Background: This study was conducted to evaluate the relationship between oxidative stress and some blood parameters in different number of quarters affected with and without sub-clinical mastitis (SM). Methods: A total of 50 lactating Holstein dairy cows were used in the study. The study groups were as follows; Group 1 (negative test results and no SM), Group 2 (SM in one quarter), Group 3 (SM in two quarters), Group 4 (SM in three quarters) Group 5 (SM in four quarters). Milk samples were obtained from the infected quarters for both Somatic Cell Count (SCC) measurement and bacteriological growth/bacterial identification. Blood was collected for analysis of oxidative stress parameters (total oxidative capacity and total antioxidant capacity) and some blood parameters (glucose, total cholesterol, total bilirubin, aspartate aminotransferase [AST], alanine aminotransferase [ALT]). Result: Somatic Cell Count (SCC) was significantly lower in Group 1 than in Groups 2, 3, 4 and 5 (P less than 0.001). Glucose and total cholesterol levels were significantly higher in Group 5 than in Groups 1, 2, 3 and 4 (P less than 0.001). A significant difference was determined between all groups in respect of AST and ALT activities (P less than 0.001). The Total Oxidative Capacity (TOC) and oxidative stress index value (OSI) levels were significantly lower in Group 1 than in Groups 2, 3, 4 and 5 (P less than 0.001), while Total Antioxidant Capacity (TAC) levels were significantly higher (P less than 0.001). In conclusion, it was found that oxidative stress and blood-biochemistry values are significantly affected in dairy cows with sub-clinical mastitis.

Background: This study was conducted to compare the changes in oxidative stress levels with some trace elements in blood serum in healthy bitches and bitches with transmissible venereal tumor (TVT). Methods: A total of 40 bitches were used in the study. According to the genital organ examinations, healthy bitches constituted the control group (n=20) and those with venereal tumors constituted the TVT group (n=20). Total oxidant status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI) were determined spectrophotometrically. In addition, some serum trace element levels such as magnesium (Mg), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn) and selenium (Se) were measured using an ICP-MS analysis device. Result: The serum Se, Mg and Zn levels were lower in the TVT group compared to the control group (p less than 0.01) and serum Fe and Cu levels were higher in the TVT group than in the control group (p less than 0.01). Serum TOS and OSI levels were higher (p less than 0.001) and serum TAS levels were lower (p less than 0.001) in the TVT group compared to the control group. The study results showed that oxidative stress is high in bitches with TVT, and in parallel with this, changes occur in the amount of certain trace elements that are associated with oxidative stress.