Electrocardiography (ECG) is a main diagnostic tool for diagnostics of rhythm disturbances. Since most pathological arrhythmias are only visible during movement and exercises the registration of exercising ECG becomes a mandatory diagnostic tool for monitoring of high-performance horses. Portable ECG monitor, developed together with specialists of National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” is an electrocardiograph with telemetric data transmission system and four electrodes providing six-lead real-time ECG  recordings at rest and during exercise. The objective of current study was validation of portable ECG monitor for diagnostics of arrhythmias in horses compared to a standard electrocardiograph. With this aim the ECG was performed by both devices simultaneously on animals with normal rhythm and rhythm disturbances. The ECG traces were therefore analyzed and compared. 14 horses of Ukrainian riding, Friesian, and Arabian breeds were divided in two groups: experimental one with arrhythmias, and control one with normal rhythm. ECG was performed by both devices simultaneously during rest, exercise, and post-exercise period. Electrocardiographic parameters were measured manually using on-screen calipers. Obtained data was analyzed using GraphPad Prism software by linear regression method for continuous parameters (HR, duration of QRS complex, PR, and QT intervals, and amplitude of P and S waves). For nominal parameters (rhythm, excitability, and conduction disorders) the analysis of sensitivity and specificity was performed. A total of 196 ECG records were analysed. Electrocardiographic intervals had high correlation: for HR and PR interval the correlation coefficient amounted to 0.98, for QRS complex and QT interval – to 0.97, for P and S waves – to 0.96. Among detected rhythm disturbances were physiological (second degree AV block first Mobitz type and SA block) and pathological arrhythmias (SVT and SVPCs). The sensitivity and specificity for rhythm, excitability, and conduction disorders of the portable ECG monitor compared to a standard electrocardiograph was 100 %. The portable ECG monitor allows to easily perform ECG registration during rest and exercises and to detect arrhythmias and other ECG abnormalities with accuracy, compared to a standard electrocardiograph.

Measurement of the main parameter of cardiac repolarization, namely QT interval, has a very high diagnostic value in human medicine, since its irregularities may indicate severe life-threatening ventricular tachyarrhythmias. The QT interval may vary not only with heart rate, age, sex, and autonomic tone, but also with horse breeds. Therefore, the description of its reference values for a specific breed is of great importance. The Ukrainian Riding Horse was bred as a show jumping, dressage and three-day eventing breed on the basis of Hanoverian, Thoroughbred and Trakehner stallions and local mares, as well as Hungarian Furioso, Gidran Arab and Nonius mares. Twenty-three horses of the Ukrainian riding breed were included in the study: 8 geldings, 8 mares, and 7 stallions aged 3-11 years. The electrodes for ECG recording were placed according to an adapted base-apex system. The ECG was registered during rest, exercise, and recovery periods. QT intervals were measured from resting to peak exercise levels on the traces of the 2nd lead and plotted against RR intervals. The piecewise regression model was fitted to the data plot. The values of Slope1, Slope2, and RRbend were compared to those of other breeds. The QT/RR relationship was relatively described by the piecewise linear regression model for all sexes (0.95 < r2 < 0.97). The sex of horses of the Ukrainian riding breed had a significant effect on the model. In terms of Slope1, Slope2, and RRbend values, Ukrainian riding horses are closest to Warmbloods, Standardbreds, and Thoroughbreds. The QT interval in horses should be corrected for breed and sex.

The indices of the content of proteins with molecular mass of 10-15 and 15-24 kDa in the plasmolemma of enterocytes of the small intestine of newborn calves in the dynamics from the birth till the age of 1 day were investigated. The study was performed on three groups of calves (the control group and two experimental ones) of Ukrainian black-and-white dairy breed by drawing the samples of enterocytes of jejunum and determining protein content of membrane lysate fraction by electrophoresis. The application of native liposomes based on soybean lecithin and "Membranostabil" medication for newborn calves with colostrum increases the expression of plasmolemic proteins of enterocytes with a molecular mass of 10-15 kDa. The dynamics of comparative analysis between fractions of protein expression with molecular mass of 10-15 and 15-24 kDa in the plasmolemma of the enterocytes of the jejunum of control and experimental groups of calves is shown. The result of application of native liposomes with phospholipid bilayer based on soybean lecithin and "Membranostabil" medication allows to assume the positive effect of these means on the level of colostral immunoglobulins in the serum of newborn calves.

The influence of medication “Membranostabil” on the indexes of content of proteins with MM of 33, 40, and 47 kDa in the plasmolemma of enterocytes of jejunum of new-born calves during the period from birth till the age of 24-hours was investigated. The research was conducted on calves (males) of Ukrainian black-and-white breed during the spring. Throughout the trial period, the calves of the control and experimental groups were kept on a standard diet for newborn calves, colostrum. In addition, calves of the experimental group got the medication “Membranostabil” based on the soybean lecithin. Proteins of plasmolemma of enterocytes of the jejunum of calves were isolated from the membrane fraction of lysates and examined by electrophoresis. Electrophoretic separation of proteins of plasmolemma of the jejunum enterocytes of newborn calves revealed proteins with MM of 37, 40 and 43 kDa on electrophoregram. The data of expression of immunoreceptor proteins with MM of 37, 40, 43 kDa and the dynamics of their changes depending on the time after birth in calves of the control and experimental groups were analyzed. The decrease in the total content of expression of proteins with MM of 37, 40, and 43 kDa in the membrane fraction of lysates of enterocytes of the jejunum of calves at the age of 6 hours compared to the newborn ones was demonstrated. The levels of expression of each immunoreceptor protein are considered with their comparative analysis between the individual fractions in the cytolemma of the enterocytes of the jejunum of newborn calves, which according to their molecular weights correspond to MM isoforms of FcγRIII/CD32. The data obtained showed a significantly higher expression of level of proteins with molecular mass of 37 kDa on the apical membrane of enterocytes, compared with proteins with MM of 40 and 43 kDa, both at birth of calves and at the age of 6 and 24 hours. Based on the data obtained, proteins with MM of 37, 40, and 43 kDa of plasmolemma of the jejunum enterocytes undergo significant changes in the process of postnatal ontogeny in cattle. These changes indicate the synthesis of these proteins in the enterocytes themselves in the process of formation of colostral immunity in newborn calves under the influence of the medication “Membranostabil” used by this research group, compared with calves of the control group. It is shown that the application of medication “Membranostabil” for the new-born calves activates the transport of immunoglobulins of colostrum in the intestine of these animals, assists the increasing of level of colostral immunity, and prevents the occurrence of digestive disorders. Findings of this research correlate with the results of clinical observation in newborn calves.

The results of application of preparation "Membranostabil" and phospholipid-bilayer macrocapsules on the base of soybean lecithin developed by us with the aim of correction of indexes of content of immunoglobulin M in the blood of newborn calves during formation of colostral immunity is shown. The indexes of content of immunoglobulin M in the serum of blood of the newborn calves in dynamic were investigated-from birth till the 11 th day of life. The research was conducted on the three of groups of calves (the control one and two research) of Ukrainian black and white milk breed with drawing of blood samples from the jugular vein. Immunoglobulins M were examined by gel electrophoresis in a thin layer of a polyacrylamide gel. Quantitative estimation of protein fractions was carried out by scanning of the electrophoregrams with subsequent reconstructing of them graphically and calculating by relative units or area using a computer program. The results have proved that the preparation "Membranostabil" and phospholipid-bilayer macrocapsules based on soybean lecithin activate transport of immunoglobulins in small intestine and promote veracious increasing of the content of immunoglobulin M compared to the control group. The content of immunoglobulin M in the serum of newborn calves in both of the research groups at the age of 6 hours credibly increased and was higher during the whole period of the research except for calves of the 1 st research group at the age of 7 days compared to the calves of the control group. The dynamic with comparative analysis of content of immunoglobulin M in the serum of blood between different groups of calves of control and research groups is shown.The increasing of the content of immunoglobulin M in blood of newborn calves prevents development of digestive disorders in these animals.