Induction of ovulation using repeated doses of sulpiride, a dopamine antagonist, in ewe lambs
Date
2023Metadata
Show full item recordAbstract
This study aimed to test the hypothesis that sulpiride can increase the concentration
of circulating gonadotropin that can promote puberty in pre-pubertal
ewe lambs.
Here, 12 1–3-
year-
old
Merino rams and 60 7–9-
month-
old
Merino sheep were included
in the study. The sheep were randomly divided into sulpiride (n = 30) and control
(n = 30) groups. The sulpiride group was subcutaneously injected with 0.6 mg/
kg sulpiride twice daily (morning and evening) for 9 days. During these 9 days, blood
samples were taken from the sheep before drug administration and at 4 h after every
drug administration. The number of ovulating animals in the sulpiride group was significantly
higher than that in the control group (90% vs. 32%). No oestrous signs were
observed in either group during ram release. Further, there were no differences in
the levels of mean follicle-stimulating
hormone in the two groups based on treatment
(p = .2), time (p = .3) or treatment-by-
time
interaction (p = .3). After sulpiride
administration, the luteinizing hormone (LH) levels of the sulpiride group rapidly increased
and remained stable for a long time, whereas physiological LH fluctuations in
the control group remained unchanged. Within-group
changes in terms of LH concentrations
were significant for both groups (p < .001), whereas LH pulse frequency was
significantly different between the sulpiride group (p = .03). Therefore, it is concluded
that sulpiride can be used as a non-steroidal
alternative to stimulate pre-pubertal
ewe
lambs and sheep during anoestrus.