This experiment aimed to study the combined effect of each of the follicle size, insulin-like growth factor (IGF-I), glucose and hormones (growth hormone (GH) and luteinizing hormone (LH)) on different phases of in vitro nuclear maturation of Awassi sheep oocytes. Follicles diameters were divided into two main groups: small follicles (SF): 1-2 mm and large follicles (LF): >2 mm. The levels (μg/ml) of Insulin-Like Growth Factor (IGF-I), GH, LH and glucose (mM) were determined according to two increasing shared concentrations (A:5,5,1 and 50; B:10,5.5,5 and 100 respectively). The maturation events were monitored at 7-time intervals (0,3,6,9,12,21 and 27 hours). Before incubation (0 - hour time interval), the oocytes in SF group outperformed their counterparts of LF group in the germinal vesicle phase (92.45% Vs 74.46%; p=0.01). Down to the 6- hour time interval, the oocytes in B solution achieved the highest rates (24.52%; LF group),  After 9 hours of incubation, the differences appeared clearly in the prometaphase -1(p=0.05) as half of the number of oocytes in B solution reached the stage (53.84%; LF group), the rates did not exceed 31.37% (A solution; SF group). In the 12 - hour time interval, the pro -metaphase-1 rates across the four groups reached the values :34.00% (A solution; SF group), 40.00% (B solution; LF group), 53.84% (A solution; SF group) and 58.49% (B solution; LF group) respectively. Upon 21- hour time interval, oocytes across the different groups showed a significant difference in metaphase-I (p=0.01) with the superiority of oocytes of B solution (33.96%; LF group). At the 24- hour time interval, the rates of oocytes involved in the metaphase-II were sub-intermediate and ranged between 20.00% and 36.00% without statistical significance. The final time interval (27- hours of incubation) showed a significant difference in the rates of the metaphase-II (p=0.002), as the oocytes of B solution showed a great superiority (84.61%; LF group). It is concluded from this study that the maturation of oocytes derived from large follicles (>2 mm) in a mixture of IGF-I, GH, LH (μg/ml) and glucose (mM) with the levels 10,5.5,5 and 100 respectively led to a significant increase in the rates of metaphase-II.

The participatory relationship among the follicle size, follicle stimulating hormone (FSH), and cysteamine (antioxidant agent) contribute to the production of embryos characterized by abundance and good quality. The aim of this study was to evaluate the efficacy of FSH, cysteamine and follicle size on <em>in vitro</em> embryo production of Awassi sheep oocytes. Follicles sizes were determined into two groups: small follicles (1-2 mm) and large follicles (&gt; 2 mm). Oocytes were matured across two increasingly shared levels of FSH and cysteamine: A (40 ng/ml + 50 μM) and B (60 ng/ml + 100 μM). Results of the bilateral interaction showed significant differences across the follicle size (large follicles group) and the maturation treatment (B medium) in the rates of fertilization (highest value: 67.51%; p= 0.02), cleavage (highest value: 65.41%; p= 0.01), 2-16 cell stage (lowest value: 2.29%; p= 0.0001), blastocyst stage (highest value: 44.82%; p= 0.04), down to morula stage arrest (lowest value: 55.17%; p= 0.04) and Type I embryos (highest value: 52.87%; p= 0.03). Likewise, matured oocytes of small follicles group (B medium) attained the highest rate of morula stage (56.60%; p= 0.03). No significant differences were observed in Type II and Type III embryos. In order to obtain high yields of good quality embryos, it is advised to add FSH and cysteamine with levels of 60 ng/ml and 100 μM respectively to maturation medium of ovine oocytes obtained from follicles with a diameter &gt; 2 mm.

In this study, the contemporary comparison method (CC) of half-sibs relation was used to estimate the breeding values of Holstein-Friesian sires for 305 -day milk yield (305-DMY) and basic components of milk traits, 409 records of cows that are daughters of ten sires in eight Syrian dairy farms where used. Result of the study showed differences in the estimated breeding values(ccEBVs), where the E Sire achieved the highest value of 305-DMY trait (254.47 kg), while the B Sire achieved the highest value of milk protein percentage (MPP), milk fat percentage (MFP)and milk lactose percentage (MLP) traits (0.822 %, 0.857 %and 1.09% respectively). According to their sires, daughters of E Sire outperformed the counterparts in the 305-DMY (p = 0.001), MPP (p = 0.001) and MFP (p = 0.04) traits (5701.44 kg, 3.55%, and 3.88% respectively). According to source of farm, daughters in Farm 5 achieved the highest value of 305-DMY trait (p=0.04) and daughters in the seventh farm achieved the highest value of MPP trait (p=0.007), the values were 5403.48 kg and 3.54 % respectively. Values of heritability (h2) for the traits of 305-DMY, MPP, MFP and MLP were 0.33,0.54,0.43 and 0.47 respectively. Most of genetic and phenotypic correlations coefficients were approaching to zero except the genetic relation between MLP and MPP and phenotypic relation between MFP and MPP (0.88 and 0.84 respectively).

The use of cryoprotectants in vitrification would reduce the critical damages to the embryos, thus increase the survival rates. This research was conducted in the laboratory of reproductive biotechnology at the faculty of Agriculture of Aleppo University.  The study aimed to evaluate the viability and survivability of early Syrian Awassi embryos under the influence of dimethyl sulphoxide (DMSO) and ethylene glycol (EG) following vitrification. Embryos were vitrified in three solutions of cryoprotectants (A: DMSO (3 ml), B: EG (3 ml), and C which was composed of a combination of DMSO (1.5 ml) and EG (1.5 ml)). After thawing, embryos that had been vitrified in C solution achieved the highest rates of cleavage (P&lt; 0.01) comparing with A and B solutions for 2-16 cell stage (50.00% Vs 30.77% and 36.36%), morula (9.00% Vs 44.44% and 40.00%) and blastocyst stage embryos (92.86% Vs 58.33% and 50.00%) respectively. Down to the hatching blastocyst stage, 2-16 cell stage vitrified embryos in C solution achieved an encouraging rate comparing with A and B solutions (39.20% Vs23.08% and 22.73% respectively). The rates of arrested embryos decreased significantly (P&lt; 0.05) after thawing across the three solutions especially the morula and blastocyst stage (0.00 and 3.70% respectively) (C solution). No significant differences were observed in the three types of embryos across all stages and solutions despite the large range among these rates. Given the apparent benefit of the participatory effect of cytoprotectants, it is advised to use a mixture of DMSO and EG (1:1) in vitrification of ovine embryos.

In this study, two experiments were conducted to study the effect of both the follicle size and the cryoprotectants dimethyl sulfoxide (DMSO) and ethylene glycol (EG) on the main phases of nuclear maturation (Experiment I), cleavage stages and embryo quality (Experiment II) of Awassi sheep oocytes. Follicles were classified into two groups: small follicles (SF) (1-2 mm) and large follicles (LF) (> 2 mm). Oocytes were vitrified in three solutions: A (30% DMSO), B (30% EG) and C (15% DMSO and 15% EG). In Experiment I, the resulting vitrified-thawed oocytes in solution C achieved the best rates after the control group (fresh), respectively as the rates of maturation, germinal vesicle (GV), metaphase II(M-II), arrest, and lyses were 85.71% (P = 0.04), 8.33% (P = 0.02), 72.92% (P = 0.04); LF group, 15.25% (P = 0.04), and 5.08% (P = 0.04); SF group, respectively. In Experiment II, the same group of oocytes achieved the best rates after the control group, as the rates of fertilization, cleavage, 2-16 cell, Type3, blastocyst, and Type1 embryos were 63.28% (P = 0.001), 57.46% (P = 0.001), 40.38% (P = 0.04), 38.46% (P = 0.04); LF group, 30.00% (P = 0.01), and SF group 36.67% (P = 0.001), respectively, while the vitrified-thawed oocytes in A solution (SF group) reached the highest rate of Type 2 embryo quality (58.06%; P = 0.01). No significant differences were noticed in the germinal vesicle breakdown (GVBD), metaphase I (M-I) and morula stage. Vitrification of oocytes obtained from follicles with a diameter of more than 2 mm in a cocktail solution of DMSO (15%) and EG (15%) led to a significant increase in the yield and quality of the resulting sheep embryos.