Serological investigation report on sow reproductive disorders

Serological investigation report on sow reproductive disorders

Abstract: With the increasing scale and intensification of pig farms, the types of swine diseases are also increasing. Especially in recent years, sow reproductive disorders seriously restrict the development of the hog industry. In 2004, we introduced a foreign pig-type double sow with an external bloodline and carried out the promotion of excellent varieties. As a result, 80% of the pigs in the farms generally had miscarriage, premature birth, stillbirth, newborn piglets and weaned piglets. The rate and mortality rate increased by as much as 20%, while the sows generally did not have symptoms of Linqing. In this case, we are condensed as a sow reproductive disorder, so a serum survey was conducted. A total of 237 blood samples were taken, 212 serum samples were separated, and all the 212 serum samples were tested for blue ear disease, of which 80 were positive and the positive rate was 37.7%. 160 of the serums were tested for pseudorabies, 160 A swine fever test was performed and 160 sera were tested for parvovirus. The results showed that more than one sow reproductive disease existed in more than one farm. It can be seen that sow reproductive disorder is widespread in pig farms outside our county.
Keywords: sow; reproduction and respiratory syndrome; investigation; serology; detection
As hog farms have increased in both size and efficiency, so have hog disease types, In rencent yesrs, the problem has been especially serious among breeding sows, where disease has increased inferticity and negatively affected the development of the hog breeding industry In 2004,blood Was collected from 237 sous From these,212 samples of serum were successfully produced and tested for bluc Ear pisease .The positive test rate Was 37.7 percent Also tests for three types of disease porcine pseuudo rabies,swine Fever,and wicroscopic Viral infection were performed, Each test on 160 of the samples.
Sow;porcine reproductive and respiratory
Sow reproductive disease is a major disease that has plagued sows in recent years. It has been widely recognized by people. It has miscarriage, stillbirth, mummified fetus, weak abortion, deformed fetus and sow in pregnant sows. It is a type of disease that is mainly characterized by breeding and breeding. The disease mainly includes swine fever, pseudorabies, porcine parvovirus disease, reproductive and respiratory syndrome and porcine encephalitis. In 2004, we collected blood from 237 sows in 13 pig farms with obvious reproductive disorders, separated 212 serum samples, and tested all the 212 serum samples. 160 of them were pig pseudo-pseudo. The detection of rabies and porcine parvovirus, and the reasons for the reproductive failure of sows were analyzed and summarized according to the test results. The details are as follows.
1 Materials and methods
1.1 Materials
1.1.1 The serum to be tested is taken from 13 sow farms, blood is collected from the ear vein, and serum is separated at 3600 rpm for examination.
1.1.2 Main diagnostic reagent Blue ear ELISA kit: provided by American IDEXX company;
Porcine sputum diagnostic antigen and negative and positive serum: provided by Lanzhou Veterinary Research Institute;
Pig pseudorabies LAT diagnostic solution kit: provided by Huazhong Agricultural University;
Porcine Parvovirus LAT Diagnostic Solution Kit: Provided by Huazhong Agricultural University.
1.2 Methods
1.2.1 Sow breeding in respiratory syndrome method: indirect ELISA
A sampling: routine blood collection, separation of serum, no spoilage, hemolysis, clots and sedimentation.
B preparation:
Before the test, all the reagents were taken out from the freezer, set to room temperature at room temperature, and gently shaken, and then put back into the freezer immediately after use.
B The bath solution which reached room temperature and was completely dissolved was diluted 10 times with sterilized water or deionized water.
C The test serum was diluted 40-fold with the dilution; note that the positive/negative control serum was diluted in a hurry.
C. Remove the 96-well plate of the antigen spore and mark the position of the sample on the worksheet.
D Take 100UL negative serum and add to the C1, C2, D1, and D2 wells.
E 100 ng positive serum was added to the wells A1, A2, B1, and B2, respectively.
F 100 ul diluted test sera were added to adjacent PRRS antigen wells and MARC-145 cell antigen wells.
H was incubated at room temperature for 30 mim.
L Pour the liquid in the well of the reaction plate into the waste liquid tank and buckle it on the absorbent paper.
J Add 300UL washing solution per well, set the room temperature to about 3mim, discard the liquid in the well, repeat 3-5 times, and finally gently dry the water in the absorbent paper.
K was added to the 100 UL enzyme-labeled antibody complex per well and incubated at room temperature for 30 mim. And using this gap, take an equal amount of substrate concentrate and substrate dilution to mix.
L repeats I and J operations.
M was added 100 μL of the diluted substrate solution per well and incubated at room temperature for 15 mim.
N added 100 stop solution per well
O The absorbance values ​​of each well were measured by an enzyme-linked immunosorbent assay at a wavelength of 650 NM.
Q result judgment:
a pc:PRRS-NC: PRRS≥0.150, the test party is established.
b S/P ≥ 0.4, the sample serum PRRS antibody is positive; S / P < 0.4, the sample serum PRRS antibody is negative.
1.2.2 Detection method of swine fever: forward hemagglutination test
a Take a clean glass slide, crayon into 3 - 4cm2 small cells, as shown below, the serum number, the first grid, the second grid, the third grid, the fourth grid, the positive serum control, 0.08ml, 0.04ml, 0.02ml, 0.01ml.
Negative serum control 0.08ml 0.04ml 0.02ml 0.01ml
Serum sample 1 0.08ml 0.04ml 0.02ml 0.01ml
Serum sample 2 0.08ml 0.04ml 0.02ml 0.01ml
b Before the test, the serum to be tested, standard serum and antigen were placed at room temperature to reach 20 °C.
B. The serum to be tested and the standard serum are added to the respective cells according to the amounts in the above table.
C Shake the antigen and add 0.03 ml of antigen vertically to each serum compartment.
Starting from the 0.01 ml serum grid, the antigen and serum were thoroughly mixed with a toothpick, and the diameter was about 2 cm, which was sequentially adjusted to 0.02 ml, 0.04 ml, and 0.08 m serum. One serum sample was used for a toothpick.
E After gently shaking the slide, let stand for 5-8 minutes at room temperature. When the room temperature is low in spring and winter, it can be placed in an incubator at around 30 °C.
F records showed large agglomerates or small particles, and the liquid was completely transparent, that is, 100% agglutination.
There are clear agglomerates and granules, and the liquid is almost completely transparent, ie 75% agglutination.
There are visible agglomerates and particles, and the liquid is not transparent, ie 50% agglutination.
1.2.3 Detection method of pig pseudo-rabies: Latex agglutination test operation procedure Take one drop of each sample to be tested, positive/negative control serum and diluent, place on slide, add one drop of latex antigen, stir with toothpick or matchstick, and After gently shaking for 1-2 min, the results were observed within 3-5 min.
Serum can also be serially diluted in serial dilutions, and each dilution plus latex antigen for quantitative analysis.
C judgment result:
All the controls were established, that is, the positive serum was "", the negative serum and the diluent were "-", and the test was effective. Samples with a "++" or higher are positive.
1.2.4 Detection method of porcine parvovirus: latex agglutination test.
2 Survey content
2.1 Epidemiological survey: Through survey records, investigate the source of the seed, the parity, and the seasonality of the disease.
2.2 Feeding management survey: mainly includes feed quality, nutrient composition, whether there is enzyme change; whether there are environmental, mechanical and other adverse factors, whether the epidemic prevention, immunization and disinfection are in place.
2.3 Clinical case dissection: including clinical examination of breeding sows and pathological observation of some weak and newborn piglets produced in sick sows.
2.4 Serological test: The serum samples of 212 collected were tested for blue ear disease antibody and some serum were detected by pseudorabies, swine fever and porcine parvovirus.
2 Test results and discussion
3.1 The sows with reproductive disorders have Changbai, York and Changbaiyu York. There is no obvious strain difference in the sick sows; the births are mainly concentrated in the first child. After the first child, many sows no longer show obvious. Reproductive disorders; the disease is not seasonal, can occur all year round; the affected pigs mainly show the death of stillbirth, mummified, weak and newborn piglets.
3.2 The feed of the farm is basically fed to the special materials for the sow. There are no enzymatic changes and quality problems, and there are no abortions and stillbirths caused by environmental or mechanical factors. In the blood test, except for the two pig farms, which can not produce strict immunization records, other farms are immunized according to the immunization program and disinfected regularly.
3.3 Dissection of weak and newborn piglets, the general performance is consistent, the surface anemia is pale, the subcutaneous fat is more yellow, the kidney is yellowish, there are small bleeding spots on the surface, some lymph nodes edema and hemorrhage are marble-like, pericardial effusion , lobular pneumonia, liver brown yellow.
3.4 Serological test results:
Sow reproductive disorders disease serological test statistics table pig farm blue ear disease pseudorabies parvovirus reproductive disease history number of samples positive number positive rate sample number positive number positive rate sample number positive number positive rate
1 field 35 10 28.6% 14 8 57.1% 14 6 42.9% 11 abortions, stillbirths, mummies
2 games 32 7 21.9% 17 10 58.8% 17 8 47.1% Unknown
3 games 14 5 35.7% 14 10 71.4% 14 9 64.3% 14 abortions, stillbirths, mummies
4 games 20 14 70.0% 20 14 70.0% 20 16 80.0% 4 hair abortion
5 games 26 13 50.0% 13 11 84.6% 13 9 69.2% Unknown
6 games 13 2 15.4% 13 6 46.2% 13 7 53.8% 9 abortions, stillbirths, weak babies, mummies,
7 games 9 1 11.1% 9 6 66.7% 9 5 55.6% 1 with no seed, 1 stillbirth, 7 abortions, weak
8 games 11 0 0.0% 11 8 72.7% 11 8 72.7% 11 abortions, stillbirths, mummies, weak
9 games 12 7 58.3% 12 6 50.0% 12 7 58.3% 12 abortions, stillbirths, weak babies, mummies
10 games 7 2 28.6% 7 6 85.7% 7 4 57.1% 7 stillbirths, mummies
11 games 7 3 42.9% 4 2 50.0% 4 3 75.0% 7 miscarriage, stillbirth, mummy
12 games 24 16 66.7% 24 20 83.3% 24 17 70.8% 24 miscarriages, stillbirths, weak babies
13 games 2 0 0.0% 2 2 100.0% 2 1 50.0% Two pigs with a total of 212 80 37.7% 160 109 68.1% 160 100 62.5% 110 reproductive disorders
4 Summary and analysis
4.1 Through epidemiological, feed, feeding management and necropsy of weak and newborn piglets, the possibility of sow reproductive disorders due to variety, source, feed and feeding management factors is ruled out. Because the necropsy has a certain pathological change, it is caused by pathogenic factors such as viruses or pathogenic microorganisms.
4.2 The monitoring and sampling are all carried out by professionals. The blue ear disease detection adopts the US imported ELISA reagent, the microcomputer numerical control machine washes the plate, the pseudorabies and parvovirus adopt the LAT kit of Huazhong Agricultural University, which has high sensitivity and reliable monitoring results.
4.3 Monitoring pigs were not vaccinated against blue ear vaccine, and were immunized with pig pseudorabies and porcine parvovirus vaccine. The monitored pig population was positive for blue ear disease, indicating that there was infected pig or had been infected; pseudorabies, parvovirus immunization The pass rate reached 68.1% and 72.5% respectively, indicating that the immune effect of the breeding pig is better.
4.4 The sample of this monitoring is large, the test results are representative, and the monitoring results are 37.7% positive for blue ear disease samples, among which 1 to 5 samples have a positive rate of 38.58%, and the positive rate of blue ear disease samples in pig farms is relatively high; pseudorabies The immunopositive rate of parvovirus is relatively high, indicating that the breeding pig has a higher resistance to the disease after immunization or infection, and is protected from virulent attacks.
4.5 In this investigation, it was also found that the same pig was negative in blue ear disease, and the immune rabies and parvovirus immune antibodies all reached immune protection. There were still reproductive disorders, indicating the breeding disease in the farm. Not only caused by blue ear disease, pseudorabies, parvovirus, but also other reproductive disorders.
5 Prevention and control suggesting reproductive disorders, especially blue ear disease, it is the first new disease detected in our county. It is a serious hazard to the pig industry. First, it causes serious breeding and breeding disorders, leading to other diseases. Immunosuppression, which produces immune failure; second, it is difficult to control and eliminate recessive swine fever, and is a potential killer of sow reproductive disorders; third, pig pseudorabies and porcine parvovirus can not accurately determine whether it is a decisive disease after immunization factor. In the face of current reproductive disorders, the first is to strengthen the immune system of blue ear disease, to control the further spread of virulence in the group; the second is to further strengthen the immunity of piglets, pig pseudorabies, pig parvovirus, and improve the immunization rate of pigs. , so that the three diseases lead to miscarriage, stillbirth, etc.; the third is to strictly introduce the introduction, to avoid the adjustment of pigs in the blue ear disease epidemic area, the introduction must be negative after blue ear disease detection; the fourth is to further Accurate monitoring and diagnosis of several reproductive diseases, and increase the monitoring surface, eliminate the purification of positive pigs, and keep the farm clean.
references
1. "New results of research on prevention and treatment of important infectious diseases in pigs";
2. Basic Veterinary Medicine;
3. "Basic knowledge of operational skills of animal laboratories";