3. To measure the long axis of the heart, the screen should display the maximum vertical axis value of the heart. As the gestational age increases, the fetal heart long axis increases regularly. The measurement method is as follows：

1. Keep the pig in a standing position. 

2. The probe is placed at the left or right side of the center of the abdominal wall of the ventral side, close to

the abdominal wall. If there is mud on the skin of this part, it should be cleaned with water first to prevent the

structure of the abdominal pelvis from not being correctly presented. 

3. The screen should be able to display the maximum vertical axis value of the stomach. As the gestational

age increases, the regularity of the fetal stomach long axis increases. 

The method of measuring the longest axis of the stomach is shown in the figure：

Procedure：

1. Clean up the excrement in the rectum of the bovine. 

2. A preliminary assessment of the pregnancy status is then made by hand palpation to determine the reproductive tissue that will be scanned with B-ultrasound. 

3. Hold the probe and insert hand and probe together into the rectum of the bovine. Hold the probe tightly to

ensure that any conditions that occur later can be felt first by hand, hand placed between the rectal wall and the

probe.

4. The internal structure of the cow is displayed on the screen, and the longitudinally intersecting part is the

bladder, followed by the cervical tissue and the uterus. Viewed horizontally, the uterine horn usually looks

circular. The probe moves inside the ventral back until the junction of the uterine horn and the uterus is observed, and then slowly deflects toward the uterine horn, as shown below:

The calculation method is consistent with BTD

DOG-GSD：Calculate gestational age according to the diameter of the gestational sac

1. Keep the dog on the side 

2. The examination position is in the position of the posterior nipple, and it is closely followed by the abdominal wall for left and right scanning.

DOG-CRL：Calculate gestational age according dog's CRL

The measurement method is the same as the bovine body length

DOG-HD：Calculate gestational age according to the dog's head diameter

The measurement method is the same as the cat's head diameter

DOG-BD：Calculate gestational age according to the dog's biparietal diameter

The measurement method is the same as the cat's biparietal diameter. After the measurement is completed, press the “Clear” button to clear the screen and exit the OBC table.

There are two ways to detect pregnant ewes with B-ultrasound：

For the detection of the abdomen, use a mechanical sector probe or a line array probe; for the rectum, use a

rectal probe. These two methods are useful for confirming whether pregnant or not. According to some published materials, we believe that both methods have proven effective in the diagnosis of pregnancy.

— The method of rectal examination within 35 days of pregnancy is more accurate than the method of abdominal examination；

— Both methods are equally useful within 35 to 70 days of pregnancy. — After 70 days of pregnancy, the method of detecting with the abdomen is better because the uterus becomes larger at the time and this method is more practical.

1. Abdominal testing can be performed while the ewes are standing or lying/sitting. The probe is placed in a predetermined area of the skin without hair on the skin in the middle of the abdomen. 

2. If there is mud on the skin of this part, it should be washed first with water to prevent the structure of the abdominal pelvis from not being correctly presented. 

3. The length of the trunk is measured. 

4. The distance value of the selected parameter is measured according to the distance measurement method.

ESD: Calculate gestational age according to skull diameter

The distance value of the selected parameter is measured according to the distance measurement method, and the corresponding gestational age data is automatically displayed on the left side of the screen.

Equine examination procedure：

1. Clean up the excrement in the horse's rectum. 

2. A preliminary assessment of the pregnancy status is then made by hand palpation to determine the

reproductive tissue that will be scanned with B-ultrasound. 

3. Insert the probe into the rectum of the horse with your hand and hold the probe tightly to ensure that any conditions that occur later can be felt first by hand, hand is on back side, between the rectal wall and the transducer. 

4. The internal structure of the horse is displayed on the screen, and the longitudinally intersecting part is the bladder, followed by the cervical tissue and the uterus. Viewed horizontally, the uterine horn usually looks circular. The probe moves in the ventral back until the junction of the uterine horn and the uterus is observed, and then slowly deflects toward the horn, as shown in the following figure:

5. The measurement method of the diameter of the gestational sac is as follows, and the measurement can be performed from the horizontal direction or the vertical direction. There is no difference between the two methods.

Measuring the diameter of the head is to measure the maximum diameter of the interior of the skull from between the ventral and dorsal sides. This diameter can be measured before 8 weeks of pregnancy. The method of measuring the diameter of the head is as follows：

After the formation of the fetal head, BPD measurement has become a routine for ultrasound examination. Measuring method：

1. The plane of the fetal head axis is scanned and the standard plane of BPD measurement is searched from

top to bottom. 

2. The distance value of the selected parameter is measured according to the distance measurement method.

HD：Calculate gestational age according to the dog's head diameter

The measurement method is the same as the cat's head diameter. 

BD：Calculate gestational age according to the dog's BPD

The measurement method is the same as the cat's BPD. 

GS：Calculate gestational age according to the diameter of the gestational sac

The measurement method is the same as the diameter of the equine gestational sac. 

CRL：Calculate gestational age according to the length of the dog's CRL

The measurement method is the same as the length of the bovine. After the measurement is completed, press the “Exit” button to clear the screen and exit the OBC table.