Conservation of Buck's Spermatozoa during Cooling Storage Period through Cooling Medium Supplementation with L-Carnitine.

This research examined the influence of the addition of L-carnitine (LC) to cooling medium on buck's semen quality during cooling storage periods at 4oC. Semen samples were collected, diluted, assigned into four groups, and received LC (0, 1, 5, and 10 mM LC). The samples were then chilled to 4oC and stores for 48 h. Sperm total motility, progressive motility, viability, lipid peroxidation, membrane integrity, and mitochondrial activity were examined at 0, 24, and 48 h of cooling storage. At time 0 of cooling storage, different treatments showed no impact on the quality of sperm samples (P>0.05). During 24 and 48 h of chilling periods, the supplementation of cooling medium with 5 mM LC presented greater motility, viability, membrane integrity, and mitochondrial activity (P≤0.05), compared to the other groups. Moreover, the treatment of 5 mM LC caused lower lipid peroxidation (P≤0.05) than the other treatments at 24 and 48 h storage times. In conclusion, the supplementation of buck's cooling storage medium with 5 mM LC is a suitable way to protect buck spermatozoa during 24 and 48 h storage against cold-induced structural and functional damages.

Seroprevalence of Neospora caninum Infection in Dairy Cattle in Tabriz, Northwest Iran.

BACKGROUND: The aim of this study was to determine the seroprevalence of antibody to Neospora caninum in healthy and aborted dairy cattle in Tabriz, capital of East-Azarbaijan in northwest of Iran. METHODS: In this cross-sectional study serum samples were collected from 266 healthy and aborted Holestein-Feriesisnc cows from September 2008 to August 2009. The sera were analyzed to detect of antibody against N. caninum using the commercially ELISA kit. RESULTS: Seroprevalence of antibody to N. caninum was 10.5% in Tabriz dairy cattle. Also the abortion rate in all cattle sampled was 33.6% but percentage of seropositive aborted cattle was 18.4%. CONCLUSION: Neosporosis could be one of the possible causes of abortion in dairy cattle in Tabriz and regarding the distribution in dogs as definitive host for the parasite, further studies in dog and cattle are recommended.

Effect of zinc ion on peroxidase activity of serum in cow.

In this study, for clarifying some possible mechanism of zinc toxicity, the effect of increasing amounts of Zn2+ ion on peroxidase activity was investigated in vitro in serum of cow. The H2O2-mediated oxidation of o-dianisidine was used to assess the peroxidase activity. Results show that after preincubation of serum with 0.2-20 mM Zn2+ concentration for 5 min, peroxidase activity was inhibited compared to the control and decreased rapidly with increasing metal concentrations. The enzyme was completely inhibited after 5 min preincubation in 30 mM Zn2+. When the preincubation of serum and Zn2+ was prolonged to 30 and 60 min, the enzymatic activity decreased more rapidly with increasing metal concentration. Extended exposure of the enzyme to lower concentrations of the metal brought about the same effect as shorter exposure to higher metal concentrations.