Studies On New Drug For Prevention And Treatment Of Parturient Hypocalcaemia In Dairy Cattle

Three experiments were designed to to preparation new drugs for prevention and treatment parturient hypocalcaemia of dairy cows.In experiment 1, two dairy farms were choosen to investigate dietary nutritional level and the incidence of subclinical hypocalcemia, hypomagnesaemia and related diseases in transition cows. The result show that hypocalcaemia and hypomagnesaemia are very common in transition period dairy cows, there was a regular pattern of the incidence of hypocalcaemia that rises gradually at prepartum, reaches highest at calving. Delivery and the formation of colostrums were direct pathogenic factors for hypocalcaemia, it can deteriorate by hypomagnesaemia.In experiment 2, compound calcium amino acid chelate oral solution were prepared.The results of the long-term stability, thermal stability, photostability and microbial limit tests suggest that the new drug accord with national standard in CP 2005. In experiment 3,Forty-five postpartum dairy cows were alternately assigned to three groups based on calving date. Cows in control group were fed conventional diet, calcium amino acid chelate solution was given to dairy cows in the second group base on conventional diet, calcium amino acid chelate with magnesium hypophosphate oral solution was given to the third group base on conventional diet. Blood samples were collected after calving. Plasma samples and milk samples were collected to analyze related parameters. Compared with the control, the second group increased plasma total calcium concentration, decreased plasma PTH concentration. Incidence of subclinical hypocalcemia and retained placenta in the second group were lower than control group, and the second group had higher milk protein than control group. Compared with the control, the third group increased plasma total calcium concentration, the concentration of plasma magnesium and the milk protein content than control group after calving. Incidence of subclinical hypocalcemia and retained placenta in the third group were lower than control group. The third group increased plasma CT concentration at 7 d postpartum very significantly than control group, and the incidence of hypomagnesaemia was very significant lower than control group.Hence, calcium amino acid chelate oral solution treatment was beneficial in improving the health status and milk quality in postpartum dairy cows, especially the oral solution which was added magnesium hypophosphate.