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Abstract The objective of this study was to evaluate the effect of repeated surgical collection on ovarian response (No. of ovarian structures), quality and recovery rate of embryos recovered and ovarian and genital measurements of New Zealand White (NZW) and the Baladi black (BB) induced to ovulate by GnRH at insemination. Total of 12 the Baldi Black and New Zealand white (NZW) rabbit does (6-7 mo of age and 3.25-3.50 kg LBW) as embryo donors and two fertile bucks, one Baladi black and one NZW (7.5-8 mo of age and 3.5-4.0 kg LBW) were used for natural mating were used to study the effect of repeated surgical collection on quality and recovery rate of embryos recovered from New Zealand White (NZW) and the Baladi black induced to ovulate by GnRH at insemination. The obtained results could be summarized as the following: Number/doe of normal follicles (23.8 vs. 16.6), hemorrhagic follicles (6.6 vs. 4.2) and total follicles (30.4 vs. 20.8) was higher (P<0.05) and ovulation rate was lower (28.3 vs. 42.8%, P<0.05) in BB than in MZW. Number of CLs was 8.9 and 8.6/doe in NZW and Bb, respectively. Number/doe of normal, hemorrhagic and total follicles was not affected by collection number. Number of CLs/doe and ovulation rate increased (P<0.05) by increasing collection number, being 7.6 and 27.1%, 8.8 and 35.6% and 10.0 and 41.3% with the 1st, 2nd and 3rd collection, respectively. Number of unviable embryos/doe (1.9 vs. 1.3), total embryos (7.5 vs. 5.7) and embryo recovery rate (87.0 vs. 64.0%) was higher (P<0.05) in Bb than in MZW. The difference in number of normal embryos/doe was insignificant between NZW (4.4) and Bb (5.6). Number of normal embryos and total embryos/doe and embryo recovery rate was higher (P<0.05) with the 1st (6.2, 7.3 and 96.1%) and 2nd (6.8, 8.3 and 94.3%) collections than with the 3rd collection (1.9, 3.7 and 37%). Number of unviable embryos/doe was 1.1, 1.5 and 1.8 at 3 successive collections. Thickness of mucin coat (101.4 vs. 111.4 µm) and diameter of mass cells (117.5 vs. 125.4 µm) and total diameter of embryo (363.3 vs. 415.3 µm) were lower (P<0.001), while zona pellucida was thicker (26.9 vs. 23.6 µm, P<0.05) in NZW than in Bb. Thickness of mucin coat increased (P<0.05) to 111.5 µm with the 2nd collection and gain decreased (P<0.05) to 102.5 µm with the 3rd collection as compared to 105.2 µm with the 1st collection. Thickness of zona pellucida increased (P<0.05) from 24.1 to 26.3 µm and diameter of intrazonal decreased (P<0.05) from 126.5 to 119.0 µm by increasing collection number up to three times. There were significant differences in ovarian and genital measurements (weight, length and width) due to rabbit breed and the side (right and left). Such results may reflect the save side of embryo surgical recovery for two collections on number of embryos/doe and embryo recovery. |