Breeding of bullfrog

Can be raised. First, the breeding of bullfrogs bullfrogs are hermaphroditic. When breeding, mature individuals "catch a pair" in the water, females ovulate in the water and males ejaculate in the water for in vitro fertilization, which is a typical representative of frog breeding. (1) The gonad development of bullfrog at sexual maturity usually takes about 8-9 months from tadpoles hatching to sexual maturity. In terms of weight, the female frog is more than 350g and the male frog is more than 300g g, but in fact, due to the differences in temperature, bait and feeding methods, the sexual maturity of bullfrogs is also very different. (2) Female characteristics in the sex identification site Male characteristics The tympanic membrane is the same as or slightly larger than the eye, and the first finger of the forelimb is underdeveloped. The first finger of unmarried tumor is very developed. The throat of the tumor is gray, the subcutaneous silent sac has a low yellow sound, and the subcutaneous vocal sac has a yellow-brown sound with obvious dark green spots. Slow growth, small growth and big growth? (3) Sex ratio: 2: 3, 1: 1 (4) stocking density: 5 pairs/10m2 (5) spawning ground S =10-20m2, H =1. (6) Oviposition habit: 1. Estrous behavior: under the influence of external environmental factors (such as temperature, light, etc.) ), both sexually mature male and female bullfrogs have obvious estrus behavior. The initial behavior of male frogs in estrus is constantly calling and summoning female frogs, with an average of more than 100 calls and chases per hour. Grab the female frog and touch her submandibular chest with your fingers, and the left and right forelimbs will quickly close and hug together. It can be seen that the marriage tumor on the inner side of the base of the first limb of the forelimb is particularly obvious and is flesh red. The female frog in estrus doesn't eat food, but jumps with the chirping of the male frog, sometimes making a "click" response, indicating that the female frog has a courtship request. Only at this moment will the female frog let the male frog jump on its back and hold the right hand. 2, hug: when estrus reaches its climax, men and women hug, usually in the middle of the night, and the hug time is generally as long as 1-2 days. 3. Oviposition and fertilization: The breeding season of bullfrogs is from April to September, and it is early and late in different regions. The external conditions for spawning are not high, and the key is temperature. As long as the water temperature reaches 20-30℃, both ponds and rivers can give birth smoothly. The ideal environment requires quiet, leeward, few pedestrians and aquatic plants on the shore. At the end of the hug, the female frog is stimulated by a foreign body, which is transmitted to the central nervous system through the sensory organs and then reaches the pituitary gland, prompting the pituitary gland to secrete hormones. Under the action of sex hormones, the female frog stares back hard, the abdomen contracts with the help of the male frog's breathing and cuddling, and the eggs are excreted. At the same time, the male frog excretes semen for in vitro fertilization. Ovulation time is 10- 20 minutes each time. Generally, individuals lay 20,000-30,000 eggs, with a maximum of 50,000 eggs. Bullfrog eggs are round and divided into two poles. Animals are extremely black and plants are gray. Some animals and some plants are at the top of the world, so eggs are black and white. A little numb. About 30-60 minutes after laying eggs, all the animals face up, which is called automatic transposition of eggs. If there are white eggs at the top of the plant after 2 hours, it is an unfertilized egg. According to this, the fertilization rate of bullfrog after spawning can be calculated, and the fertilization rate is generally above 90%. There are many reasons for oviposition without fertilization, mainly including: A, the male-female ratio is out of balance, the normal male-female ratio is 1: 1, the fertilization rate is over 90%, the fertilization rate of 2: 1 is 75-80%, and the fertilization rate of 3: 1 is only 40-50%. Too many or too few men will have an impact. B The male frog is too old, weak and old. Practice shows that the fertilization rate of the second frog is the highest, and the fertilization rate of the third to fourth frog is lower. C the water temperature is too low and the water quality is not clean. D The water surface is too wide for spawning. There are many ways to improve the fertilization rate, and artificial fertilization is an effective shortcut, and the fertilization rate can reach 90-95%. (4) Fertility The bullfrog has the greatest fertility among frogs. The absolute number of pregnant eggs of one-year-old bullfrog is about 6.5438+0.5 million, which increases with the increase of age, body length and weight. Linear correlation within a certain range. As shown in the picture, a one-year-old frog that has just reached sexual maturity weighs close to a two-year-old frog, but the amount of pregnant eggs is less than half that of a two-year-old frog. The absolute number of fertilized eggs is not only related to age and weight, but also varies greatly among individuals. Female frogs with good nutrition and normal development are better. Therefore, in order to obtain greater reproductive capacity, we must pay attention to the purification and cultivation of farmed frogs.

(5) The oviposition bullfrog lays eggs many times a year, and naturally lays eggs 3-5 times a year. Under the condition of artificial rearing, if the temperature can be controlled at 25-30℃, eggs can be laid all year round. (6) During the spawning season, bullfrogs keep chirping at night. At this time, it should be noted that the pond should be patrolled at dawn every morning, with light steps and slow movements, so as not to disturb the bullfrog's spawning. At the same time, pay attention to whether there are egg pieces and bullfrogs laying eggs by the pool. If the bullfrog is laying eggs, don't disturb it. Mark the spawning and egg mass of bullfrog. After laying eggs, collect the egg pieces according to the marks. When collecting and salvaging egg pieces, people should stand in the water, cut off weeds around and below the egg pieces with scissors, then gently insert the washbasin into the water below the egg pieces from the side of the egg pieces, and move the egg pieces into the incubation pool for incubation. Fish should be fished in time after the egg pieces are found, usually 30 minutes after spawning, otherwise the activities of breeding frogs, fish and other animals may make the egg pieces scattered or swallow frog eggs. Furthermore, due to too long time, the film becomes soft, and the eggs will sink to the bottom of the pool, reducing the hatching rate. (VII) Incubation equipment and preparation before hatching The incubation equipment for bullfrogs is simple, and the size depends on the number of eggs hatched, including porcelain pots, water tanks, wooden pots and fry cages. Specification 120cm×80cm×40cm. 40 mesh nylon net, fixed with wooden frame. Incubate in a cement pool. Before laying eggs in the pond, clean the pond to prevent sediment deposition, then pour in 30cm fresh water and spread a thin layer on the water surface with weeds such as peanuts to wash away the sediment. Its function is to support the egg pieces and prevent them from sinking. There is a shade shed above the pool to avoid direct sunlight and sudden change of water temperature. Put about 6000 fertilized eggs per square meter (about a nest). (VIII) Environmental conditions for hatching The hatching of bullfrog eggs requires certain environmental conditions. Appropriate environmental conditions can improve the hatching rate of tadpoles, otherwise the hatching rate will decrease. A water temperature: the suitable water temperature is 25-30℃, and 16℃ or higher than 34℃ is not allowed in hell. Tadpoles hatch at 19-27℃ for 3-4 days and at 25-30℃ for 2.5 days. BPH = 6-8.6。 C oxygen content = 3 mg/l or above. Second, the breeding of tadpoles The tadpoles that have just hatched are small in size, black in color and poor in swimming ability. As individuals grow up, their swimming ability will also be enhanced. So it takes about 10 days to move to the tadpole pond. Before tadpoles enter the pool, the pool should be cleaned and disinfected with 200PPM bleaching powder. If it is a mud pond, it should be disinfected with quicklime (75 kg per mu). After 7 days, the efficacy of quicklime disappears (and the water is tested), and then the tadpoles are put in. 1. Structure of tadpole pond: The pond for raising tadpoles can be cement pond or earth pond. The effect of cement leaving the pool is better. The pool area should not be too large. Cement pool should be 4-10m2. The earth pond is slightly larger,10-20m2, and the water depth is 40-80cm. The bottom of the pool is provided with a drainage hole, and the wall of the pool is provided with a water inlet. The wall of the pond has a certain inclination. Plant water hyacinths or water peanuts in the pool. The density is not easy to be too large. In order to raise tadpoles reasonably, tadpole ponds can be made smaller and more, so that they can be raised in batches according to the spawning situation. If there are no conditions, the spawning pond can replace the hatching pond. Bamboo, barbed wire and bricks must be used as barriers around the pool to prevent the enemy from escaping. 2. Stocking density: 1000-2000 tadpoles hatch 10 day /m2, 500- 1000 tadpoles hatch for 20 days /m2, 100- 150 tadpoles hatch for 30 days, the first time. Therefore, before hatching, the water quality should be fertilized to make plankton multiply. If the water is not fat, you can feed it with cooked egg yolk. Feed an egg yolk according to 10,000 tadpoles, once in the morning and once in the evening. Soymilk can be fed at 10- 15% of body weight for half a month, from 9: 00 am to 16: 00 pm. B. Water quality management: The tadpole pond requires good water quality, and the tadpole feces and residual bait should be removed in time to keep the water fresh, and the water should be changed properly to prevent the water quality from deteriorating. At the initial stage, the water depth was controlled at about 20-25 cm, and gradually deepened at about 30-40cm with the growth of tadpoles. 4. The second stage (from the age of 30 days to the completion of metamorphosis management) A Bait feeding: In this stage, in addition to artificial feeding of commercial feed, plankton must be cultivated as natural bait. The main feeds are: soybean milk, wheat bran, rice bran, silkworm pupa powder, fish meal, porridge, snail meat, fish, animal offal and so on. The feeding method is 100 tadpoles with 40-80g bait, of which animal bait accounts for 47% and plants for 43%. Throw 1-2 times a day, once in the morning or once in the afternoon. Share the bait on the table. B. Water quality management: the water in tadpole pond should be kept at 40-80 cm, and the water quality should be kept fat, lively, tender and cool. Replenish fresh water in time and adjust water quality. C daily management: pay attention to drainage and irrigation to prevent water level disorder caused by rainstorm or drought. The water temperature should be controlled below 35℃. If it is too high, replace fresh water or build a shed to cool down. Once in a while, after growing limbs, you should throw some boards such as water plants and water peanuts into the water for young birds to inhabit. Later, I moved to the young frog pond in time to raise it. If properly fed, tadpoles will grow into young frogs in about 70 days. During the feeding period, the pond should be inspected frequently to analyze its feeding situation and health status. If tadpoles are found to be sick, they should be isolated and treated in time. 5. Tadpoles can become young frogs during metamorphosis and overwintering, but if the feeding density is high, the bait is insufficient and the water quality is poor, the metamorphosis period will take 80-90 days. Especially during the spawning period in mid-July, the metamorphosis period will be extended to about 100 days due to the gradual decrease of temperature after August. This kind of delayed metamorphosis young frog is easy to die during the wintering period due to the decline of feeding metabolism and poor constitution. Controlling temperature and feed can accelerate or prolong the metamorphosis time of bullfrog tadpoles. The average water temperature is kept at 29-30℃ (when the water temperature reaches 35℃, it will affect the growth of tadpoles, when it reaches 38-39℃, it will weaken and when it reaches 40℃, it will all die. If more animal food is used, it only takes 40-42 days to become a young frog, but this young frog has a short development time and a small body. When the water temperature is kept below 25℃, adding more plant bait can prolong the metamorphosis time of tadpoles. Therefore, if it is a tadpole hatched in July, it is appropriate to extend the metamorphosis time of tadpoles. Make it fully develop into a metamorphosis in May of the following year. Although this young frog is a few months later than the early metamorphosis frog, the young frog is big and grows fast. Breeding of young frogs 1. Feeding of young frogs: The main key technologies are timely grading feeding and food training. The structure of the frog pond: the frog pond has an area of 20-50 square meters, a depth of 60-80 cm and a slope. The ratio of land and water area is 1: 1, which is for young frogs to rest and feed. A fence of 1.5m should be set around the pool. More frog ponds should be set up, so that they can be raised separately according to the size in the future, and the big ones should not be swallowed up by the small ones. 2, stocking density: tadpoles should be transferred to the young frog pond in time after metamorphosis. Generally, newly metamorphosed young frogs can put 80- 100 per square meter. After 30 days of metamorphosis, 30-50 young frogs weighing 25-50g can be released per square meter. In order to prevent food residue, feed in stages according to the size in time. 3, bait feeding: Young frogs and adult frogs have exactly the same feeding habits. They are used to eating live animal bait and will eat dead bait after domestication. The living foods that young frogs like to eat mainly include earthworms, maggots, small fish, shrimps, dragonflies, silkworm moths, locusts, grasshoppers, beetles and other insects. Artificial breeding of newly metamorphosed young frogs begins with taming. At the beginning of taming, live bait was released first, and then gradually mixed with dead bait to feed. A hanging frog began to die of bait; B, adding loach or small miscellaneous fish into the dead bait. At the initial stage of feeding, it is calculated as 5% of body weight. When the temperature rises to 20-26, the food intake of young frogs is the largest, and they are fed with 10%. When the temperature is lower than 18℃ or higher than 28℃, the food intake of young frogs decreases and they are fed at 5%. Feed 1-2 times a day at 9: 00 am and 16: 00 pm respectively. 4. Water quality management: the depth of the juvenile frog pond should be kept between 60 and 80 cm, and fresh water should be injected irregularly according to the change of water quality to keep the water fresh. Water hyacinth and other aquatic plants can be placed on the water surface, which can provide shade and purify the water quality. 5, daily management: shed shelter by the pool; B) Make some frog holes by the pool for young frogs to inhabit; C size should be graded to avoid killing; D strengthen patrol at night after rain to prevent young frogs from climbing the wall and escaping; Prevent the enemy from attacking. 6. Growth of young frogs: If young frogs can get enough bait and proper density in April to drive away enemies, the survival rate is very high. After half a year's growth, the body weight of the metamorphosed young frog can be increased by about 250g, and the body length is about 12cm. It will reach 500g after half a year.

7. Overwintering of young frogs: The hibernation of young frogs is mainly seasonal, mainly determined by temperature. Generally, when the air temperature and water temperature drop below 10℃, young frogs begin to hibernate, and when the warm spring environment is favorable in the following year, the air temperature and water surface temperature rise above 10℃, and hibernation ends. In artificial breeding, it is necessary to set up suitable wintering places to ensure the safety of young frogs, and at the same time put enough bait before wintering, so that frogs can accumulate enough nutrition and maintain metabolic consumption during hibernation. Four. Breeding of adult frogs 1. Structure of adult frog pond: 300 square meters is generally suitable. The depth of the pool water shall be kept at1-1.2m. There are many weeds (agricultural plants can also be planted) in the inland of the pool, and there are water inlets and water outlets. Set an escape wall with a height of about 1.5m to build a frog hole. 2. Stocking density: 10-20 per square meter of farmable animals. 3. Bait feeding: The adult frog has the same bait as the young frog, but the feeding amount is large. 5% from May to June; July-August 20%. 4. Water quality management: Like young frogs, the water depth in winter is about1m.. 5, daily management: the same young frog. 6, adult frogs overwinter: the same young frog. V. Diseases and Prevention of Bullfrog (1) Mycosis of Eggs 1. Symptoms: Gray hyphae around the egg mass will reduce the hatching rate and survival rate. In the case of poor water quality and continuous rainy days, the disease is prone to occur. 2, prevention and control methods: a to prevent water pollution; The incubation tank can be disinfected with potassium permanganate. (2) dermatomycosis 1. Symptoms: Hydromycosis enters from the wound of skin, parasitizes in the damaged part of tadpole epidermis, absorbs nutrition from skin and goes deep into muscle. Myxomycetes grow luxuriantly outward, forming a pale white cotton-like fungal layer visible to the naked eye. The sick tadpoles swim slowly, fidget and lose appetite, and then other bacteria will accelerate the wound infection and die. 2. Prevention and control methods: A, pay attention to prevent tadpole epidermis from being damaged; B, soak in 10ppm potassium permanganate solution twice a day for 30 minutes each time for 3 days. C is soaked in 5ppm water model mesh solution, and the method is the same as above. D, smearing the diseased tadpoles with 10% purple liquid medicine. (3) Tadpole fulminant septicemia (erythema) 1. Symptoms: Most of them occur in the bud formation period of tadpoles. There are many blood spots on the abdomen of sick tadpoles, especially near the abdomen and anus. When the condition is serious, transparent ulcer spots appear on the body, the eyeball is prominent and congested, and sometimes the tail is rotten. Gills turn white due to blood loss, abdomen swells and ascites is obvious. Before he died, he often circled on the water and sank into the water a few minutes later to die. Prevention method: disinfect with 20ppm quicklime regularly. Spray 0.44ppm dibromohydantoin on the whole pool. C 0.77ppm copper sulfate solution can be used in the whole pool. (4) gill rot of tadpoles 1. Symptoms: The diseased tadpoles have rotted gill filaments, and sludge and mucus are often attached to the gills, which makes it difficult to breathe. Sick tadpoles often swim alone on the water, move slowly, and often die from mixed infection with other germs. 2, prevention and control methods: a with 20ppm quicklime splash the whole pool; B, using 0.4ppm dibromohydantoin to splash in the whole pool; C feed mixed frog raw or compound changjiling 1% for 3-6 days. (5) Tadpole gastroenteritis 1. Symptoms: the disease often occurs in the stage when the forelimbs are about to grow. The sick tadpoles are fed with congestion and inflammation, the anus is red and swollen, the appetite is reduced, swimming is slow, and the mortality rate is high. 2, prevention and control methods: A depending on the water quality, replace fresh water, and regularly disinfect with 20ppm quicklime; B, collecting tadpoles and soaking them in 50ppm PV iodine for 5 minutes; Soak in 0. 1% salt solution for 30min; Feed with special frog medicine. (6) Tadpole rotifer disease 1. Symptoms: The diseased tadpoles are covered with rotifers, showing white tail, slow movement, isolation and difficulty breathing. Prevention and control methods: reasonably control stocking density, and cultivate in stages as soon as possible. B. Spray the whole pond with 0.77ppm copper sulfate solution. (7) Tadpole blister disease 1. Symptoms: The sick tadpole has swollen abdomen, lost its balance, floated on the water, and lost its normal swimming ability. Eating and other activities are difficult. Prevention and control methods: Tadpoles should be thoroughly disinfected before stocking. B. Change the water frequently to keep the water fresh. C, moving the sick tadpoles to fresh water, temporarily feeding and stopping eating. (8) Red leg disease 1. Symptoms: The diseased frog's hind legs are red and swollen with red spots or spots. Severe cases are complicated with various inflammations and ulceration. Sick frogs are listless, slow-moving, crouching or lurking in the water, unwilling to move or eat. Prevention and control methods: disinfect the pool water and feed table regularly. B, soaking the diseased frog in a bucket filled with 20% sulfanilamide solution for 2 days. C, spraying 0.4ppm dibromohydantoin 0.44ppm to the whole pond; Feed with special frog medicine. (9) Skin rot 1. Symptoms: At the early stage of onset, the skin on the body surface loses luster, the mucus secreted by the skin decreases, and the wettability decreases. After the appearance of white patterns, the body surface began to rot and fall off, local congestion and inflammation appeared, and the muscles in the back were exposed, which gradually spread to the trunk and even the whole back. 2, prevention and control methods: A with 0.4ppm dibromohydantoin 0.44ppm sprinkled on the whole pool; B, soaking the diseased frog in 2.5% salt solution for 2 hours for 3-6 days. C, soaking the feed in sulfanilamide solution for several hours, and then feeding. Feed with special frog medicine. (10) Gastroenteritis 1. Symptoms: At the beginning of the disease, the sick frog fidgeted, crawled around and liked to drill mud. Later, he lay by the pool, stretched his legs and closed his eyes, didn't eat, was slow to respond, rarely struggled after catching it, and often shrank his head and bowed his back. The abdomen and intestines of the sick frog are congested and inflamed, and there is no food in the intestines. 2. Prevention method: A soak in 3% salt water for 30 minutes for several days. B artificial feeding yeast stomach powder tablets twice a day, half a tablet each time, for 3 days. Feed with special frog medicine. (XI) Hepatomegaly 1. Symptoms: The diseased frog has fat appearance, stout hind legs and internal anatomy. The liver is extremely enlarged, which is 2-3 times of normal, with khaki, grayish white and light green bile. 2, prevention and control methods: a pool should be disinfected regularly; B. Soak in 20% sulfadiazine solution for 2 days or feed with 2g sulfadiazine per 10kg body weight. Meningitis (migraine) 1. Symptoms: the diseased frog has dark skin, anorexia, head tilting to the right or right, body out of balance, abdomen facing up, spinning in the water, tongue and stomach spitting out from his mouth when he dies, and no food on an empty stomach. 2, prevention and treatment methods: there is no effective treatment. (13) Cataract disease 1. Symptoms: The diseased frog has a layer of white membrane in both eyes, showing a "cataract" shape, and then becomes blind and cannot eat. 2, prevention and treatment methods: there is no effective treatment. (14) anorectal diseases 1. Symptoms: The diseased frog's rectum is exposed outside the cloaca, and it is inconvenient to move and emaciated. 2. Prevention method: Wash the exposed part with distilled water or cold boiled water, and then put it into cloaca to reduce its activity.