[Evaluation of the oxidative status in calves within 3 days of birth]

Background: Oxidative stress reflects an imbalance between the reactive oxygen species [ROS] and a biological system's ability to readily detoxify the oxidative agents. Disturbances in the normal redox state of cells can cause toxic effects through production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA

Objectives: The purpose of this study was to evaluate the oxidative status in calves within 3 days of birth

Methods: Twenty calves from Zagros dairy farm were selected. Blood samples were collected from the jugular vein at 0 [before administration of colostrum], 24, 48 and 72 hours after birth for measurement of serum levels of TBARS, Superoxide dismutase and catalase

Results: The results indicated higher levels of serum malondialdehyde concentration at birth that subsequently decreased at 24 and 48 hours after birth [p<0.05]. There were lower levels of serum concentration of catalase at birth that followed by increasing in it at 24 and 48 hours after birth [p<0.05]. Also, the concentration of superoxide dismutase was lower at the birth that subsequently increased at 24 hours after birth [p<0.05]

Conclusions: Based on this study, it seems that antioxidant capacity of calves has been increased within 3 days of birth. Improvement of oxidative status in calves could be due to gradual increasing of their antioxidative capacity and also beneficial effects of colostrums

Evaluation of dysrhythmias and myocardial biomarkers in high and low-yielding dairy cows

Cardiovascular system is a very important organ that plays a vital role in tissue function. In farm animals, the growth and high milk production depends on function of cardiovascular system. Cardiovascular health in high and low-yielding dairy cows was investigated. Fifty 4-year-old high- yielding Holstein dairy cows and fifty 4- year-old low- yielding Holstein dairy cows were used in this study. Electrocardiogram was recorded by a base- apex lead, and blood samples were collected from the jugular vein for the measurement of cardiac biomarkers [CK [Creatine Kinase], CKMB [Creatine Kinase-Myocardial Band], LDH [Lactate Dehydrogenase], and AST [Aspartate Aminotransferase] and troponin I]. Cardiac dysrhythmias were detected more in low- yielding Holstein dairy cows [62%] compared to highyielding Holstein dairy cows [46%]. The cardiac dysrhythmias that were observed in low- yielding Holstein dairy cows included sinus arrhythmia [34.7%], wandering pacemaker [22.45%], sinus bradycardia [18.37%], sinus tachycardia [10.20%], atrial premature beat [2.04%], sinoatrial block [2.04%], atrial fibrillation [8.16%], and atrial tachycardia [2.04%]. The cardiac dysrhythmias were observed in high- yielding Holstein dairy cows, including sinus arrhythmia [86.95%] and wandering pace maker [13.05%]. Also, notched P wave was observed in highand low- yielding Holstein dairy cows, 30% and 14% respectively. The amount of cardiac biomarkers in the low yielding cows was significantly higher than that of the high yielding cows. Further more, there was not any detectable significant difference of serum concentration of total CK between the high and low- yielding Holstein cows. Despite significant differences in cardiac biomarkers and based on the normal range of cardiac biomarkers in both groups, the increase in cardiac dysrhythmias in low- yielding Holstein dairy cows may be metabolic and electrolyte disorders

Evaluation of pathogenic serovars of Leptospira interrogans in dairy cattle herds of Shahrekord by PCR

Leptospirosis is an important zoonotic disease caused by Leptospira interrogans. Leptospirosis leads to economical losses in dairy farm industry. The objective of this study was to evaluate the pathogenic serovars of Leptospira interrogans in dairy cattle herds of Shahrekord by PCR. Two hundred samples [100 urine and 100 blood] were collected from 100 cows randomly and delivered to the laboratory. Samples were stored at -20 °C. DNA was extracted and purified from the plasma and urine samples and concentrated on diatoms in the presence of guanidine thiocyanate [GuSCN]. PCR products were detected and identified as Leptospira by ilumination of the expected size of DNA bands after staining of the agarose gel with ethidium bromide gels. PCR products were purified and sequenced. The results showed that 28% of urine samples and 23% of plasma samples were contaminated. The major serotypes were Icterohaemorrhagiae [50%] and Pomona [37.5%]. The urine samples of 17 cows were positive for Leptospira without positive plasma samples. This indicated that these cows are reservoirs in dairy herds of Shahrekord and dangerous for human health. The plasma samples of twelve cows were positive for Leptospira without positive urine samples. Leptospira serotypes can be maintained in relatively dry regions and must be considered when dealing with leptospirosis in dairy farms of Shahrekord and human health

[Chemical composition and antibacterial effects of rosmarinus officinalis L essential oil with lysozyme on listeria monocytogenes]

Rosmarinus officinalis L. as a member of the Lamiaceae family and lysozyme as a natural antibacterial agent is important in food microbiology, because of its characteristics. The aim of the present study was to determine the chemical composition and anti-listerial activity of Rosmarinus officinalis essential oil [REO] alone and in combination with lysozyme for enhancement of anti-listerial activity of both substances. Rosmarinus officinalis L. was purchased from a local grocery store at Shahrekord and was identified by the Institute of Medicinal Plants, ACECR. The air-dried aerial parts were subjected to hydrodistillation using a Clevenger apparatus to obtain essential oil and yielded oil was analyzed by GC/MS. Antibacterial activity [on basis of Minimum Inhibitory Concentration [MIC] of REO was studied separately and in combination with unheated lysozyme [L] and heat-treated lysozyme [HTL] on Listeria monocytogenes at different pH [5, 6 and 7] by a micro-broth dilution assay. The collected data were analyzed by SPSS software. In the current study, 98.05% of constituents of the essential oil were identified. The major components were alpha-pinene [14.06%], 1, 8-cineole [13.62%], verbenone [11.2%], camphor [10.51%], borneol [7.3%], 3-octanone [7.02%], camphene [5.46%] and linalool [5.07%]. The inhibitory action of REO was stronger at lower pH especially 5 [MIC=225 micro g/mL]. Inhibition by L at pH 5 was 640 micro g/mL but no inhibition was seen at pH 7. HTL resulted in more effective inhibition than L, especially at pH 5 and heat-treatment 80°C [MIC: 160 micro g/mL]. Combination of L + REO and particularly HTL + REO was led to enhancement of bacterial inhibition. It was concluded that REQ by the identified chemical composition was effective alone or in combination with L or HTL on Listeria monocytogenes as a food-borne pathogen