Influence of pregnancy on diurnal and seasonal changes in glucose level and activity of FDPA, AlAT and AspAT in mares

Circulating endocrine, metabolic, and haematologic indices during the peripartum period of Darehshori mares

The characteristics associated with equine peripartum period are different from those of other periods. Information concerning the values and dynamic changes of circulating peripartum endocrine, metabolic, and haematologic indices may improve the understanding of the whole body haemostatic patterns which lead to parturition, lactogenesis, and estrus in the horse. The present study aimed to evaluate these changes around parturition in Darehshori breed. For this purpose, blood sampling was performed on six clinically healthy Darehshori mares (10 years old) about one week prior to parturition, three days following parturition, at the beginning of estrus, and one week after estrus. Circula­ting values ​​of glucose, estrogen, progesterone, cortisol, T3, T4, TG, cholesterol, HDL, LDL, VLDL, RBC, HGB, HCT, MCV, MCH, MCHC, WBC, neutrophil, lymphocyte, and PLT were assessed in all samples. Progesterone concentrations were minimum before parturition and increased significantly one week after foaling heat (P=0.035). Cortisol level was significantly higher during foaling heat compared with other periods (P=0.029). T4 levels significantly increased from pre- to post-partum periods (P=0.001), but T3 showed increased and decreased values during the study period. All serum lipid profile parameters were significantly reduced from pre to postpartum period (P<0.05). Haematological parameters in mares significantly changed during the peripartum period (P<0.05). Based on the results, the metabolic, haematological, endocrinological, and stress indices in Darehshori mares were found to change around parturition and the first estrus. These changes were largely dependent on hormonal mechanisms related to pregnancy and parturition occurring in normal mares.

Changes of biochemical environment and body weight in healthy periparturient Lipizzan mares

The aims of this study were to determine the concentrations of calcium, magnesium, phosphorus, chlorine, potassium, sodium, urea, total cholesterol, triacylglycerols, non-esterified fatty acids, total protein, creatinine, total bilirubin, aspartate aminotransferase, insulin, insulin growth factor 1, and glucose in the blood serum and to monitor the body weight changes in nine clinically healthy Lipizzan mares at weekly intervals within 2 weeks before and 2 weeks after the parturition. A significant body weight loss (P < 0.01) was found in the mares after the foaling. The peak of insulin growth factor 1 concentration in serum was reached at the day of parturition and similar patterns were revealed for the concentrations of insulin and glucose. After parturition, all these indices were significantly decreased. The concentrations of phosphorus and triacylglycerols were decreased, while the concentrations of potassium and sodium were increased at the day of parturition. Moreover, the concentration of non-esterified fatty acids was increased at the day of parturition (P < 0.05) with a tendency to higher values even on the 7th day postpartum. Other studied indexes remained relatively stable throughout the transition period. We can conclude that periparturient mares face some degree of negative energy balance with concomitant significant homeostatic and homeorhetic changes. For this reason, our results can be used as a basis for reference values and a diagnostic tool to examine the health status in horses during the transition period.

Immunoreactive insulin-like growth factor I and insulin in blood plasma and milk of mares and in blood plasma of foals

Concentration of (total) globulin was relatively stable in blood plasma of mares, but rapidly decreased in colostrum to very low levels within 2 days after parturition. In foals, after intake of the first colostrum, globulin increased within 1 day in blood plasma, but remained at lower concentrations than those measured in mare plasma. Concentrations of immunoreactive insulin (iI) were high during the first 2 months of lactation in blood plasma of mares and then decreased, were high in first colostrum and then decreased drastically, and remained at low concentrations up to weaning in blood of foals. In mares, concentration of immunoreactive insulin-like growth factor I (iIGF-I) in plasma increased during late pregnancy, peaked 2 days after parturition, and then gradually declined until weaning. iIGF-I was highest in first colostrum and then dramatically decreased within the first 2 days of lactation. In foals, iIGF-I gradually increased over the first 2 months of life. IGF-I in the horse appears to be bound to proteins of similar molecular weight as in cattle. The study demonstrates different patterns of changes in plasma iIGF-I and iI concentrations in mares and their foals, whereas iI, iIGF-I and globulin changes in colostrum and milk occurred in parallel. Furthermore, plasma iI and iIGF-I behaved differently, while colostrum iI and iIGF-I behaved similarly, in mares compared with dairy cows.