veterinary B-ultrasound observation of the formation and degeneration of the corpus luteum in dairy cows

1. Follicles and uterine mucus during estrus

The follicles under veterinary B-ultrasound images are low-echo liquid dark areas, and the small amount of echo in the uterine horns is estrus mucus

2. New corpus luteum after ovulation

The new corpus luteum is mostly with a liquid cavity, and the cavity is large. Under veterinary B-ultrasound images, there may or may not be strong echoes around the regular structure of medium-density or low-density tissue

3. New corpus luteum and follicles

Evaluation of follicles in this new corpus luteum state: 1.79cm follicles were once cystic (FSH peak), and are now in an aging or static state (not enough to ovulate at the LH peak that just occurred).

4. Corpus luteum on the third day after ovulation

The liquid cavity in the corpus luteum is large, and there are regular, uniform, fine and medium echoes around the liquid cavity.

5. Corpus luteum on the 6th day after ovulation

Under the veterinary B-ultrasound image, the liquid cavity gradually shrinks, and the echo is more obvious, showing a ring-shaped structure

7. Corpus luteum on the 7th day after ovulation

Under the veterinary B-ultrasound image, the liquid cavity is round, the ring is regular and clear, and small follicles develop

8. Corpus luteum on the 8th day after ovulation

Under the veterinary B-ultrasound image, the liquid cavity is further reduced, the ring is further enlarged, and linear or ring-shaped strong echoes begin to appear around the liquid cavity. There are also small follicles developing. The diameter of the corpus luteum is measured to be 3.46cm. At this time, the diameter of the corpus luteum should be much larger than the diameter of the mature follicle 8D ago.

9. Corpus luteum on the 10th day after ovulation

Under the corpus luteum conditions at this stage, if there is a dominant follicle development, it is necessary to track and observe whether this follicle will mature and whether the corpus luteum will degenerate.

10. Corpus luteum on the 11th and 13th days after ovulation

11. Corpus luteum on the 15th day after ovulation: will degenerate

Under the veterinary B-ultrasound image, the liquid cavity disappears, the echo of the corpus luteum tissue begins to be uneven, and the diameter of the corpus luteum may begin to shrink. The follicles develop further.

12 Corpus luteum on the 16th day after ovulation: will continue to be generated.

The liquid cavity in the corpus luteum almost disappears, and the corpus luteum tissue has a medium echo and is slightly enhanced. Most corpus luteum tissues have trabeculae. Veterinary B-ultrasound images show linear strong echoes from the liquid cavity

13. Corpus luteum on the 17th day after ovulation

The corpus luteum tissue degenerates, the veterinary B-ultrasound echo is uneven, and the boundary echo is irregular. The dominant follicle is about to mature.

14. Degenerated corpus luteum

The corpus luteum has atrophied (corpus albicans), and the veterinary B-ultrasound echo is uneven, and the volume is reduced.