А. А. Олешкевич The authors prove a possibility of laboratory diagnostics of early stages of pregnancy in female horses. Exposure of a temperature-controlled mare blood samples to standing amplitude-modulated ultrasonic wave with a generation frequency of 0.88 MHz, an intensity of 0.05 W/cm 2 and a modulation frequency from 10 to 20 Hz for 15-20 sec leads to a significant change in the morphological state of blood cells. The use of simple and accessible methods of light microscopy has revealed the aggregation of leukocytes with the simultaneous absence of any signs of lysis and cellular destruction of erythrocytes in the blood of pregnant mares. The developed technique can be used for non-invasive ultrasonic examination of the blood of female farm animals in the early stages of pregnancy. Due to its simplicity and low cost, the technique can be implemented both as an independent diagnostic method, and as a supplement to the conventional veterinary clinical methods.
Научная статья 
blood morphology