الفهرس 
ACKNOWLEDGEMENT
Reproductive performance of ewe lambsOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
This study was carried out on 25 native ewe lambs clinically healthy. The body weight was ranged between 27 and 33 Kg with an average age ranged between 8 and 12 months. The ewe lambs were housed under the experimental sheep farm condition of Animal Reproduction Research Institute (ARRI),AL-Ahram, Giza. Ewe lambs were fed 3.0 Kg Egyptian clover (Trifoliumalexandrinum) plus 250 gm. concentrate in winter, while in summer the Egyptian clover was substituted by 2.0 Kgdarawaper head daily.
The animals divided into 5 groups,each group has 5 ewe lambs. Each group was containing 2 ewe lambs from 8 to10 months of age and weighing from 27 to 30 kg and 3 ewe lambs from 10 to 12 month of age and from 30 to 33 kg body weight.Group (1) served as control,Group 2(Flushing), received vaginal sponges impregnated with 60 mg medroxy progesterone acetate(MAP), for 14 days during this periodthe ewe lambs fed 3 kg Barseem plus 500 gm concentrate, per head daily, Group 3 (PMSG), received vaginal sponges impregnated with 60 mg(MAP) for 14 days, on the day of sponge removal; each animal injected with PMSG (250 IU, I/M),Group 4 (GPG), the ewe lambs received 1.25 mlReceptal (0.5 μgGnRH) I/M on day 0, Seven days later, ewe lambs injected with0.5 ml Estromate (125 μg. PGF2α) I/M, after 48 hours, animals treated with the second dose of GnRH.Group 5 (PGF2α), received two injections of 0.5 mlEstromate on days 0 and 7, respectively.After 72 hours from the second dose of PGF2α, ewe lambs were injected with 0.2 ml hCG.
Heat detection was performed daily by visual observation and using three fertile rams in good health condition, with an age of 2 to 3 years, for breeding, during the expected days after the removal of the sponges. The fertile ram was introduced after 24 hours of the sponge removal and After 72 hours of PGF2α injection, once every 3 hours till the end of the estrus. Ewe lambs stand firmly to the ram considered to be in heat. Other signs were also recorded.Trans-rectal ultrasound scanning was also performed to pregnancy and follicular diameter.
Blood samples
Blood samples were collected by venipuncture from jugular vein into vaccutainer tubes left to be clotted and centrifuged at 5000 r.p.m for 10 minutes, and then serum was obtained and stored at -20Cᵒ till hormonal assay.Blood samples were collected at intervals; on day of treatment, at theend of treatment and once daily successive the three days after 24 hours from treatment end. Animals which detected pregnant and confirmed by ultrasonography; blood samples were taken monthly till parturition.
Ultrasound examination (U/S) of ewes was performed all over the time as follow:-
At 14 days before the experiment, to be sure that ovaries and the reproductive tract of the ewe lambs are normal and functioning.
After the end of treatment (for three days). To follow up the follicle size.
After 30 days from the end of treatment to detect pregnancy by observing placentomes, fetal fluids and embryos.
The results obtained from the analysis of the data can be summarized as follows:
Reproductive performance in ewe lambs:
Onset of estrus and its duration (hours)in ewe lambs.
Onset of estrus was not recorded for control, while PMSG treatment had a highly significant (P< 0.01) effect on onset of heat (hours); where it accelerates the ewe lambs to come into heat earlier than Flushing and GPG treatment(37.70±2.63 vs 75.25±1.89 and 74.20±3.09, respectively).
Estrus duration of treated groups increased compared with that of control one, particularly that of PMSG group which had the most obvious increment (P<0.05) in estrus duration than that of control, flushing, GPG and PGF2α+hCGgroups (35.90±2.59 vs 21.00±2.00, 31.62±1.72, 31.90±2.00 and 29.00±00 hours, respectively).
Estrus response, Conception and lambing rates in ewe lambs.
Flushing, PMSG and GPG treatments had significant effect on percentage of estrus response (P˂ 0.01) compared with control and PGF2α+hCG treatments, the corresponding values were 80%, 100% and 100% vs 40% and 20%, respectively. The conception rate revealed that Flushing, PMSG and GPG treatment had significantly higher (p<0.01) values than that of control and PGF2α+hCG groups, the corresponding values were 60%, 100% and 100% vs 40% and 0%, respectively. Lambing rates of Flushing, PMSG and GPG groups were higher (P<0.01) than those of control and PGF2α+hCG (60%, 100% and 80% vs40% and 0%, respectively.
Follicular Diameter by Ultrasonography.
There was no effect of treatmentson follicular diameter after one day fromtreatmentend. The follicular diameter (mm) after two days of the treatment end of treated groups showed higher (P<0.01) values than that of control group (2.76±0.23, 2.27±0.32, 3.20±0.35, 3.25±0.61 vs 0.63±0.07), respectively. However, all treatment groups were found to have a significant increase (P<0.05) in the follicular diameter (mm) on both ovaries after the end of treatment within three days, the diameters were 4.35±0.36, 3.94±0.26, 3.37±0.24 and 3.90±0.49 for Flushing, PMSG, GPG and PGF2α+hCG, respectively, the corresponding value for control group was 2.11±1.05 mm.
Gestation period and lamb’s weight
There were no-significant changes among groups in gestation period; it was ranged between 151.50±1.28 and 154.00±1.48 days. Lamb’s weight of PMSG group tended to be higher than those of other treatments,flushing, GPG and control one (3.29±0.15vs 2.88±0.19, 2.75±0.19and 2.75±0.23, respectively).
Serum progesterone concentration (ng/ml) in ewe lambs
At the start of treatment and around the time of estrus
Flushing group had significant (P<0.01) effect on serum progesterone concentration (ng/ml) at treatment end compared to PMSG, GPG and PGF2α+hCGtreatments (0.30±0.03vs 0.12±0.04, 0.14±0.02 and 0.04±0.02, respectively). However, serum progesterone concentrations (ng/ml) after one day of estrus beginningwas higher (P<0.05) PMSG treatmentthan that of other treatments control, Flushing, GPG and 5 PGF2α+hCG(0.58±0.20 vs 0.10±0.00, 0.14±0.04, 0.24±0.07 and 0.28±0.10, respectively). At day 2 after estrus beginning serum progesterone level (ng/ml) was higher (P<0.01) in PMSGtreatment compared the other groups control, Flushing, GPG and PGF2α+hCG (0.80±0.19vs 0.10±0.00, 0.24±0.09, 0.30±0.10 and 0.22±0.15, respectively).
During gestation period in ewe lambs.
Serum progesterone concentration around first month of gestation period had higher (P<0.05) values in Flushing and PMSG treatmentthan those of control and GPG groups(3.87±0.78 and 3.78±1.05vs 2.00±.30and 1.40±0.54, respectively).However, there were no-significant changes in serum progesterone levels among treatments during 2nd, 3rd, 4th and 5th months of gestation in ewe lambs.
Conclusion.
from this study we concluded that, using intra-vaginal sponges impregnated with medroxy-progesterone acetate plus pregnant mar serum gonadotropin (PMSG) and gonadotropin releasing hormone plus prostaglandin F2α (GPG) protocol, may be improved reproductive performance in native ewe lambs.