Comparison And Evaluation Of Blood Metabolic Profiles In Peripartum Healthy, Ketotic And Subclinically Hypocalcemic Dairy Cows

The periparturient period (also called the transition period) of4weeks before and4weeksafter calving from the pregnant, nonlactating state to the nonpregnant, lactating state is often adisastrous experience for the cow. High producing dairy cows struggle to meet energy demandsand handle various transitional changes during late gestation and early lactation. Once the bodycan not respond correspondingly because of physiological and pathological factors, which willcause production diseases such as ketosis, fatty liver and hypocalcemia and so on. With theincreasing of intensive degree of modern dairy cattle farming industry, production diseases of thetransition cow were characterized by herd epidemic, resulting in decreasing milk yield andincreasing the susceptibility to other disease, which has a tremendous impact on dairy cowindustry. Therefore, it is necessary to carry out the herd monitoring of nutritional and metabolicstatus. Different physiological stages experience different nutritional and metabolic status ofperiparturient dairy cows, and monitoring blood biochemical indexes of metabolic profiles mayevaluate nutritional and metabolic status of this period, and forecast and warn production diseasesof the transition cow. Therefore, using “campton metabolic profiles” by detecting termly somecomponents in blood, urine and milk could evaluate nutritional and metabolic status of individualand group, and warn an occurrence of metabolic diseases.Blood profiles and changes in body condition (BCS) have been used to monitor metabolicdisturbances around parturition and, in early lactation, to investigate problem herds as well as topredict the risk of diseases such as ketosis and subclinical hypocalcemia. Parameters used tomonitor imbalances in energy metabolism included glucose (GLU), non-esterified fatty acids(NEFA), betahydroxybutyrate (BHBA) in blood and BCS. This key indicator for each of theseparameters, when they are used to monitor herd health, is the proportion of cows outside apre-defined range. Although other blood biochemical indicators have not be used for routinemonitoring system, which does not mean that they are trivial indexes, only due to lacking of theexact defined range. To monitor glucose, lipid, protein, mineral element metabolism, insulinsensitivity and inflammatory in blood of healthy periparturient dairy cows, we need do the firstthing that it is definiting a range and rule of fluctuation of blood biochemical indexes in healthyperiparturient dairy cows, which can provide theoretical and experimental basis for utilizingmetabolic monitoring to evaluate nutritional and metabolic status, forecast and warn productivediseases in periparturient dairy cows. The change of blood metabolic parameters in periparturient dairy cows: The resultsshowed that essentially all dairy cattle experience a period of negative energy and calcium balance,decreasing insulin sensitivity, and affected normal function of liver during the periparturientperiod. We also definited the range and rule of fluctuation of energy and mineral elementmetabolism, hormone, cytokines, and acutephasicprotein in dairy cows during late pregnancy,parturition and early lactating. The indicators include NEFA, BHBA, RQUICKI, TG, TBIL, DBIL,IBIL, AST, GGT, LP, ⅠC TP, IL-6, IL-8, HP, SAA, HYP,1,25(OH)2D3, PTH, Ca, Mg, K and Zn.Periparturient dairy cows, especially near parturition, the levels of cytokines (IL-1, IL-6and IL-8)and Zn concentration decrease, the levels of acutephasicprotein (HP and SAA) were high, whichmay be related to low immunity of dairy cows in this period.On the basis of definiting the range and rule of fluctuation of blood metabolic profiles inperiparturient dairy cows, we measured and compared the difference of glucose, lipid, and proteinmetabolism-related analytes in healthy, ketotic and subclinically hypocalcemic cows of transitionperiod using the viewpoint and theory of preventive medicine by clinical examination,biochemical methods and ELISA. We also carried out the correlation analysis and screened someindexes that are of diagnostic value. In addition, the usefulness of relative indicators in diagnosingketotic and subclinical hypocalcemic is compared by receiver operating characteristic curve (ROCcurve), and the cut-point was determined, which provide the efficient data support for thediagnosis and herd monitoring of ketosis and subclinical hypocalcemia in dairy cows during theperiparturient period.The evaluation of blood metabolic parameters in ketotic dairy cows: The results showedthat ketosis is still quite common to occur at1-3weeks postpartum, especially at1weekpostpartum. Therefore, testing programs with the objective of monitoring the prevalence of ketosisshould focus on the first3weeks postpartum. Ketotic cows are characterized by reduced insulinsensitivity, abnormal liver function index and immunosuppression. The concentrations of NEFA,BHBA and GLU in blood are the major indexes for monitoring energy metabolism state of ketoticdairy cows. We initially confirmed some sensitive indexes for diagnosing ketosis and herdmonitoring, such as RQUICKI, AST, AST/ALT, LDH, DBIL, TBIL and CREA, and theircut-point.In addition, during the screening process of periparturient and ketotic dairy cows, we foundtwo quite different types of ketosis can occur, the hypoglycaemic-hypoinsulinaemic andhyperglycaemic-hyperinsulinaemic type. According to this, we compared Type I (the former) withII (the latter) ketosis. The results indicated that compared with Type I ketotic dairy cows, Type IIketotic dairy cows have a marked change of liver function and tissues, and insulin resistance. Theoccurrence of Type II ketosis in dairy cows was closely related to fatty liver.The analysis of blood metabolic parameters in subclinical hypocalcemic dairy cows: Theresults showed that compared with the healthy dairy cows, subclinical hypocalcemic dairy cowshave more serious negative energy balance, which may be the key reason of subclinical hypocalcemic dairy cows susceptible to energy metabolism diseases, such as ketosis and fatty liver.Some serum enzyme parameters (AST/ALT and GGT), pro-inflammatory factor andacutephasicprotein (HP and SSA) showed a significant rise, which indicated that the course ofsubclinical hypocalcemia in dairy cows exist inflammation and hepatocyte injury. Highconcentration of P and low concentration of Mg in blood are both risk factors for causing and/oraggravating negative calcium balance. Compared with the healthy cows, subclinical hypocalcemiccows displayed a blunted PTH response to, at least in part, the decline of blood Ca levels, resultingfrom inhibition of the synthesis of1,25(OH)2D3, and suppression Ca absorption from intestine,reabsorption from kidneys, and resorption from bone. The decreasing of Zn concentration inserum may have association with immunosuppression in subclinically hypocalcemic cows. TRAPand GGT are the sensitive indexes for evaluating metabolism condition of subclinicallyhypocalcemic dairy cows, and also we have definited cut-point.In conclusion, periparturient dairy cows experience a series of physiological perturbance, andthe metabolic process of glucose, lipid, protein and mineral elements have interactional relations.Many factors can influence metabolic condition of individual and group. It is unreasonable toadopt single monitoring index. The combination of some parameters are reliable for diagnosingand monitoring production diseases of the transition cow.