How do sows reproduce and have more babies?
1. Variety first, survival of the fittest.
Taihu pig and other high-yield varieties and individuals were selected, with an average litter size of 15.83 and a maximum litter size of 42. The litter size of foreign large white pig is 1 1 ~ 12. This is an effective method to improve the reproductive rate of sows. In individual selection, the study shows that the effective nipple number of sows is directly proportional to the farrowing rate. Choose a good sow, like a breeding pig, and choose a sow that conforms to the characteristics of this breed, is strong, symmetrical, gentle, with straight nipples, straight back and waist, big belly and no mopping the floor.
Third, make full use of heterosis. The first generation produced by hybridization between different varieties or strains has higher vitality and growth intensity than their parents, which is heterosis. Landrace pigs with high lean meat rate and fast growth rate can be selected to cross with Yorkshire sows to produce "grown-up" binary hybrid sows, which have good maternity, strong reproductive ability, litter size of about 12, good lactation performance, rough feeding tolerance and strong adaptability, and the lean meat rate is over 65%, so they are excellent female parents for producing commercial pigs. Duroc boars in Taiwan Province Province can be selected to produce pure foreign ternary (Du Changda). Such ternary pigs gain weight quickly, not less than 800g/ day, and the feed reward is high, reaching 2.8 ~ 3.0: 1, thus greatly shortening the fattening period, reaching the goal of listing 90kg in five months, reducing the cost of raising pigs and obviously improving the benefits.
2. Reasonable nutrition, obesity control, short-term optimal feeding and ovulation increase.
It is very important to strengthen the management of sow feeding. Sows are fed roughage during empty pregnancy, second trimester of pregnancy and later lactation, and green feed is appropriately fed; During pregnancy, protein, concentrate rich in minerals and vitamins, green and juicy feed should be adequately supplied, but not too much energy, otherwise it will affect the intake during lactation and reduce lactation capacity. At the same time, it is necessary to provide a relatively stable living environment for sows and minimize external stimuli such as herding, driving and fighting.
Overweight sows: can lead to small litter size, low survival rate, small weight, uneven, severe diarrhea and low milk production. Sows are too thin: the fetus is stunted, and the weight of sows will drop soon after delivery, and in severe cases, postpartum paralysis will occur. How to control this situation? Staged feeding can be adopted to create conditions for high yield of sows. The gestation period of sows (1 14 days) includes: the first trimester (from mating to the first month), the second trimester (from 2 to 3 months) and the third trimester (from the last month). Feeding sows full-price high-quality feed10–15 five days before breeding can increase ovulation (short-term excellent feeding can increase ovulation). In the early pregnancy, that is, the first month after pregnancy, low nutrition level feeding, daily feeding 1.8kg ~ 2.2kg. But the content of protein in feed is not lower than 13% ~ 14%. If the weight is poor, it is still necessary to give high nutrition. In the second trimester of pregnancy, sow's appetite increases, its metabolic function is vigorous, and its feed utilization rate is improved. Feed with moderate nutrition level can be given, including protein 14%~ 15% and 2.5 kg/day/head. After entering the third trimester of pregnancy, the fetal weight and length increase rapidly, accounting for about 2/3 of the birth weight. At this time, sows should be fed with a slightly higher nutritional level, 3 kg/day/head, and the crude protein content is 16%~ 18%. This method has a great effect on controlling sow fat, increasing litter size, promoting fetal protection and improving the weight of newborn piglets.
At the beginning of estrus, intramuscular or subcutaneous injection of 500–1000 iu of chorionic gonadotropin can increase ovulation, pregnancy rate and litter size.
Third, timely breeding to improve the conception rate.
1. sow's first mating age: premature mating has many consequences: small litter size, many stillbirths, small newborn weight, weak constitution and slow growth; Sows themselves are stunted, aging before they are old, and the breeding period is shortened. Mating too late will reduce the number of babies.
Local sow: 6~8 months old, weighing more than 70kg (generally more than 70% of adult weight is required);
Pig breeds and their hybrids bred in China are about 7 months old. The hybrid weight is not less than 80 ~ 100 kg;
Foreign medium-sized pigs: such as Middle Yorkshire (adult sow 2 10 ~ 250 kg), 8~ 10 months old, and weight 100kg or more;
Large Yorkshire and other exotic pigs (also known as large white pig, adult sow 260 ~ 330 kg): weight 120kg.
The age of first mating can also be determined according to estrus: it is best to mate at the first estrus and the third estrus after the second estrus.
2. How to grasp the timing of timely breeding: First of all, we should do a good job in estrus identification of sows in management. An estrus cycle is divided into four stages: pre-estrus, estrus, post-estrus and bisexual (estrus). An estrus cycle is 18 ~ 23 days, with an average of 2 1 day. Among them, the mating time is in estrus, also called intermediate estrus. Estrus is the climax of the sexual cycle. This period generally lasts 2~4 days, with an average of about 3 days (ranging from 0.5 to 7 days). Only in this period can we accept the crawling and mating of boars. Among them, the climbing time is about 2.5 days (52~54 hours on average) (except for very short estrus). In estrus, sows are excited and full of sexual desire, such as looking for boars, accepting boars to climb and allowing mating; The vulva is congested and swollen, and mucus flows out of the vulva. When the mucus changes from water to viscous, it means that it has reached the adaptation period. If you press your waist with your hands, the sow will stand still, which is a concrete manifestation of accepting mating. After that, breeding can be carried out, usually twice. Once, sows mate for the first time 12~24 hours after the boar climbs the hill (that is, presses the waist), and then mate again every 12 hours. It can also be used for estrus three times at a time, once every 12 hour, 14 hour and 12 ~ 14 hour after the boar climbs the hill. Let the sperm wait for the egg to arrive. The reason is that according to the study of ovulation law of Beijing black pig sow, the number of ovulation of estrus sow accounts for 65438 0.59% of the total number of ovulation within 0 ~ 24 hours after receiving boar crawling; Ovulation in 24 ~ 36 hours accounts for17.38% of the total ovulation; 36 ~ 48 hours is the peak of ovulation, and the number of ovulation in this period is as high as 65.57% (some people think that the peak of ovulation is 365,438+0 hours after the beginning of estrus, ranging from 25.5 to 36.5 hours). After 48 hours, the ovulation rate was still as high as 13.9%. Egg fertilization requires mating or insemination before ovulation, especially about 2-3 hours before ovulation peak, so that sperm can reach the fertilization site in the upper fallopian tube 1/3 in advance. Because sperm can live for up to 42 hours in sow reproductive tract, but sperm can only be fertilized for 25~30 hours. However, it takes much longer for an egg to have the ability to fertilize (8~ 10 hour, up to 15 hour). Therefore, it is necessary to mate or inseminate sows before ovulation, especially a few hours before ovulation peak, that is, 2-3 hours before ovulation, that is, it is necessary to start mating after the sow has the desire to mate and accepts climbing 12-24 hours, and mate again every 12 hours, so that sperm can wait for the arrival of eggs. However, due to the different ovulation times of different breeds, different ages and different individuals, it is necessary to be flexible in determining the mating time.
In terms of breeds, local pig breeds have longer estrus duration and later ovulation, so they can be bred on the third to fourth day of estrus; The varieties introduced from abroad have short estrus duration (sometimes the estrus symptoms are not obvious, and the estrus start time is difficult to control), ovulation is early, and mating can be carried out the next day; The hybridization between local pig breeds and foreign pig breeds can be carried out in the afternoon of the second or third day after estrus.
Secondly, from the age point of view, the estrus time of young sows introduced with pig breeds is shorter than that of old sows, while the estrus time of young sows is longer than that of old sows in local breeds in China. Therefore, for the local varieties in China, it is necessary to have the experience of "old matching early, small matching late, not old and not many matching middle". In other words, the old sow's love lasts for a short time, and it will be arranged once that afternoon and once every 8- 12. Sows have a long estrus cycle and generally breed on the third day; Middle-aged sows breed the next day.
If the estrus is very short, you can breed after mating (press your waist with your hand and the sow stands still); Every 12 hours 1 time. Or mating for the first time 8~ 12 hours after mating; Do it after 8~ 12 hours. If offspring are used as fat pigs, it is better to use two boars, which can not only improve the conception rate and litter size, but also improve the viability of piglets.
So, we can
① Repeated mating: the same boar is mated or inseminated every 8~ 12 hours after estrus begins, and mated again every 12~ 18 hours.
② Double mating: In one estrus, two boars (boars of the same breed or different breeds, but this method cannot be used in breeding farms) are mated once every 5 ~ 10 minutes. Mixed semen can also be used for insemination.
③ Multiple breeding: generally three times.
4. Find out the reasons of sow's lack of emotion and take corresponding measures:
Reasons why sows are not in estrus:
(1) is older;
(2) The summer climate is too hot (the estrus rate of adult sows weaned from July to September is higher than that of other months, especially the young sows born at first birth, and these sows can estrus for more than 120 days);
③ insufficient light in pigsty or daily light exceeding 12 hours can inhibit estrus activity;
④ Fatness and nutrition of sows are poor (soybean meal, corn and green feed can be added); Or the sow is too fat (for obese sows, it is necessary to strengthen exercise, reduce feed, or even stop feeding and water for one day to promote estrus);
⑤ Reproductive organ diseases: such as ovarian cyst, endometritis, persistent corpus luteum (intramuscular injection of 0.2ml of cloprostenol), etc. Other diseases: such as rickets, myopathy, claudication, etc. Old sows that are difficult to cure and have low fertility should be eliminated in time.
⑥ Endocrine disorder. Sows suffering from endocrine disorders but not in estrus can adopt:
(1) induced estrus:
1. boar induction method: boars and sows are in continuous contact to stimulate their sexual desire; Play the recording tape of boar courtship, and then try it for a few days;
2. Social method: Put the oestrus sow in the oestrus sow pen, and stimulate oestrus through the crawling of oestrus sow;
3. Breast massage method: Massage the surface layer of each breast with your palm every morning after feeding 10 minute, and then massage the surface layer and deep layer for 5 minutes every day within a few days after the sow has oestrus symptoms (that is, put the tip on the skin around the breast without touching the nipple, do garden exercises, and massage the breast layer of the breast). Deep massage on the day of breeding 10 minute. The function of surface massage is to strengthen the function of anterior pituitary, make follicles mature and promote estrus. Deep massage is to strengthen the stimulation of pituitary gland, promote the secretion of follicle stimulating hormone, promote the synthesis of estrogen in follicles, stimulate sow estrus and increase the number of ovulation.
4. Nest-closing method: After eating colostrum for three days, all piglets born to sows with low litter size and poor lactation performance are fostered and fed to other sows with low litter size, so that sows with low litter size can return milk in advance and mate in estrus in advance, thus improving the annual litter size and litter size.
(2) Artificial aphrodisiac:
1. Feed sows 20~40mg of a new progesterone substance, called allyl decanonone (RU-2267) every day. Feed it for *** 18 days, and it will appear in 4~6 days. It is very effective, but the price is relatively expensive. Suitable for intensive pig farms.
2. Use hormones for aphrodisiac:
① After intramuscular injection of a mixture of vitamin A, vitamin D and vitamin E of 5 ~ 7ml/ head, on the third day, intramuscular injection of pregnant horse serum gonadotropin (PMSG) or PMSG-C 1000IU/ head (PMSG should not be excessive. Otherwise it will cause ovarian cysts). After intramuscular injection of HCG 500 ~ 1000 IU/ head on the sixth day, the estrus induction rate can reach 100%, and the estrus pregnancy rate is about 75%.
② Single injection 1000IU pregnant horse serum gonadotropin; Someone injected 500 international units of hCG (chorionic gonadotropin) into the muscle after long-term estrus.
Attachment: Preparation of pregnant mare serum: put 4g of borax, 2g of sodium sulfite and distilled water 12ml into a sterilization flask, steam sterilize for 20min after dissolution, take it out and cool it to 370C, then take the jugular vein blood 180 ~ 200ml of a healthy mare who is pregnant for 2 ~ 3 months, directly inject it into the bottle, then plug the bottle mouth and immediately oscillate 65438. It's on the market now.
③ Implanting 500mg of nortestosterone subcutaneously for 20 days, or injecting 30mg daily for 65,438+08 days, the pregnancy rate can reach over 80%, and the pregnancy rate can reach 60-70% after drug withdrawal.
④ Inject the same hormone into 1 sow once, dissolve it with 5ml diluent, and then inject it into the muscle behind the pig's ear and subcutaneously;
⑤ Inject pituitrin and chorionic gonadotropin (hCG).
If the above methods are ineffective, the Tao will destroy the principle.
Five. Strengthen measures to protect the fetus. Sows are prone to miscarriage 9 days after mating-13 days, and 2 1 day before delivery. In particular, we should strengthen measures to protect the fetus, try to supply protein, minerals, vitamins and other rich concentrate and green juicy feed, and avoid feeding frozen, moldy and deteriorated feed. Pregnant sows try to avoid mechanical stimulation, such as squeezing, biting, slipping, whipping and scaring.
Six. Pig raising should be recorded in detail to avoid inbreeding.
7. Early weaning to increase the number of babies per year.
Weaning in an average of 28-30 days can ensure that a sow can produce 2 or 2.5 litters a year. Most sows after early weaning can estrus for 5-7 days, and the pregnancy rate is between 90% and 95%. Generally speaking, sows are fed aphrodisiac 3 -5 days after weaning. After the sow is in estrus, it can be bred during lactation, and it can also increase the annual fetal yield.
8. Eliminate the update and optimize the pig structure.
Old, weak, sick, disabled and low-yield sows should be eliminated and updated in time. Generally, the annual elimination rate of sows is 25%~30%, so it is necessary to replenish reserve sows in time to ensure a reasonable proportion of sows in the pig herd: 20% old sows, 60% middle sows and 20% young sows.
Nine. Strengthen epidemic prevention and drug health care to reduce the occurrence of diseases affecting reproduction.
There are several diseases that plague and cause sow abortion, premature birth, stillbirth and weak birth, which should be strictly guarded against:
Especially the prevention of Japanese encephalitis, influenza, brucellosis, parvovirus, pseudorabies and other diseases, and timely treatment when diseases are found. Those with threatened abortion should be injected with progesterone 15 mg -25 mg immediately, and the fetus should be induced by oral sedative.
Porcine parvovirus causes stillbirth, abortion and mummification. 2ml porcine parvovirus vaccine was injected into sow muscle 2 ~ 3 weeks before breeding. Immunize it before breeding. Boars were immunized for the first time at the age of 8 months, and then injected with/kloc-0 and/kloc-0 2ml every year.
Pseudorabies causes stillbirth, mummification, abortion and weak birth. The ratio of suckling pig 1 is 0.5ml for injection after weaning 1 ml; Middle-aged pigs over 3 months old1ml; Adult pigs are injected 1 time every year, and 2ml boars can also be injected once a year in spring and autumn, 1 head/head; Four weeks to five weeks (30 days) before mating, the reserve sow is inoculated 1, and the pregnant sow is inoculated 1 30 days before delivery. The immune period is 1 year.
Classical swine fever can cause abortion of pregnant sows, edema of aborted fetus, epidermal bleeding and so on. Prevention is mainly to make vaccines, and choose high-quality attenuated rabbit vaccine for inoculation. 30 days before mating, 2 doses (3 doses of cell seedlings/head) were injected to the sow at weaning, twice a year. You can also vaccinate the spleen of boars, sows and reserve pigs three times a year, and the first dose is intramuscular injection, which is implemented across the board.
Respiratory and reproductive system syndrome caused by blue ear disease. One size fits all: male, female and reserve pigs are inoculated three times a year, 1 head/head (Boehringer) or according to the instructions (domestic seedlings).
Japanese encephalitis mostly occurs in autumn, or young sows with one or two births, and is mainly spread by mosquito bites. Therefore, JE vaccine is injected every year before the arrival of mosquitoes, and the first dose is injected subcutaneously or intramuscularly in April-May.
For physical injuries caused by heatstroke, poisoning and other reasons, preventive and health care drugs should be taken at ordinary times.
Choose some broad-spectrum, long-acting and targeted drugs. such as
Antibacterials: florfenicol, sulfahexamethoxazole, tetracyclines (tetracycline, oxytetracycline, doxycycline, chlortetracycline).
Antiviral drugs: Ribavirin, Astragalus polysaccharide, Radix Isatidis.
Antigen pesticides: triazolam, diphenhydramine, trimethoprim (TMP).
Immunomodulator: Astragalus polysaccharide, electrolytic multivitamin.
Nutritional supplements: oral rehydration salts, various amino acids, etc.