Study On The Clinical Pathology Of Left Displaced Abomasum In Dairy Cows

Left displacement of abomasum (LDA) means that the abomasum shifts to a left of the rumen from the abdominal floor. With intensive dairy farm and high milk yield, the incidence of LDA in dairy cows increases gradually in recent years. The purpose of this study is to investigate the clinical pathology of LDA in dairy cows, and provide the prevention of LDA. In this experiment,10 dairy cows were spontaneous LDA, five were healthy control and 3 were artificial LDA dairy cows. There were 23 parameters in blood, rumen fluid and abomasal fluid of experimental dairy cows were tested, then, the pathology of abomasum in the 3 artificial LDA dairy cows observed after the experiment.Eexperiment one, blood were collected from 10 dairy cows with clinical LDA and 5 control cows. Rumen fluid and abomasal fluid were collected from spontaneous LDA cows by surgical operation and from artificial LDA cows and control cows by rumen and abomasum puncture. The parameters of potassium, sodium, chlorine, calcium, pH, GLU and NEFA in blood, acetic, propionic, butyric, lactic, potassium, sodium, chlorine and pH in rumen fluid, acetic, propionic, butyric, potassium, sodium, chlorine, magnesium and pH in abomasal fluid were tested.The results showed that in spontaneous LDA cows, as compared with control cows, potassium, sodium and chlorine in blood plasma decreased and plasma calcium increased, GLU in blood plasma decreased significantly (P<0.01) and NEFA in blood plasma increased significantly (P<0.01); Sodium and chlorine decreased, potassium increased in rumen fluid, acetic, propionic, butyric and VFA decreased in rumen fluid; Potassium and magnesium increased, sodium and chlorine decreased in abomasal fluid, acetic, propionic, butyric and VFA increased in abomasal fluid.Experiment two, three LDA cows were artificial by surgical operation, which were installed by permanent rumen cannula and abomasal cannula. Blood, rumen fluid and abomasal fluid were collected before the surgery and at day 3, 5, 7, 9, 11, 13, and 15 after surgery. The tested indexs were the same as experiment one. Meanwhile, the pathology of abomasum in the artificial LDA dairy cows observed after the experiment. The results indicated that exception that potassium, sodium and calcium in blood was normal, chlorine increased, potassium decreased in rumen fluid, sodium and lactic acid in rumen fluid increased significantly(P<0.01), others parameters in blood, rumen fluid and abomasal fluid had the same changes as experiment one. Pathology of artificial LDA cows is diffuse hyperemia, interspersed hemorrhage spot and anabrosis in gross anotomy, and is hemorrhage, degeneration and necrosis under the microscope in abomasal mucosa.Conclusion obtained that there were the negative energy balance with LDA dairy cows. The major risk period was the four weeks after calving. There were VFA decreased in rumen fluid and it increased in abomasal fluid of LDA dairy cows. Interspersed hemorrhage spot and anabrosis in gross anatomy with abomasums.