Evaluation of Cinical and Clinical Chemical Parameters in Periparturient Cows

摘要

Certain blood parameters and clinical symptoms have been connected with milk fever and a hypocalce- mic condition in the cow. The present study intended to establish a mutual connection between relevant blood parameters and potentially valuable background infor- mation about the cow and its observed clinical symp- toms at calving. Two veterinarians were summoned within 12 h of parturition of 201 cows, distributed among 41 Danish commercial herds. Cows were at dif ferent parity levels (2 to 10) and breeds and manage- ment differed broadly among herds. A blood sample was taken from the vena jugularis or the tail vein and was subsequently analyzed in the laboratory. Furthermore, 13 different clinical symptoms were recorded as cate- gorical data. We investigated associations among the data obtained. We assessed an interpretative model for actual blood calcium level with blood parameters and background knowledge of the animals. We established a path analysis using background knowledge, blood pa- rameters, and results of clinical examinations to un- cover causal connections among the variables. Twenty-six percent of the animals were diagnosed as having milk fever and subsequent blood analyses revealed a high frequency of hypocalcemia within the general range from 0.69 to 2.73 mmol of Ca per liter. Rectal temperature, inorganic blood phosphate, and potassium were all directly correlated with blood cal- cium, while glucose, lactate, and magnesium were in- versely associated with calcium. Blood osteocalcin was significantly lower in hypocalcemic animals, indicating that de novo synthesis of bone was arrested during hrpocalcemia. A mixed effect linear interpretative model explained 75/100 of the variation in blood calcium. Clinical symptoms like mood, appetite, muscle shiv- ering, rumen motility, and paresis were individually correlated with blood calcium and were thereby pre- dictive of hypocalcemia. The path analysis showed the central role of calcium in affecting the clinical symp- toms. However, several other factors contributed to hy- pocalcemia.