Apparently, healthy 105 cows were used in this study to investigate the effect of age, pregnancy and lactation on osmotic fragility of Holstein Friesian cow's erythrocyte and its membrane phospholipids. These healthy cows were classified according to age and their physiological status (pregnancy and lactation) into 7 groups. Blood samples were collected from different groups for determination of osmotic fragility by osmotic fragility test and phospholipids fractions by thin layer chromatography. The present study revealed that the fragility was increased with advanced age. Moreover, the pregnant cows showed a significant decrease in the fragility of erythrocytes as compared with the lactating ones. Regarding to phospholipids, the results showed that increasing age caused a significant decrease in total phospholipids. While, age, pregnancy and lactation caused non-significant changes in sphingomyelin and phosphatidylserine percentages. Concerning the phosphatidylcholine and phosphatidyl-ethanolamine, the results revealed that increasing age caused significant decrease in phosphatidylcholine and a significant increase in phosphatidylethanolamine percentages. Regarding the pregnancy and lactation, pregnant cows had significantly higher percentages of phosphatidylcholine than lactating cows of the same age. From this study, it is concluded that maintenance percentages of phospholipids fractions of erythrocyte membrane is essential for retaining the normal lifespan of the cell. Whenever distortion in percentages of phospholipids occurs, the cells undergo lysis. Thus, it is recommended that old and lactating cows should be supplemented by antioxidant to increase the resistance of erythrocytes to improve the productivity and health care during these critical physiological periods
(PDF) EFFECT OF AGE, PREGNANCY AND LACTATION ON ERYTHROCYTE OSMOTIC FRAGILITY AND MEMBRANE PHOSPHOLIPIDS OF HOLSTEIN FRIESIAN COWS.