Association Of Ketosis With Energy Metabolism,Productive And Reproductive Performance In Dairy Cows Pre-and Postpartum

The purpose of this study was to find out the association of bovine ketosis with energy metabolism、productive and reproductive performance, to provide theoretical basis for the prevention and cure of bovine ketosis、and hepatic dysfunction diseases, and to improve the healthy level of dairy cows. In this study,31holstein cows were selected with the similar age、pregnancies and body condition. The samples were divided into two groups basing on the plasma content of ketone bodies, higher ketone body group (HK, KET>6mg/dl, n=14) and normal ketone body group (NK, KET<6mg/dl, n=17). Each parameter of energy metabolite and liver function were measured in two groups from one week before delivery (-1)、delivery day (0) and1、2、3、4、5、6、7、8weeks after postpartum respectively. Milk yield (MY)、body weight (BW)、body conditions (BCS) and calculating the increasing speeds of milk yield (IMYR) were also recorded respectively. The data of reproductive traits (empty pregnant period, estrus ratio, the first time of AI postpartum, AI intervals, insemination index, conception rate in estrus, average intervals of calving, etc.) were recorded at the same time for the two groups. The results showed that, KET content of14cattle were over6mg/dl, the percent of ketosis was45%in31samples. Ketosis had occurred for the first week postpartum; at the second week postpartum, the activity of AST in cattle of ketosis were significant higher than that of normal cattle (P<0.05), then the clinical manifestation and histopathological characteristic of hepatic dysfunction were emerged. The other blood biochemical indexes also provided obvious difference with varying degrees and had correlations to ketosis. Milk yield was lower in ketosis than that of normal cattle at2-4weeks after postpartum, and it was significant difference at the third week (P<0.05), BW and BCS were dropped dramatically after postpartum. The reproductive performance of cows with ketosis was inferior to normal cattle, and the total reproductive performance was well below the lowest level of national. The test results had shown that the milk yield at early milk stage was increasing quickly, thus lead to negative energy balance, which could triggered the development of ketosis; once the ketosis occured, the hepatic dysfunction would took place subsequently, that would bring out obstacle of body energy metabolism and would reduce the productive and reproductive performance of dairy cattle.