الفهرس 
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Abstract
Objectives: Evaluate the effect of administration of GnRH analogue (Receptal) at the time mating of New Zealand White rabbit does that mated on different mating postpartum days (0, 5 and 10 d) in relation to the physiological status of rabbit does as well as on the ovulatory response, and yield, quality and measurements of embryos.Methods: Total of 48 rabbit does sexually mature and 10 bucks New Zealand White were used in the present study and does were equally divided into two groups (n=24). Does in the first group were injected with 1 ml saline solution per doe (control), while does in the second group were intramuscularly injected at mating with GnRH analogue (0.25 ml Receptal) per doe (treated), does were divided into 3 sub-groups (n=8) and mated on days 0,5 and 10 postpartum. After parturition, kindling rate, litter size at birth, litter size of live bunnies at birth and weaning was recorded and the viability rate was calculated, also. Plasma progesterone (P4) concentration was determined at 0,7,14,21,28 days after mating. After 72 h from performing the hormonal injection and the natural mating four does from each sub-group was randomly selected and slaughtered and recorded; ovaries, fallopian tubes and uterine horns (uteri) on the right and left sides were removed and weighed. Also, embryos were evaluated morphologicall and serum progesterone (P4) concentration was determined. Number of follicles, hemorrhagic follicles, corpora lutea (CLs) were recorded or doe then, relative ovarian weight to LBW, total number of follicles and ovulation rate were calculated number of recovered embryos and then embryo recovery rate was calculated. Embryos were morphologically measured including thickness of mucin coat and zona pellucid as well as diameter of intra-zonal and the total diameter of embryos.Results: The effect of GnRH treatment was not significant of all reproductive performance, physiological organs and measurments of embryos of rabbit does. However, the present results showed a tendency of increase of rabbit does treated with GnRH as compared to controls was significantly higher for does mated on day 10 postpartum then for those mated on 0 day postpartum and those mated on 5 days postpartum.Conclusion: Injection of rabbit does with GnRH at a level of 0.25 ml/doe on day 10 postpartum improved in vivo reproductive performance of rabbit does and these finding was indicated in in vitro study by increasing yield, quality of produced embryos. Therefore, using GnRH may increase does raising profitability of NZW does.