estrus ranged between 3.78 + 0.58
to 6.42 ± 1.26 as against 7.57 ± 1.93 to 10.14 ± 2.36 pg/ml at superovulation estrus.
The mean plasma progesterone levels at natural and superovulation estrus ranged
between 0.27 ± 0.02 to 0.31 ± 0.07 and 0.30 ± 0.06 to 0.43 ± 0.04 ng/ml respectively.
The ewes supplemented with 200 to 400 IU of eCG on day 9 registered significantly
higher levels of progesterone on day 10 while this increase was marginal in the ewes
supplemented with 200 and 300 IU of eCG. The mean plasma progesterone levels
following PGF2 alpha dramatically came down to basal level within 24 hr of PGF2
alpha administration. The pregnant group of ewes registered significantly higher level
of progesterone on day 23 of the cycle in relation to day of estrus and the respective
levels were 2.26 ± 0.23 and 0.34 ± 0.04 ng/ml. The lambing percentage was only
33.33 in the untreated control ewes as against a range of 57.14 to 85.71 in the
combined eCG, PGF2 alpha and hCG therapies. The cost of these hormonal
treatments ranged between Rs. 94.60 to 184.20 per ewe.
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Citation
No . of references 208