OXIDATIVE STRESS IN RELATION TO PHYSIOLOGICAL AND PRODUCTIVE CHANGES IN CATTLE

Abstract

Sana Sayed Mostafa Emara: Oxidative Stress in Relation to Physiological and Productive Changes in Cattle. Unpublished Ph.D. Thesis, Department of Animal Production, Faculty of Agriculture, Ain Shams University, 2015. The main objectives of the present study were to determine and evaluate the periods of oxidative stress during pregnancy in crossbred cows (Brown Swiss x Baladi) and its side effects on physiological responses of cows. And also, alleviate oxidative stress in heat-stressed crossbred calves by adding some additives to their diet. The experiments were conducted in the Project of Improving Cattle Production in Nuclear Research Center, Atomic Energy Authority of Egypt, which is located in the desert area of Inshas. This study included three experiments, (A, B and C) as following: Experiment A: The present study was carried out to determine and evaluate the periods of oxidative stress in pregnant cows and its side effect on physiological changes. Twenty multiparous crossbred cows (Brown Swiss x Baladi) were used in this experiment, which included two periods. The 1st period all cows were maintained under mild conditions for 3 months (from mid October 2012 to mid January 2013), the 2nd period all cows were maintained under hot summer conditions for 3 months (from mid June 2013 to mid September 2013), where in each period 5 non-pregnant, cows were used and considered as the 1st group, while in the 2nd group 5 pregnant cows in the 3rd stage of pregnancy (two months before parturition) and continued for one month after parturition were used under the same conditions. In the two periods some oxidant and antioxidant indices and blood components were determined, on days 60, 30, and 3-7 pre-partum, and on days 1 and 30 postpartum. Present results showed a significant (P < 0.01) decrease in antioxidant status, uric acid, Cu, Fe, HDL and progesterone (P4) hormone concentration in cows under hot condition. However, there were a significant (P < 0.01) increase in MDA, lipids profile, kidney and liver function, cortisol and testosterone hormone level were recorded under hot summer conditions. The result in pregnant cows as compared with non-pregnant, indicated a significant gradual decrease (P < 0.01) in antioxidant enzymes activities, uric acid, Cu, Fe, HDL and P4 concentration with the advance of pregnancy until parturition, and then the significant increases in these parameters were recorded until approximated with the normal level on day 30 postpartum, except P4 which recorded a significant sharp decrease. However, a significant gradual increase (P < 0.01) was detected in serum MDA, kidney and liver function, lipids profile, cortisol and testosterone hormone concentrations with the advance of pregnancy until parturition, and then the significant (P < 0.01) decreases were recorded until approximated with the normal level on day 30 postpartum. Also, current results showed a significant interaction between physiological status and season in most parameters. Experiment B: Fifteen male crossbred calves were used in this experiment to study how rosemary (RM) supplementation reduce the side effect of oxidative stress and its relation with growth performance in heat stressed crossbred calves. The animals were maintained under hot summer environmental conditions, and divided into three equal groups, the first group was offered the basal diet as a control group, whereas the second and third groups were fed the same basal diet as in control, in addition to a daily supplement of 3 g and 6 g dried grinded RM / kg concentrate, respectively, which considered as a treated groups, for a period of one month. Current results showed that a daily supplement of 3 and 6 g dried grinded RM / kg concentrate significantly (P<0.01) increased total antioxidant capacity. However, 3 and 6 g RM / calf supplementation caused a significant (P<0.01) decline in lipids profile, kidney and liver functions, and Fe concentra