Oxidative stress in cows according to calving season: passive calf immunity and its relationship with colostrum quality.

This study details the relationship between maternal plasma oxidant-antioxidant enzymes with colostrum quality, serum gamma glutamyl transferase (GGT), immunoglobulin G (IgG) and IgM concentrations of calves in the different calving seasons. Holstein breed cows between two and eight lactations and their calves were enrolled in the study. Holstein cows calving in winter (n=45) and their calves (n=45) were assigned to the winter group, while cows calving in summer (n=45) and their calves (n=45) were assigned to the summer group. Samples for malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were collected on day -21±3 before expected calving and also on calving day (Day 0). IgG and the specific gravity of the colostrum were determined after calving. Serum GGT and IgG and IgM were measured before the feeding, with colostrum, of calves (0 hours) and also in the 24th hour following the feeding of colostrum. Plasma MDA levels at -21±3 and 0 days in the summer cows were determined to be higher. GSH-Px activity was higher in the winter cows. IgG levels and the specific gravity of the colos- trum were also higher in the winter cows. Calf IgG levels at the 24th hour of life were higher in the winter cows. In the winter group, IgM levels at 0 and 24 hours were also higher. While MDA was negatively correlated with IgG, IgM, GGT, IgG and the specific gravity of colostrum, GSH-Px activity had a positive correlation with IgG, IgM, GGT, IgG and the specific gravity of colostrum. The observed differences in plasma MDA, GSH-Px, calf serum IgG and IgM levels, and colostrum quality between both groups suggest a possible seasonal effect. The relationship between maternal oxidant-antioxidant enzymes, colostrum quality, and passive calf immunity revealed that these enzymes could be used as indicators in the evaluation of calf health and colos- trum quality.

Effects of prostacyclin on spinal cord ischemia: an experimental study.

BACKGROUND: Paraplegia after thoracic aortic aneurysm has an incidence of 2.2% to 24%. This study was planned to show the beneficial effects of prostacyclin on spinal cord ischemia. METHODS: Twelve rabbits underwent 30 minutes of aortic occlusion. Six rabbits received prostacyclin, whereas the remaining rabbits did not. Prostacyclin administration was started with a rate of 5 ng/kg/min 5 minutes before aortic occlusion. This dosage was increased to 25 ng/kg/min during aortic occlusion. Prostacyclin administration after aortic occlusion was maintained for a period of 5 minutes. During this period, prostacyclin dosage was 5 ng/kg/min. RESULTS: One rabbit in the prostacyclin group and five rabbits in the control group were paraplegic. Arterial pressure proximal to the clamp was 65 +/- 7 mm Hg before aortic occlusion and 78 +/- 10 mm Hg during aortic occlusion in the control group and 68 +/- 12 mm Hg before aortic occlusion and 65 +/- 6 mm Hg during aortic occlusion in the prostacyclin group. Arterial pressure distal to the clamp was 11 +/- 4 mm Hg during aortic occlusion in the control group and 18 +/- 5 mm Hg during aortic occlusion in the prostacyclin group (p = 0.02). CONCLUSIONS: Intravenous prostacyclin reduced the neurologic injury caused by spinal cord ischemia and reperfusion after 30 minutes of aortic occlusion in the rabbit model.