Five important applications of pig B-ultrasound in sow reproduction

(I) Early pregnancy monitoring of sows Using B-ultrasound for early pregnancy monitoring in pig production is a simple and effective method that can reduce costs and bring higher economic benefits. B-ultrasound is used for sow pregnancy monitoring and is considered to be a good method for rapid and highly accurate monitoring of sow pregnancy. During monitoring, the sow can stand or lie on its side without additional restraint. The detection site is on the sow's posterior ribs and on both sides of the last pair of nipples. Coupling agent is applied locally. No need to cut hair. The probe is aimed at the pelvic entrance and scanned in the direction of the uterus. When the typical dark area of the gestational sac is seen, early pregnancy is confirmed to be positive. Skilled operation can complete the monitoring of a pig in a few seconds.

(I) Ovulation monitoring Pig B-ultrasound monitors the development and ovulation of follicles to provide a scientific basis for determining the breeding time and improving the breeding rate. For modern intensive pig farms, centralized breeding and farrowing can be carried out according to ovulation monitoring. For sows whose follicles have not yet matured according to B-ultrasound observation, estrus treatment can be carried out to synchronize estrus, and try to synchronize breeding in the same cycle, so as to improve productivity and economic benefits.

(III) Predicting gestational age and number of fetuses, monitoring fetal development By measuring various indicators of the fetus, the gestational age of the fetus is determined, and the date of production is predicted: using pig B-ultrasound to predict the number of fetuses, this is a deeper application of pig B-ultrasound, which requires certain operating experience. Using B-ultrasound to regularly track and monitor pregnant sows can not only monitor the development of the fetus, but also timely detect abnormal conditions such as stillbirth, as well as the situation of postpartum uterine involution.

(IV) Determination of Backfat thickness and Eye muscle area of live breeding pigs backfat thickness and eye muscle area of pigs are directly related to lean meat rate. As two important indicator parameters in pig genetic breeding and performance identification, they are highly valued, and their accurate determination is of great significance. The use of B-ultrasound to measure pig back fat thickness and eye muscle area can accurately select the measurement site, which makes the measurement results reliable and accurate. Pig B-ultrasound can accurately measure the back fat thickness and calculate the eye muscle area of live pigs without damaging the reproductive performance of the body. It greatly improves the scientificity and accuracy of breeding and selection.

1. Pig restraint. Measurement in the pig house, especially when measuring in the confinement fence, no special restraint is required: the pigs stand naturally or are fed with fine feed to keep quiet. If the operation is carried out in the field, the iron fence can be used to limit the position or the pig can be restrained with a pig traction device to make it stand naturally.

2. Measurement position. Fat thickness and eye muscle area can be measured at the same position or on the same ultrasound section. At present, most units in my country take three points for measurement. That is, the back edge of the scapula, the rear ribs and the waist and sacrum junction 4cm away from the midline of the back as the measurement points for fat thickness and eye muscle thickness. Then take the average of the three points. These three points can also be used as the measurement position of the eye muscle area. Some people only measure 4cm from the midline of the back between the 10th and 11th ribs.

3 Operation procedures The pigs to be measured are naturally restrained in the restraint pen. The measurement position should be cleaned and the scabs removed. The hair should be cut and coated with coupling agent. When measuring back fat, place the probe water bag horizontally on the pig's back. The axis of the probe is perpendicular to the midline of the back. And make the front scanning line of the probe slightly exceed the midline of the back to show the strong echo of the spinous process: When measuring the eye muscle area, a probe with a scanning width of more than 10cm should be used. A water bag has been placed between the probe and the pig's back. Then adjust the contrast, brightness, gain, and near-field and far-field adjustment knobs of the B-ultrasound machine. After obtaining a clear ultrasound section sonogram, freeze the image. Use the electronic distance and area measurement functions to measure fat thickness and eye muscle area. Then use the annotation function to add ear number, breed, age, weight and other information. Finally, print or input into computer for storage.

4 Image recognition. Clear sonograms can clearly show the spinous process, vertebral transverse process and the four strong echo points of the longitudinal fascia of the lateral end of the longus dorsi muscle, as well as the skin interface. The fat connective tissue, the upper fascia of the longus dorsi muscle and the four strong echo bands. The fat layer is a band-shaped solid dark area: the muscle section is a solid dark area with slightly stronger echoes; the fat thickness and eye muscle thickness measurement point is 4cm away from the spinous process. The distance between the skin interface and the two strong echo bands of the upper fascia is the fat thickness: the distance between the strong echo bands of the upper and lower fascia is the muscle thickness. The eye muscle area measurement area is the solid dark area surrounded by the four strong echo points on both sides and the strong echo bands of the upper and lower fascia. Back fat thickness measurement. In the ultrasound image, 3 to 4 obvious strong echo bands can be seen, and the first one is the ultrasound reflection of the skin interface. The second line is the reflection of the interfat fascia. The third line is the reflection of the eye muscle membrane. According to the screen ruler, the vertical distance from the first band to the third band 4 cm away from the strong echo point of the spine is the back fat thickness. When measuring, determine the starting point and the end point, and the fat thickness in millimeters will be displayed on the screen. Eye muscle area measurement. In the ultrasound image, due to the strong reflection of the eye muscle membrane, a clearly visible, nearly elliptical eye muscle outline is produced. Since the upper and lower boundaries of the eye muscle fascia are directly opposite to the ultrasound emission line, a linear boundary is produced: however, only dot-shaped echo bands are produced at both ends. When measuring, first determine the short axis of the ellipse at the upper and lower boundaries, and then determine the long axis of the ellipse at both ends. The square centimeter value of the eye muscle area of the nearly ellipse is displayed on the screen. (V) Disease diagnosis Many diseases in pig farms can be preliminarily diagnosed by B-ultrasound, especially reproductive tract diseases. pigs use B-ultrasound to diagnose ovarian dysfunction or disease, uterine disease. As well as the boar's testicular and accessory gland diseases, other diseases such as liver and kidney lesions, internal and external masses, etc. B-ultrasound can be used for characteristic diagnosis.

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