Purpose: Conduct an analysis of cardiac rhythm variability in the cows of the Jersey breed with a different vegetative status.Materials and methods. Indicators of the electrocardiogram (ECG) and cardiac rhythm variability studied on cows of the Jersey breed (n = 103). For the analysis and removal of ECG, the animal studied used the program «Conan-4.5» in the system of frontal administrations according to the method of P. M. Roshchensky. Clinical research methods were carried out according to the methods of clinical inspection of animals B. V. Ears and included — inspection, palpation, percussion and auscultation of the heart area.Results. Among the entire studied array of animals, the largest amount was sympathyone — 50,5%, normotonics — 24,3%, hypersympathicotonics — 16,5%. The smallest amount — vagotonic — 8,7%. For the vagotonic, the respiratory modulation index was 8,16±0,02%, the index of the sympathetic system is 43±0,1%, and the index of slowly wave arrhythmia is 0,8±0,1%. This group of cows parasympathetic (software) prevails over the sympathetic department of the vegetative nervous system. For normotonics, the value of the respiratory modulation index was 4,14±0,03%, the index of the sympathetic system is 96±0,2%, and im is 2,5±0,2%. This group is characterized by an equilibrium state between sympathetic department and VNS. The ids for sympathicotonists amounted to 2,78±0,03%, the index of the sympathetic system is 195±0,2%, and im is 8,2±0,1%. At sympathicotonists, which are characterized by a predominance with VNS above software. The hyper smpathetical respiratory modulation index was 1,34±0,02%, ICAS — 588±0,1%, and im is 11,4±0,3%. In hypersympathicotonists, which are characterized by the predominance of the super-viper vehicle of the vegetative nervous system over parasympathetic.Conclusion. The separation of the entire array on the subgroups based on the vegetative status of animals was based on the indicators of the voltage index of regulatory systems. To confirm the correctness of the separation of the studied array of animals on the subgroup, statistical processing was carried out and a classification matrix was built. Also, to confirm the classification separation matrix, additional statistical processing of the material of the differences between the obtained groups in the square of the distance of the Mahalonobis D2 was carried out. In the course of further registration and mathematical analysis of the variability of the heart rate of cattle (cows of the Jersey breed) with the help of a modern complex electrophysiological laboratory «Conan-4.5» features of indexes of A. Ya. Kaplan were established.