This experiment was conducted to study the effects of different sources of zinc (Zn) on blood metabolites and balances of some minerals in lambs. In the first part, 20 6-7-month-old lambs were randomly allotted to four treatments including (1) basal diet containing 22.47 mg Zn/kg DM without supplementary Zn (control), (2) basal diet + 40 mg Zn/kg DM as ZnSO4 (ZnSO4 40), (3) basal diet + 20 mg Zn/kg DM as Zn-proteinate (Zn-Pro 20), and (4) basal diet + 40 mg Zn/kg DM as Zn-proteinate (Zn-Pro 40). Blood samples were taken on days 0, 28, and 65 before morning feeding. In the second part, four lambs from each treatment were randomly transferred to metabolic cages to evaluate the effects of different sources of Zn on N, Zn, Fe, and Cu retentions. This trial consisted of 18 days, with the first 12 days as the adaptation period followed by 6 days of sample collection. The results of this study showed that the source of Zinc had no significant effect on the analyzed parameters. Average daily gain and feed efficiency were improved by Zn supplementation (P < 0.05). Daily feed intake, plasma glucose, Fe and Cu concentrations, serum total antioxidant capacity, red blood cell count, packed cell volume, and hemoglobin concentration did not differ significantly between treatments (P > 0.05). Plasma Zn concentration, alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BALP) activity, and white blood cell and lymphocyte count differed significantly between control and Zn-supplemented groups (P < 0.05) as Zn supplementation improved these parameters. Nitrogen, Fe, and Cu retentions did not differ between treatments (P > 0.05). Zinc retention showed a significant difference between control and Zn-supplemented groups (P < 0.05), but there were no significant differences among the Zn-supplemented groups. The results of this study show that Zn supplementation improved performance and zinc retention in lambs. However, there were no significant differences between zinc sources used in this study.

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ABSTRACT:The objective of this study was to develop a superovulatory program based on synchronization of follicular waves with GnRH which could be applied regardless of the stage of the oestrous cycle. 36 heifers were subjected to this experiment and GnRH (Cystorelin, 200 µg) was applied between Days 0 and 7 (n = 15), 8 and 12 (n = 8) or 13 and 20 (n = 13) of the oestrous cycle. Four days after GnRH treatment, all follicles ≥ 6 mm of heifers (n) were either punctured (n = 21) or left intact (n = 15). All heifers were superstimulated from Day 6 to Day 10 after GnRH treatment with 320 mg Folltropin-V. In parallel, 21 heifers were superstimulated in a conventional manner (Days 8 to 12) and were used as controls. The homogeneity of follicular inventories among Stage-groups occurred within 4 days of GnRH treatment for follicles ≥ 7 mm but only 2 days after follicular puncture for follicles 4 to 6 mm. In response to the follicular puncture, the mean number of follicles 4 to 6 mm increased in heifers of the punctured group (P < 0.01). Following the superstimulation, the follicular (P < 0.01) and ovulatory (P < 0.01) responses were higher in the punctured group than in the nonpunctured group. The in vivo production of transferable embryos in the punctured group was similar to that of the nonpunctured group but it was lower (P < 0.01) than in heifers of the control group. In conclusion, results from the present study indicate that regardless of the stage of the oestrous cycle, the homogeneity of follicular inventories following the follicular synchronization is obtained using GnRH treatment and follicular puncture. The in vivo production of embryos was severely compromised in the present study with heifers. Causes of such reduction in the in vivo production of embryos are still unknown.

The effects of organic selenium (Se) alone or combined with organic chromium (Cr) on semen quality and metabolites and blood antioxidant status was evaluated during the summer in rams. Fourteen Mehraban rams (2-4 years, BSC 2.5-3.5, initial body weight 70.14 ­kg) were divided in to four groups (n=4) and two levels of Se (0 and 0.6 mg/ram/day, inactive dry Se-yeast) were tested at two levels of Cr (0 and 1 mg/ram/day, Cr-methionine) in a completely randomized design with 2×2 factorial layout for 60 days. Body weight changes and scrotal circumference (SC) were recorded fortnightly. Semen quality and metabolites, rams libido, spermatozoa motion characteristics, blood ferric reducing ability (FRAP) and thiobarbituric acid reactive substances (TBARS) were measured during the experiment. Body weight, dry mater intake and SC were not affected by treatments. Chromium alone increased FRAP, libido and sperm linearity and combined with Se increased spermatozoa viability, membrane integrity and decreased semen glucose and alkaline phosphatase activity (P≤0.05). Main effect of Cr tended to increase EV (P=0.095). Abnormal spermatozoa and TBARS decreased by Cr, Se or by their combination. Selenium alone had higher sperm concentration compared to its combination with Cr (P≤0.05). Average path velocity was numerically higher by Se alone and curvilinear velocity was lower by combined with Cr, but the difference was not significant (P>0.05). In conclusion, Cr and Se supplementation of rams during the summer improved semen quality and blood antioxidant status. However, co-supplementation of Cr and Se had no more additional effects on studied parameters.

ABSTRACT:The objective of this study was to develop a superovulatory program based on the synchronization of follicular waves with GnRH which could be applied regardless of the stage of the oestrous cycle. In this experiment, GnRH was given to 30 heifers in lactation between Days 0 and 7 (n = 13), 8 and 12 (n = 12), 13 and 16 (n = 5) of the oestrous cycle. Twenty-four heifers were used as controls and did not receive any GnRH. All follicles ≥ 6 mm were punctured 4 days after GnRH treatment in treated animals and between Days 8 and 12 of the oestrous cycle in control heifers. Two days after the follicular puncture, all heifers were superstimulated with 160 mg Folltropin-V given twice daily over 2 days. Oocytes were collected 42 h after the last FSH treatment. The oocytes were subjected to IVM/IVF and the developmental competence of embryos was compared. In vitro production of embryos was affected only by the stages of the oestrous cycle when the GnRH treatment was given and not by the GnRH treatment. No difference (P > 0.1) in the mean number of oocytes, cleavage and embryo production was noted between the control animals and the animals treated with GnRH in the late phase of the oestrous cycle. The mean number of blastocysts was higher (P < 0.05) in heifers treated with GnRH in the mid and the late phase of the oestrous cycle than in the early phase. In conclusion, the in vitro production of embryos was compromised in the present study with heifers following the follicular synchronization with GnRH. This procedure is advantageous for the in vitro production of bovine embryos since the spontaneous oestrus is eliminated. However, more investigations are needed to increase the competence of oocytes obtained following this procedure.