Key Points of Artificial Breeding Technology and Management for Leeches (Medicinal Leeches)

Leeches, also known as medicinal leeches, make their living by sucking blood and preying on small animals, and after processing they are a valuable traditional Chinese medicinal material. In recent years, artificial breeding has emerged. So, what breeding technology is there for leeches? Let's find out together!

1. Site Construction

Choose a wind-sheltered, sunny spot with convenient drainage and irrigation to build the pond. The ridge around the pond should be 1.8 m high, with a water depth of 1 m. The area should be determined according to the breeding quantity; generally, 60,000-100,000 young leeches can be stocked per mu of water surface. Set an inlet and an outlet at opposite corners of the pond. To facilitate the leeches' habitat and egg-laying, some irregular stones or branches can be placed on the pond bottom. In the water, 5-8 earthen platforms should be built 20 cm above the water surface, each about 1 sq m. The pond ridge should also have an escape-prevention ditch, built with bricks, 12 cm wide and 8 cm high. When it rains, cover it with fine mesh netting or spread some lime in the ditch to prevent escape.

2. Stocking and Release

The source of leech seedlings can be capture, purchase or self-breeding. At the beginning of breeding, natural capture is generally the main method, and they can also be purchased from relevant units. For artificial breeding, the golden leech is preferable; the golden leech has a large body and high yield, commonly known in rural areas as the “cow leech”, often crawling on cattle to suck blood. When capturing for breeding stock, attention should be paid to identification. Leeches are hermaphroditic, and each leech can lay eggs and reproduce. Early spring release is advisable; stocked in early spring, they can grow to full size by October and be processed for sale.

3. Breeding Management

1. Building a Breeding Pond

The pond area is best around 30 sq m, built as a square of 5×5 m or 6×6 m. Around the pond along the walls, set a platform 1-1.5 m wide, with water in the middle, water depth 50 cm, and the platform 2 cm above the water surface, keeping the platform surface moist. The soil used for the platform should be loose sandy soil rich in humus, convenient for the leeches to burrow into; yellow clay must not be used. At the level of the platform surface, an overflow outlet should be set to prevent rainwater from submerging the platform and causing breeding failure.

2. Selection of Breeding Leeches

For use as breeding stock and breeding leeches, the age should be over 2 years, body weight around 30 g, with a robust constitution, lively and active, quickly shrinking into a ball when touched by hand. Such leeches carry many eggs and have a high hatching rate. The stocking amount of breeding leeches is calculated according to the land area of the platform in the pond; generally about 1.5 kg per sq m. After the breeding leeches are put into the pond, the water quality should be kept rich and fertile, with sufficient plankton and snails for them to feed on, so as to increase the breeding quantity.

3. Breeding Management

In the middle and lower reaches of the Yangtze River, the time for leeches to lay egg cocoons starts in early May and continues until mid-June, with mid-May being the peak breeding period. During the egg cocoon laying period, quiet should be maintained, avoiding walking along the bank and causing vibrations; otherwise, leeches in the process of laying egg cocoons will be startled and flee, resulting in empty cocoons and breeding failure.

4. Hatching Management

After leeches lay egg cocoons, they can be collected and captured for keeping in another pond or for processing. The breeding pond also serves as a hatching pond; the egg cocoons are left to hatch naturally in the burrows. About 11-15 days after the egg cocoons are laid, young leeches hatch out. The newly hatched young leeches resemble the adults in body shape, are cork-yellow in color, and have 7 thin purple-gray longitudinal stripes arranged on each side of the back.

4. Feeding Technology

1. Feeding Bait

Leeches mainly feed on invertebrates such as snails and earthworms and on the blood of mammals. Natural feed is mainly snails, supplemented by earthworms, insect larvae, etc. Artificial feed is various animal blood. After feeding is completed, the coagulated blood residue should be removed promptly to avoid polluting the water quality.

2. Regulating Water Quality

Leeches are easy to keep alive and are not strict about the environment and water quality. The water temperature should be kept at 15-30 degrees; too high or too low will affect growth. However, artificial breeding density is high, so it is better to keep the water quality clean and ensure a certain dissolved oxygen content. In addition, in July-August the water temperature is high, so attention should be paid to appropriately changing the water to lower the water temperature.

3. Overwintering Management

After the beginning of winter, when the temperature drops below 10 degrees, leeches stop feeding and burrow into the soil or under fallen leaves to hibernate. For overwintering by draining the water, cover the pond surface with straw or wooden poles to prevent freezing and keep the soil moist. For overwintering with ice, the pond water should be appropriately deepened to prevent complete freezing.

The above is the leech breeding technology compiled for you by the editor. Hope it can help you!