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The present study was conducted to observe the effect of increased osmolality of basic tris extender supplemented with trehalose and sucrose on post-thawing quality (motility, progressive motility, viability, the rate of acrosome abnormality, total abnormality and membrane integrity) of Markhoz goat spermatozoa. Fresh semen samples were evaluated for motility and sperm concentration. Only semen samples with motility more than 70% and sperm concentration higher than 3×10 9 sperm/ml were used for cryopreservation. In Exp. 1, trehalose (50, 75 or 100 mM) and sucrose (40, 60 or 80 mM) were added to a basic tris diluent. Based on the results of experiment 1, the goal of Exp. 2 was to investigate the combinational effects of the highest and lowest concentrations (T 100 +S 80 or T 50 +S 40 ) of trehalose and sucrose. As the control, semen was diluted and frozen in the tris diluent without trehalose or sucrose. The results in Exp. 1 showed that all evaluated spermatozoa characteristics improved significantly after freezing and thawing (p<0.05) and at the same time the increase of trehalose and sucrose concentrations in basic extenders was seen, with the best results obtained for extenders containing 70 and 100 mM trehalose and 80 mM sucrose. Comparing these results with those of control diluents, the effects of supplementation were significantly (p<0.05) better. In Exp. 2, the results showed no significant differences (p>0.05) between T 100 +S 80 and T 50 +S 40 extenders, but the results of T 50 +S 40 were slightly better than obtained with T 100 +S 80 diluents. Furthermore, the results of this experiment indicated that the sperm characteristics in the isotonic control extender were significantly (p<0.05) lower than examined extenders. In conclusion, the results of this study indicated that goat sperm can tolerate hypertonic trehalose and sucrose solutions better than isotonic control diluents in the freezing period. In particular, these positive effects have been shown for acrosome integrity, which is very important for the fertilization capacity of sperm. The data indicated that addition of trehalose plus sucrose to the freezing extender can be recommended for cryopreservation of goat spermatozoa, but more data is needed on pregnancy rate, acrosome reaction and IVF to ascertain the real effect.

This experiment was conducted to study variations of serum testosterone and seminal characteristics of Markhoz male goats. Blood samples were obtained via jugular vein, and semen was collected by using an artificial vagina from 14 fertile male goats (2–3 years of age), at 15-day intervals starting on 15 July and ending on 30 October 2010 (during breeding and non-breeding season). Semen volume, total sperm (volume×concentration), live sperm (%), abnormal sperm (%) and semen pH were significantly superior during the late summer and early autumn (breeding season). Variation of sperm density, motility and progressive motility was not significant during the sampling period. The results presented show that the lowest and highest levels of lactate dehydrogenase in the seminal plasma were recorded in late October (2.82 U/ml) and in late August (4.81 U/ml), respectively. Moreover, the study indicated that the serum testosterone concentration was higher during late summer and early autumn (p<0.05) than at any other of sampling period. There were negative correlations between volume and sperm density (−0.135, p<0.05), and positive correlations between volume and percentage live sperm (0.224) and percentage progressive motility (0.194, p<0.01). Sperm density was correlated with live sperm (0.200, p<0.05) and progressive motility (0.202, p<0.01). The correlation between live sperm and progressive motility was 0.554 (p<0.01). Furthermore, the results in this study indicated a significant positive correlation between live sperm and LDH (0.450) and a negative correlation between sperm density and LDH concentration (−0.272) (p<0.01). Significant, but positive correlations were found between sperm motility and LDH (0.542) and testosterone concentration (0.522), respectively (p<0.05). In conclusion, this study demonstrated that the best obtained semen was collected in late summer (during decreasing photoperiod) and early autumn (September and October). This also coincides with the natural breeding season of Markhoz goats in Iran.