Document Type : Original Article
Authors
1
Faculty of Agriculture, Department of Animal production, Assiut University.
2
Faculty of Agriculture, Department of Animal Production, El-Azhar University.
3
Animal Reproduction Research Institute (ARRI), AL-Ahram, Giza, Egypt.
Abstract
The influence of gonadotropin releasing hormone (GnRH), Pregnant Mare Serum
Gonadotropin (PMSG) and human Chronic Gonadotropin (hCG) on some reproductive responses of
Egyptian ewe lambs was evaluated. Twenty five animals (aged 8 – 12 months and weighed 27 - 33
Kg) were divided into 5 groups (5 ewe lambs each). Group (1) served as a control, Group (2), received
vaginal sponges impregnated with MAP (60 mg medroxy progesterone acetate) for 14 days, during
these period, animals fed 3 kg Berseem (Trifolium alexandrinum) plus 500 gm concentrate/head/day.
Group (3), received vaginal sponges impregnated with (60 mg, MAP) for 14 days, on the day of
sponge removal; each animal injected by PMSG (250 IU, I/M). Group (4) animals received 1.25 ml
Receptal (0.5 μg, GnRH) I/M, on day 0, Seven days later, ewe lambs injected with 0.5 ml Estromate
(125 μg. PGF2α) I/M, after 48 hours, animals treated with the second dose of GnRH. Group (5)
received two injections of 0.5 ml Estromate on days 0 and 7, respectively, after 72 hours from the
second dose of PGF2α ewe lambs were injected 0.2 ml hCG. Heat detection was performed and transrectal
ultrasound scanning also performed to confirm estrus, pregnancy and follicular diameter. The
results revealed that, administration of PMSG (group 3) reduced the interval to estrus (the onset of heat
/hours) significantly (p< 0.01) compared with control and other groups. Regarding conception and
lambing rates, group 2, 3, & 4 had significantly (P˂ 0.01) affected than group 1 & 5. Follicular
diameter (mm) tended to increase significantly in treated groups than the control one. Non-significant
change was observed among groups in gestation period, while group 3 showed an increase in lamb's
weight than the other treatments. Results suggest that, tested hormones have effect on selected
reproductive responses in Egyptian ewe lambs while administration of PMCG (Group 3) has the best
response compared to other hormonal treatments.
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