Bullfrog breeding

Cultivation techniques of Rana chensinensis in China and Rana chensinensis in America

At present, there are three breeding methods of Rana chensinensis in China: greenhouse breeding, outdoor farm breeding and field furrow sealing stocking. But the economic benefit of greenhouse cultivation is more obvious.

China Rana chensinensis mainly feeds on insects, while the living food of China Rana chensinensis cultured in greenhouse is mainly Tenebrio molitor, maggots and earthworms. Except for feeding Tenebrio molitor with bran, the other two kinds of bait can be fed with livestock manure or non-toxic organic garbage, which greatly reduces the breeding cost. Therefore, it can be said that forest frog breeding is a new industry with small capital and quick results.

The solar greenhouse investment is 6,543,800 yuan (400 square meters). Two rooms for breeding Tenebrio molitor, plus the feed cost of 5,000 yuan, can raise 8,000-65,438+10,000 young frogs, and about 20,000 female frogs can be released that year. According to the lowest market price of 5.00 yuan per frog, the output value can reach more than 654.38+10,000 yuan, which not only can recover the investment in that year, but also has a high economic return.

Bullfrog is native to North America and is the largest species of edible frog. Bullfrog grows fast, with delicious meat, rich nutrition and high protein content. Foreign bullfrogs include American bullfrog, swamp green bullfrog, spring bullfrog, African bullfrog, African bullfrog and so on. The individual weight of bullfrog can reach more than 1 kg. Bullfrogs like high temperature and damp shade, and live in the grass near the edge of the pond. They especially like to live in the semi-dry and semi-wet soil hole formed by water waves near the pond pit. Often the lower body is immersed in water, the head is exposed to the water, and the head is outward. The cry of a bullfrog is similar to that of a cow. When you hear the croak of the bullfrog, you can predict that the spawning period is coming, and then stop chirping after the spawning period.

Breeding of Bullfrogs and Breeding of Young Frogs (I) Breeding of Bullfrogs Bullfrogs begin to lay eggs from May to July. The optimum water temperature for spawning is 24-28℃, and the spawning time is 65,438+00-30 minutes. The amount of eggs laid varies with the individual size of the female frog bag, and generally thousands to 50 thousand eggs are laid. Eggs should be fished out 30 minutes after spawning. When fishing eggs, people should stand in the water, cut off all weeds around and below the eggs with scissors, and transport the eggs to the incubator with an egg picker to hatch. Incubation pond requires water depth of 50-60 cm and area of 1.2-2 m2, and it is suitable for incubating 6000 eggs per m2. For breeding eggs, the water temperature should be 20-30℃ and the pH value of water should be 7-7.5; The content of heavy metal ions shall not exceed the drinking water standard. Don't disturb the water body during incubation. Irrigation should prevent excessive flow and height, and shade shed should be built on the pool to prevent sun and rain.

2) Cultivation of tadpoles The newly hatched bullfrog tadpoles have poor swimming ability, and they have to be kept in the incubation tank for about ten days before they can be transferred to the tadpole pool. Tadpole ponds need to be cleaned and disinfected for 5-7 days before tadpoles can be put in. The pond should not be too big, 30-36 square meters is appropriate, and the minimum can be 6-8 square meters, and the water depth is 0.6- 1.2 meters. The suitable water temperature for tadpoles is 26-30℃. In order to keep the high temperature, it is necessary to build a shed, deepen the water level appropriately and change the water frequently. Tadpoles newly hatched 1000-2000 days are stocked per square meter, those hatched 10-20 days are stocked at 500- 1000 per square meter, and after 30 days, they are stocked at 100- 130 per square meter. Tadpoles began to eat unicellular algae after hatching for 4- 15 days. Later, all kinds of animal feed, such as snail meat, fish, animal offal, dead fish and so on. , can be added appropriately, and some rice bran, corn flour, bean cake, wheat bran, porridge and so on. You can add. Feeding amount: 40-70g of bait is fed daily within 7-30 days, and animal bait accounts for 60%; After 30 days of metamorphosis, every 100 tadpoles were fed with 40-80 grams of bait, and animal bait accounted for 47%. Once a day, 4-5 pm.

The breeding ground of commercial frogs should be in a cool place with sufficient water, no drought, no flood, wet, warm and sunny places and overgrown areas. Determine the area according to the number of aquaculture, and keep the water depth at 1- 1.2m in winter. The frog pond should be surrounded by reed curtain, bamboo fence or barbed wire, nylon net and brick wall. The fence should be buried at the height of 15-20cm and 1.5m to prevent the bullfrog from escaping. Ponds should be planted with lotus roots and other leafy emergent plants, and aquatic plants such as water peanuts and water lilies can also be planted. There should be a gentle slope of 1-2 meters between the water surface and the fence, and a frog hole should be built for frogs. Clay mud balls or bricks can be used as the skeleton, and a layer of mud should be coated inside and outside to avoid scratching the frog skin. The frog cave is parallel to the bottom of the pond, with a depth of 50-70cm, a width of 15-20cm and a height of 10- 15cm. There should be 2-5 cm of water in the hole. Frogs only eat live bait and need artificial supplementation. The methods are: 1, light trapping. It is best to use a 30-watt ultraviolet light or a 40-watt black light. When you turn on the lights in the dark, you can see the lively scene of bullfrogs jumping and devouring insects under the cluster lights. 2. Supplement small fish and shrimp. The first method is to dig a shallow pit near the frog pond and put in small fish and shrimp to supplement the lack of bait; Secondly, the trough bait tray made of wood and bamboo is nailed with nylon emery cloth at the bottom, and the water in the tray is connected with the pool water, fixed in the shade of the frog pond, and put in live fish and shrimp. When the weather turns cold and insects are scarce, this method is effective. 3. Insects such as locusts, mantis and mole cricket. After artificial capture, put it into the weeds in the frog pond and let the frogs feed naturally.

Prevention and treatment of frog diseases;

Red leg disease 1, symptoms: the frog moves slowly and its appetite decreases. The diseased frog has some subcutaneous bleeding on the abdomen and inner thigh. When the condition is serious, the leg muscles are obviously congested. Often complicated with diseases such as "gastroenteritis". 2. Etiology: Deterioration of water quality and high stocking density are important conditions to induce the disease. The main pathogens are Aeromonas hydrophila and Acinetobacter. 3. Harm: The disease has a long course and can occur all year round. The main onset season is from May to 65438+ 10. The incidence rate in coastal areas such as Ningbo is relatively high. If it is dry wintering, it will also happen during wintering. The incidence of red leg disease is generally 20-30%, and the mortality rate is between 20-50%, and the highest can reach more than 80%. 4. Preventive measures: (1) Change the water regularly to keep the pool water clean. (2) Properly control stocking density. With the growth of bullfrog, it should be cultured separately in time according to the size, water temperature and specifications of bullfrog pool, and the stocking density should be adjusted. (3) Disinfecting water with 3ppm potassium permanganate or 4ppm "Ranxiaoan" has a good preventive effect on the disease. (4) Adding "Ranbingning" and "SMZ" to frog feed has a good effect on sick frogs.

(2) rotten skin 1. Symptoms: At the beginning of the disease, the skin on the back of bullfrog loses luster and white spots appear. Then the epidermis fell off and began to fester, exposing the back muscles. The rotten spots are gray around, which can spread to limbs in severe cases. At the initial stage of frog eye pupillary lesion, granular processes appeared and gradually turned white until a white lipid film was formed to cover the eyeball surface. The sick frog can move at first, but in severe cases, it will refuse to eat until it dies. The time from illness to death varies with the size of the frog, usually 4- 15 days, and the elderly can reach more than one month. 2. Etiology: There are many reasons for this disease, mainly in the following aspects: (1) nutritional imbalance. Single feed and lack of trace elements, especially vitamin A and vitamin D, are the important causes of the disease. (2) The appearance is damaged, resulting in secondary infection of bacteria and fungi. (3) Primary bacterial infection. Acinetobacter calcoaceticus is one of the main pathogenic bacteria. 3. Harm: The disease usually occurs in young frogs below 150g, and the incidence of newly metamorphosed young frogs is higher. The time is generally from April to September, and the peak time of onset is spring and autumn. It has the characteristics of rapid onset and long course of disease. The incidence rate is between 20% and 50%, and the incidence rate is higher in frog breeding areas with silkworm chrysalis as the only feed. The mortality rate is generally 30-70%, and it can reach more than 90% when it is high. 4. Prevention and control methods: (1) Intensive breeding at the early stage of metamorphosis of tadpoles and proper addition of vitamin A, vitamin D, calcium, phosphorus, iodine and other trace elements in the feed can not only improve the metamorphosis survival rate of tadpoles, but also make the metamorphosis young frogs have strong disease resistance. (2) Change the water regularly, improve the breeding environment and disinfect the farm regularly. Disinfecting drugs are generally potassium permanganate, disinfectant, quicklime, malachite green, etc. (3) Adding vitamin A and vitamin D into the young frog feed to keep the feed fresh and diversified as much as possible, so as to keep the frog's nutrient intake balanced. (4) medication. If the diseased frog pond is disinfected with 4-5ppm of "Frog Xiaoan", the disease can be controlled after 4 days. Spraying the mixture of 3ppm potassium permanganate and glacial acetic acid in the whole pond can stop the death of the diseased frog and restore the health of the lightly diseased frog.

(3) fulminant hemorrhagic septicemia 1. Symptoms: There are obvious red bleeding spots in the abdomen of the sick tadpole, and the bleeding around the pharynx and anus is more obvious. In severe cases, there are almost transparent ulcer spots on the body surface, exophthalmos and congestion, and sometimes the tail rot. Gills are gray due to blood loss, abdomen is swollen, ascites is serious, liver and intestine are obviously congested, and there is a phenomenon of spinning on the water before death. 2. Etiology: The deterioration of water quality and high stocking density are one of the important causes of the disease. The pathogen is still unknown. 3. Hazard: The occurrence of this disease is explosive and highly contagious. The onset time is from mid-May to late September, and the water temperature is generally above 20℃. It only takes 2-3 days for tadpoles to get sick and die, and in severe cases, all tadpoles in the whole frog farm can die within one week. The main target of harm is tadpoles, especially tadpoles in metamorphosis, and young frogs also get sick from time to time. The epidemic of this disease was explosive in 1995. According to the investigation of nearly 1000 mu of aquaculture ponds in Guantang, Haiyan County, about 80% tadpoles broke out in spring, and the mortality rate reached 60- 100%, which was extremely serious. 4. Prevention and treatment measures: The cause of the disease is explosive and transient, and there is no effective treatment drug at present. Prevention should be the main way to reduce disease losses: (1) The tadpole pond should be cleaned before stocking. The drugs for cleaning the pool can be quicklime (50- 100ppm), Ranxiaoan (10ppm), strong chlorine essence (3-5ppm), etc. (2) Strengthen management and do a good job in site cleaning and disinfection. The inlet and outlet of each aquaculture pond should be separated independently, and the tools should be disinfected before and after use. Tadpoles are disinfected with 20ppm potassium permanganate before entering the pool to prevent infection by foreign pathogens. (3) Change the water regularly to keep the water quality good; Reasonable stocking and close feeding can reduce the incidence rate. (4) regularly adding drugs such as frog iodine, SMZ and cephalosporin into tadpole feed, and disinfecting the pond water with 2-3ppm mixed solution of potassium permanganate and acetic acid, which has certain control effect.

(4) Hepatitis (Oldham's disease) 1. Symptoms: There are no obvious symptoms in appearance, only the body color is dull and gray-black. Once the disease occurs, the bullfrog quickly stops eating, and the sick frog crouches in wet places such as grass, with weak limbs, limp whole body like a mass of mud, bloody and sticky spit in his mouth, often accompanied by the phenomenon that his tongue spits out from his mouth. Anatomical observation showed that the liver was severely discolored, or grayish white due to blood loss, or purple-black due to severe congestion. Bile is thick and dark green. There is no food in the stomach, only a small amount of mucus, and there is a phenomenon that intestinal segments are nested in the stomach. 2. Etiology: It is caused by bacterial infection. The frog pond is unclean for a long time, and the deterioration of water quality is an important factor leading to the disease. 3. Prevalence and harm: The clinical manifestations of the disease are acute and highly contagious. The onset time is from May to September every year, but it is more common in spring and autumn, and the main target is adult frogs over 150g. The time from onset to death of bullfrog is generally 2-3 days, and the mortality rate is extremely high. From 65438 to 0992, nearly 300 acres of adult frog ponds were found in Jiaojiang suburb of Taizhou, and about 60% of them became ill. During the period of 1995, more than 70% of the 600 mu frog pond in the area of Guangdeqiu village became ill. The fatality rate of bullfrogs in the two places is between 60% and 90%, which is extremely harmful. 4. Prevention method: Prevention is the main means to reduce disease losses, and the following measures can be referred to: (1) The bullfrog pond should be thoroughly cleaned and disinfected before stocking, especially in the old pond where the bullfrog has been raised for several years. (2) In the process of breeding, management should be carried out and water should be changed regularly to make the bullfrog have a good living environment. Frog farms and food farms should always be disinfected with drugs, such as "Fish and Shrimp Ning", "Frog Xiao An" and "Quicklime". (3) Put an end to feeding spoiled feed, and keep it fresh and diverse. All dead animals such as fish, shrimp and mussels can't be used as feed for bullfrogs. (4) When purchasing frog seeds, you should try to avoid bringing sick frogs into your own farm. Bullfrogs should be disinfected in vitro before entering the pool. The disinfection method is generally to soak in 20ppm potassium permanganate solution for 20 minutes. (5) The farm should have a disinfection pool or tank, and the tools should be disinfected in time before and after use to avoid cross-use and borrowing of tools. (6) If the bullfrog is sick, the sick frog and the dead frog should be fished out in time for disinfection, and "Frog Xiao 'an" or "Frog An Powder" should be used as the whole pool for disinfection. (7) The disease can be effectively controlled by mixing Ranganning with frog pond and disinfecting water with disinfectant.

(v) Meningitis 1. Symptoms: The diseased frog has dark complexion and loss of appetite. Its typical clinical symptoms are that the neck leans to one side, the body loses its balance, the abdomen is upward, and it is swirling when flowing in water. Anatomical observation showed that the liver, kidney and intestine of the diseased frog were congested. 2. Etiology: bacterial infection. The main pathogen is Flavobacterium meningoencephalitis. 3. Hazard: The disease was first discovered in Shanghai, and occurred in Jiaxing and Huzhou during 1994 and 1995. The main target of its harm is the giant frog with a weight of100g, which is highly contagious. The onset time is usually from July to June, and the water temperature is above 20℃. The time from onset to death of bullfrog varies with the water temperature, usually 4-7 days, and it can be extended to more than 15 days when the temperature is low. During the period of 1994, more than 40% frogs were infected with the disease in a frog pond of about 400 mu in Qianjin Township, Huzhou, and the mortality rate was between 40% and 90%. 4. Prevention and control methods: (1) Disinfect the frog pond regularly and change the water regularly. Disinfecting drugs can refer to the use of "strong sterilization disinfectant" and "mixture of potassium permanganate and acetic acid". (2) The drug "Ranbingning Ⅱ" was mixed into the feed, which had a significant therapeutic effect on the disease. (3)SMZ, RAN Bingning and other drugs also have a certain effect on the disease.

(6) Ascites 1. Symptoms: Abdominal swelling of tadpoles and serious ascites are the main symptoms of this disease. Anatomy showed that the intestine expanded obviously, there was nodular obstruction near the anus of the posterior intestine, and there was no obvious change in the liver and gallbladder. After tadpoles get sick, their activities are obviously weakened and their food intake is reduced. 2. Etiology: The pathogenic pathogen is unknown, and bacteria have not been isolated from the liver tissue of diseased tadpoles. 3. Prevalence and harm: The harm object of ascites is tadpoles. After investigation and comparison, the incidence of tadpoles after wintering in autumn last year was significantly higher than that in spring that year. The disease usually occurs in spring and summer (April-August), and the water temperature is above 20℃, so it is highly contagious. The time from onset to death of tadpoles is generally 3-5 days, and all tadpoles in individual ponds die within one week. 1in the spring of 1996, Haiyan and Huzhou developed diseases almost simultaneously. The tadpole culture pond of about 160 mu in Qianjin Town, Huzhou City was investigated. Among them, 1 10 mu suffers from ascites, the incidence rate is 70%, and the mortality rate of tadpoles is generally between 30-70%, with the highest being 65438+. 4. Prevention method: Prevention should be the main way to control the disease. (1) reasonably control the stocking density of tadpoles, change water in time, and keep the water fresh. (2) Tadpoles were not introduced from epidemic areas, and were disinfected with potassium permanganate before being put into ponds. (3) Soak the feed before feeding to ensure that the feed is diverse, palatable and fresh. (4) Disinfect the pond water with PVP- iodine 1-2ppm after the onset of the disease, and mix cephalosporin or PVP- iodine into the feed for feeding.

Nine tricks to solve frog food

Now frog farming is more common, and the development of animal feed is an important link. Nine ways are introduced for farmers' reference.

1, cultivate earthworms.

Put cow dung, rotten fruit and rice washing water on the land of bullfrog pond. , mixed with soil, add earthworms and let them reproduce. Earthworms can be hunted by bullfrogs when they are unearthed at night after a period of cultivation. You can also use scattered wasteland and apply enough cow dung to cultivate earthworms, which can produce 5 ~ 7 kilograms per square meter.

2. Light catches insects.

Hanging a 30-watt black light or purple light above the table in the frog pond, 23 cm away from the water surface, can attract insects, rice planthoppers and so on. At night, bullfrogs gather under the lights to hunt. This method works best in May-September, and the lights should be turned on until midnight after sunset, and there are more dew and fewer insects in the latter half of the night, so it is necessary to turn off the lights to save electricity.

3. Cultivate Ampullaria gigas.

You can also use sporadic ditch ponds or build small ponds to breed and breed in frog pond water. In high temperature season, a pink egg mass is produced every 5 ~ 10 day, and each egg mass has about 1000 eggs. When the eggs break through the membrane, snails will be used as feed for bullfrogs.

4. Raise silkworms.

Planting mulberry trees and raising silkworms in front of and behind the house. Silkworms grow fast and can't live for about 20 days. Young silkworms can be used to feed young frogs, and when they are 4.5 to 5 years old, they can be used to feed adult frogs.

5. Feeding Tenebrio molitor.

Tenebrio molitor is the best feed for bullfrogs, which is easy to feed. It can be fed only with wheat bran and cabbage leaves. However, the growth of insects is slow, so it is necessary to expand the feeding quantity to ensure the feed supply.

6. Lure flies to breed maggots.

Hanging pots, trays, etc. 30 cm above the bullfrog culture pond, bait such as waste animal meat and fish viscera is put in to lure flies to breed maggots. When maggots climb out of the pot and fall into the water, they become delicious for frogs. You can also build a small pond, put bean curd residue in the pond, and then put rice washing water. Cover the surface of the pond, and you can feed the bullfrogs with maggots in a few days.

7. Cultivate Daphnia.

Daphnia, commonly known as "red worm" and "fish worm", is an ideal feed for tadpoles. Drain the water in the breeding pond first, clean and disinfect the pond, and then sprinkle 1kg (or other livestock manure) of dried chicken manure and bean curd residue on every square meter in the pond. It is best to expose the pond to the sun for a week, then irrigate it for 40cm and put in the provenance of Daphnia. After a few days, the pool water will turn green, and a large number of Daphnia can be bred in the pool water within two weeks.

8. Use leftovers.

Disinfect and mash the leftovers from slaughterhouses and restaurants, and mix them with mixed feed to feed. Where there is a silk reeling factory, silkworm chrysalis can be used as feed, and pig lungs and bovine lungs can also be bought and chopped for feeding.

9. Catch small fish and shrimp.

Farms located near rivers, lakes or fish ponds can often catch wild fish and shrimp as feed.