The Dynamic Changes Of Blood Physiological And Biochemical Indexes In Transition Cows

Perinatal stage in cows starts from prenatal three weeks to postpartum three weeks. The major infectious diseases and metabolic diseases occur during this period. Perinatal cows would go through a series of physiological changes of pregnancy, birth and lactation. In particular, the energy demand of high producing dairy cows increased in the later period of pregnancy and the early stage of lactation, but the intake of dry matter decrease. While the energy needed to power lactation after childbirth was much more than that provided by dry matter intake. This would cause negative energy balance (NEB). Finally, fat mobilization is the inevitable result of energy negative balance of perinatal cows. Excessive fat mobilization in perinatal cows is also the reason why the immunity reduces and infectious diseases occur. Fat mobilization significantly increased morbidity of the cow metabolic diseases (such as ketosis and fatty liver) and infectious diseases (such as mastitis and hysteritis). In this study, the dynamic changes of the blood physiological and biochemical indexes revealed physiological and biochemical characteristics of perinatal cows, which provide theoretical basis for prevention and control cows perinatal diseases effectively.1. The changes of hematology indexes in transition cowsIn order to study the physiological characteristics of perinatal cows,40prenatal40d cows have been chosen, their whole blood was collected from the tail vein every5d to do a detection of hematology indexes. The results showed that the WBC in prenatal5d and on the day of birth (0d) increased significantly (P<0.05or P<0.01), then it returned to normal level basically in postpartum5d. The result of NEU and LYM were in line with the variation trend of WBC. The RBC, HB and HCT were moderately elevated (P<0.05) on the day of birth. PLT began to rise in prenatal5d, the postpartum level were higher than the prenatal one (P<0.05). All indexes above are within the normal range. Results indicated that all physiological characteristics in perinatal cow were the changes of the hematological parameters of white blood cells, red blood cells and platelets.2. The changes of serum lipid peroxidation indexes in transition cows40prenatal40d cows have been chosen, their whole blood was collected from the tail vein every5d to do a detection of serum lipid peroxidation indexes. The results showed that GSH-Px and SOD activity of serum were decreased gradually in the prenatal, while the activity of CAT was evaluated in the prenatal. But all these were decreased in post partum (P<0.05or P<0.01). The content of MDA in serum was evaluated in the prenatal, and then it started to decrease gradually in post partum. In conclusion, perinatal cows showed the change of hematological parameters and physiological characteristics of oxidation state of imbalance.3. The changes of serum glucose and insulin levels in transition cowsIn order to study the situation of glycometabolism in perinatal cows,40prenatal40d cows have been chosen, their whole blood was collected from the tail vein every5d to do a detection of the concentration of serum Glucose and insulin. The results showed that serum insulin levels of cows reduced gradually from prenatal15d, and reach to the lowest level on postpartum5d (3.40+/-1.23μIU/mL), then gradually rise until it went back to a steady state on postpartum25d. The level of Serum glucose fell sharply in prenatal10d, on the day of the delivery, it went to the bottom (1.57mmol/L), and it showed an ascendant trend in postpartum. These results indicated that there was an obvious low sugar symptom in perinatal cow. Serum insulin was bound up with the glucose levels.4. The changes of serum fat metabolism indicators in transition cowsIn order to study the situation of glycometabolism in perinatal cows,40prenatal40d cows have been chosen, their whole blood was collected from the tail vein every5d to do a detection of the concentration of serum Triglyceride (TG), Total cholesterol (CHOL), non-esterified fatty acid (NEFA), β-hydroxybutyrate (β-OHB), Leptin, neuropeptide Y (NPY). The results showed that serum NEFA content began to rise gradually from prenatal30d, reached to peak on the day of birth (733.4+200.4μmol/L), and thereafter decreased sharply. Serum β-OHB levels began to rise in prenatal35d, reached to top (39.98+11.33μmol/L) on10d prenatal, began to decline from prenatal5d, and minimize (20.58+4.87μmol/L) on the calving day, there were significant differences among different time periods (P<0.05). The content of serum TG fell slowly after prenatal20d, and kept in the lower levels during the postpartum period. The content of serum CHOL began declining gradually in prenatal35d, that of calving day is the lowest (1.81+/-0.39tendency/L), thereafter rising gradually. The content of leptin significantly increased after the prenatal35d (P<0.05), and showed a trend of gradual decline from prenatal10d to postpartum stage. Serum NPY levels began to rise from prenatal45d, reached to peak (3068+/-595.1ng/L) on prenatal15d, then declined until postpartum10d (1951+/-408.1ng/L), thereafter showed a trend of rise, there were significant differences among different time periods (P<0.05). The content of serum NEFA was negatively correlated with that of CHOL (P<0.01). The content of β-OHB had a very significant positive correlation with that of serum TG and leptin (P<0.01). The content of serum TG was significantly correlated to that of leptin. These results indicated that obvious fat mobilization occurred during the perinatal stage of cow. The content of serum NEFA and beta OHB can be used as a reliable indicator of fat mobilization state in the perinatal period.5. The changes of Serum trace elements in transition cowsIn order to study the situation of glycometabolism in perinatal cows,40prenatal40d cows have been chosen, their whole blood was collected from the tail vein every5d to do a detection of the concentration of serum trace elements, including Se, Fe, Zn, Cu, Mn etc.. The results showed that the content of Serum Cu significantly elevated on calving day (0d) and postpartum10d (P<0.05). The content of serum Se started a trend of increase in prenatal10d, the content of calving day and postnatal10d was significantly different from that of the antenatal stage (P<0.05). The content of serum Fe Significantly reduce on the calving day, it has a significant or extremely significant difference compared with prenatal (P<0.05or P<0.05). The content of serum zinc showed a trend of decrease in the antenatal, minimized on the calving day, and then raised gradually; there were significant differences among different time periods (P<0.05). These results indicated that there were changes of the dynamic balance of serum trace elements in perinatal cows.