Novices using a Veterinary Ultrasound machine to measure the ovaries of horses can locate the ovaries through the horse's bladder. The echo images of mare urine vary greatly, and in the case of extremely viscous urine, the ultrasound images of veterinary Ultrasound Machines differ from no echo to strong echo. After seeing the bladder, the ultrasound probe is pushed towards the head until the uterus appears on the screen. The probe is placed on the dorsal side of the uterus at the bifurcation level; Starting from here, the probe rotates laterally along the uterine angle until it sees the ovary, and then returns to the opposite side to see another ovary. In this method, the uterine horn is scanned layer by layer, with each slice representing a cross-section through the uterine horn. The uterine body and cervix are usually observed in a longitudinal section.

High definition B-ultrasound pregnancy analyzer for detecting horse follicles

Animal B-ultrasound machine for detecting horse follicles:

Hair follicles exhibit a fluid filled structure (anechoic or black) in ultrasound images. The silencing characteristics of follicles are caused by the lack of reflection of sound waves when passing through relatively cell-free and transparent follicular fluid. The shape of follicles varies from circular, elliptical, irregular polygonal to nearly angular. These shape changes are the result of pressure differences between adjacent follicles, corpora lutea, and even the ovarian stroma itself. The follicular wall is highly echogenic and thin. Bright images (enhanced artifacts) can be seen behind larger fluid filled vesicles. It is relatively easy to detect 3mm follicles using ultrasound with a frequency of 5.0 MHz.

Ultrasound image of follicles during horse estrus (circular) with a diameter of 40 millimeters

Detection of round follicles with a diameter of 40 millimeters during the estrus period in horses using a veterinary B-ultrasound machine

About 192 hours before ovulation, the diameter of the dominant estrus follicle in horses is about 25 millimeters. Then they grow at a rate of 2 to 2.5 millimeters per day and reach a diameter of 41 to 45 millimeters 24 to 48 hours before ovulation. There is no further growth for 1 to 2 days after ovulation. The dominant follicles are round for 3 days or more before ovulation, and in the days before ovulation, the estrus follicles will become more elliptical or irregular in shape. The ultrasound shape and size of follicles can be used to help predict the time of imminent ovulation. If the large follicles are irregularly shaped, at least 40 millimeters in size, and may have stopped growing for some time, ovulation should be expected to occur soon. When the recently present follicles cannot be found in subsequent examinations, ovulation can be identified through ultrasound. The ovulation process takes a few seconds to a few minutes. The hair follicle wall seems to fold inward; The follicular cavity has an irregular shape and sometimes contains a small amount of residual fluid.

Follicles with a diameter of 45 millimeters before ovulation (irregular)

Follicles with a diameter of 45 millimeters before ovulation (irregular)

After ovulation, the disappearance of preovulatory follicles can be determined by rectal palpation. However, sometimes the symptoms of estrus may alleviate, while pre ovulatory follicles seem to persist. It is difficult to distinguish between persistent follicles and hard bleeding bodies solely through rectal examination. The hemorrhagic body can be identified by its uniform gray echo structure. On the other hand, the content of persistent follicles is clear. When luteinization occurs, wall thickening is distinguishable.

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