ABSTRACT
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
ABSTRACT
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