Detailed Explanation of Key Points for Efficient Artificial Breeding of Field Frogs
The local frog, commonly known as the field frog, is mostly the black-spotted frog (a type of local frog) in artificial breeding today. To resolve the conflict between protecting wild frogs and market demand, many places are now developing artificial frog breeding. The techniques for artificial frog breeding are as follows.
Construction of the Frog Pond
The size of the frog pond can be flexibly determined according to actual conditions. The pond should be enclosed with brick walls on all sides, with a wall height of over 1.5 m, to prevent frogs from escaping or snakes from entering to prey on the frogs. It is best to build the frog pond near a residence for easy management. A water inlet and a water outlet should be set at each end of the pond respectively, and sealed with iron rods and fine-mesh nylon netting to prevent escape. Aquatic plants and small shrubs should be planted around the inside of the pond to provide convenient habitat for adult frogs.
Care of Breeding Frogs
Before the severe cold of winter arrives each year, the pond water should be drained, but the pond should be kept constantly moist, creating favorable conditions for breeding frogs to burrow into mud holes for hibernation.
Breeding Larvae (Tadpoles)
After the Awakening of Insects solar term in spring each year, an appropriate amount of live water should be let into the frog pond to allow female frogs to breed tadpoles. After tadpoles are produced, the breeding frogs should be isolated to prevent them from swallowing the tadpoles.
Bait Feeding Management
1. Feeding live feed: Since small tadpoles feed on small animals, some water fleas, mosquito larvae or tadpoles of other small frog species, etc. should be regularly placed in the pond for them to eat. These small animals can generally be caught in paddy fields, ponds, stagnant ditches and other waters.
2. Feed must be sufficient: Since small tadpoles will eat the smaller ones and engage in mutual cannibalism when food is lacking, feed must be supplied in sufficient quantity so that small tadpoles always have feed available to eat.
3. Graded rearing: Since frogs are fierce by nature, the phenomenon of the strong preying on the weak, such as large frogs eating small frogs, is very common. To eliminate this phenomenon, graded rearing should be adopted, keeping frogs of the same size enclosed together for rearing, and feed should be supplied in sufficient quantity so that they can all eat their fill and will not prey on each other.
4. Sources of feed: Frogs have very omnivorous feeding habits; earthworms, insects, small fish, small shrimp, small crabs, small snails, small mussels and so on are all their delicacies. To ensure the source of feed, one can contact vendors near nearby towns and markets who sell water-basin chicken and duck, give them a modest deposit, and ask them to collect the chicken and duck crop and small intestine and lungs, etc. discarded each day and provide them, which are then chopped up as feed. One can also boil some tea seed cake water and pour it into fertile soil near banana roots, tree roots or garbage piles, and before long many earthworms will come burrowing out, ready to be caught as feed.
5. Feeding location: Since frogs like to catch food in water and do not like to catch food on land, the feed should be placed on the water surface of the pond, making it convenient for frogs to catch food.
6. Precautions: The bottom of the frog pond should be lined with fertile soil several tens of cm thick; strictly prevent water polluted by pesticides, chemical fertilizers or industrial wastewater from flowing into the frog pond. The frog (black-spotted frog) grows and develops relatively quickly. As long as sufficient feed can be guaranteed and management is proper, under normal circumstances, small tadpoles produced in early spring can metamorphose into young frogs by summer, and after careful artificial rearing, by the end of the year the individual weight generally can reach over 50 g. When raised until winter when prices are high, they can be marketed for sale.
Feeding and Management of Field Frogs
1. Feeding and Management of Tadpoles
For artificially reared edible frogs, rearing must start from artificial egg collection followed by hatching and nurturing; after emerging from the membrane, the tadpoles are cultivated in the original hatching pond or net cage, with 600-800 tails stocked per sq m of water surface. Artificial feeding begins on the 4th day after the tadpoles hatch, and the tadpoles need to be raised for one week before being transferred to the rearing pond. After about 20-30 days, they gradually take red worms, water fleas and fly maggots as the main food, and can also take soybean milk, soybean residue, soybean cake powder and chlorella as the main food; adding a certain amount of fish meal can promote their growth. Generally, for every 10,000 tails, 15 cooked eggs are crushed and sprinkled with water for feeding 1-2 times. After the 5th day, switch to a compound feed of soybean milk, wheat bran and tofu residue, or feed such as rice bran and fish meal, fed 1-2 times per day, with the feed placed on feed trays; powdery feed should first be mixed with water into a viscous state before being sprinkled for feeding.
① Management of tadpoles. When bubbles are found in the pond water or the water quality has a rotten smell, new water should be replaced immediately, generally once every 3 days; during dry weather lasting many days and continuous high temperatures, replace the water once every 2 days.
② Management during the metamorphosis period. About 70 days after the frog eggs hatch, they become young frogs. During the stage from the appearance of the forelimbs in tadpoles to complete metamorphosis, they mainly absorb nutrition from the tail, use lungs to breathe air, and begin to jump out of the water to land and rest. When more than 90% of the tadpoles have become young frogs, they can be transferred to the young frog pond for rearing.
2. Feeding and Management of Young Frogs
① Intensified domestication. With high-density centralized enclosure rearing, a density of 100-150 frogs per sq m can be used, kept in a cement pond with smooth inner walls and a height of over 1 m, with a water depth of about 20 cm, feed trays placed on the water surface, and no land area inside the pond, forcing the young frogs to come onto the trays to gather for feeding and resting.
② Bait training for feeding. First feed live bait for 1-2 days, then on the 3rd day begin adding 20% artificial feed to the bait, and increase the proportion day by day thereafter; after 10 days increase to 80%. "Live bait" mainly includes earthworms, fly maggots, small fish and shrimp, insects, snails and loaches, etc.; "dead bait" refers to dried silkworm pupae, animal offal and compound feed, etc. Using movement to carry stillness, the "dead bait" is activated, and finally they transition to completely feeding on artificial bait. At the same time, feeding is required to be timed, quantified and fixed in location. Feeding time: in spring and autumn around noon, in summer in the evening or morning, 1-2 times per day, and each feeding should be finished by the young frogs in about 1 hour. For young frogs weighing under 50 g, the feeding amount should account for 6-8% of body weight; for young frogs weighing over 100 g, the feeding amount should account for 8-10% of body weight. The bait is required to be fresh, clean and nutritious.
③ Screening, grading and separate rearing. When young frogs have been domesticated for 20-30 days, the pond water should be drained, and large-sized young frogs should be transferred to the adult frog pond at a density of 60-80 per sq m for rearing; small-sized young frogs remain in the original pond for domestication. Using feed and indoor three-dimensional, multi-layer box and cage intensive rearing is a new method of frog farming. Raising frogs in plastic boxes and wooden boxes for small-scale farming gives extremely high yields, with several hundred frogs able to be raised per sq m; generally from hatching to adult frog takes only 5 months.
3. Feeding and Management of Adult Frogs
After young frogs are transferred to the adult frog pond, the frogs have a large food intake and their growth speed accelerates, which is an important period for forming commercial output. In addition to supplying sufficient bait, when tadpoles metamorphose into frogs it is necessary to increase the feeding of animal feed, mainly artificially cultured fly maggots, earthworms, red worms, chlorella water fleas and other live baits with high protein and high reproduction rates. When live bait is insufficient, mixed feed can be used in combination, such as 60% rapeseed cake (powdered), 30% rice bran (or wheat bran), 5% soybean powder and 5% fish meal mixed evenly, with relatively good results. Tadpoles are active in the water; after 5 days they can be supplied with refined feed, including soybean milk, egg yolk, water fleas, water spinach, tomatoes and aquatic plankton.
In addition, when raising earthworms on soil mounds, as long as some lime water at a concentration of 3-5% is sprinkled in sections on the soil mounds every evening, the earthworms will come out in full force and serve as frog bait. An appropriate amount of compound feed should also be fed, and timely separate rearing and adjustment of rearing density are needed. After adult frogs have been raised for 1 month, when the frog body weight reaches 100 g, the rearing density is 30 per sq m; after 2 months, change it to 10-15 per sq m. After a further short period of rearing, they can become commercial frogs for market.
Breeding Techniques
The key to frog rearing techniques is artificial breeding, because wild field frogs often have a parasite called Diplostomulum spataceum parasitic in the frog's muscles; using the method of artificial egg laying and isolating adult frogs can effectively prevent this disease. Stock at a density of about 1 group of breeding frogs per 3 sq m (stocking before May is better). Breeding frogs are required to be large in size, and parent frogs that have been producing for 1-2 years are best. The mixed stocking ratio of females to males is 3:1, and the stocking density is relatively lower than that of meat frogs. From young frog to sexual maturity takes about three years.
1. Management of breeding frogs: Strengthen the feeding of protein feed, mainly earthworms, supplemented by moth-attracting worms. Maintain the normal balance value of the pond water, requiring it to be fertile and lively. When the water temperature is set at about 22°C, prepare well for egg laying and hatching (at this time male frogs croak continuously). Female frogs over 50 g can lay many eggs at one time. Generally a male and female in amplexus lay eggs on aquatic plants. Frog eggs are light yellow, round, and attached in sheets to gelatinous egg membranes floating on aquatic plants, and are very easy to identify.
2. Egg laying: The artificial egg-laying site needs a still-water area; generally the cage-type egg-laying method is used, that is, forcing the frogs to lay eggs in baskets or cages. With a female-to-male frog ratio of 1:1, for 20 sq m of egg-laying area, 5 egg-laying baskets or cages can be placed; the pond water depth should be kept at 10-15 cm, and the water temperature should be kept at 10°C-11°C. To increase the hatching rate, the egg sheets can be protected with a surrounding net to prevent parent frogs from disturbing them and causing them to sink.
3. Hatching: During the hatching period, the temperature for fertilized frog eggs should be kept at 20°C-28°C, mainly natural hatching; the plastic film mulching hatching method and the waterless hatching method can also be used. Generally after 3-5 days all tadpoles can hatch. Newly born tadpoles depend on the egg membrane for safe survival, so do not stir the pond water casually. After all frogs have laid eggs, catch the frogs out of the pond promptly to avoid interfering with hatching and the tadpoles' living environment. After the eggs hatch for 5 days, refined feed can be supplied, such as soybean milk, egg yolk, water fleas and aquatic plankton, fed 2 times per day, but the feeding amount should not be too much, to avoid water quality deterioration causing tadpole death. After tadpoles are raised for 1 week, they can be transferred to the rearing pond for rearing.