HUIZHONG NEWS

Luoyang Huizhong Biotechnology Co., Ltd. Environmental Prevention and Control Information Sheet for Hazardous Waste

2023-01-09

Preventive and Control Measures for Infectious Croup in Commercial Laying Hens During Spring

2022-04-14

The state will launch the third round of central frozen pork reserve procurement this year.

2022-03-15

Good News | Huizhong Bio’s Inactivated Rabies Vaccine (r3G Strain) Has Obtained the Veterinary Drug Product Approval Number from the Ministry of Agriculture and Rural Affairs of the People’s Republic of China.

2022-03-15

Five methods to help you choose chicks

2022-03-15

Analysis of a Pig Blue Ear Antibody Test Report from a Large-Scale Farm

Porcine reproductive and respiratory syndrome (PRRS) is a highly pathogenic infectious disease primarily caused by infection with the Porcine Reproductive and Respiratory Syndrome virus (PRRSV). Pigs of all ages, breeds, and sexes can be infected, but pregnant sows and one-month-old piglets are most susceptible. The main clinical signs include abortion in sows, stillbirths, weak piglets, mummified fetuses, and respiratory distress. This article uses the IDEXX PRRS antibody ELISA kit from the United States as an example to illustrate how to interpret PRRS antibody test reports. When analyzing these reports, particular attention should be paid to the following two aspects: 1. Antibody Positive Rate In the IDEXX PRRS antibody test kit, an S/P ratio less than 0.30 indicates a negative result, meaning no detectable PRRS antibodies or that antibody levels have not reached a protective threshold. An S/P ratio between 0.3 and 0.40 is considered suspect, placing the sample in a gray zone requiring retesting for confirmation. An S/P ratio of 0.4 to 2.5 is deemed positive, indicating the presence of PRRS antibodies at a protective level. If the S/P ratio is ≥2.5, although the result is classified as positive, based on experience with this kit, antibodies generated by routine vaccination typically do not reach such high levels. Therefore, extremely elevated antibody titers strongly suggest wild-type PRRSV infection, warranting additional testing for the virus and comprehensive clinical evaluation. 2. Coefficient of Variation (CV) The coefficient of variation (CV) is an important indicator of the uniformity of antibody levels within a pig population. Its magnitude reflects the consistency of antibody titers across the herd, enabling assessment of vaccination efficacy or infection status and providing valuable guidance for overall disease prevention and control. A CV ≤ 30% indicates stable antibody levels and good immunization effectiveness; a CV between 30% and 50% suggests moderate antibody uniformity; while a CV > 50% implies significant variability and poor uniformity among animals. 3. Case Study: Analysis of PRRS Antibody Test Reports Immunization Background A large-scale farm maintains a core breeding sow herd of 1,000 sows. Each year, sows receive four rounds of vaccinations against classical swine fever, porcine circovirus, PRRS, pseudorabies, and foot-and-mouth disease. In this instance, blood samples were collected from 40 sows—replacement gilts, and sows at 30, 60, and 90 days of gestation. PRRS Antibody Results for Submitted Samples Results Analysis Figure 1 shows the dispersion of PRRS antibody positivity rates across different stages of gestation. Figure 2 illustrates the distribution of S/P ratios for PRRS antibodies in the sampled pigs. As shown in Figure 1, the positive rates for PRRS antibodies across all four sampling stages are very high, nearly reaching 100%. However, the variability in antibody levels exceeds 50% in each stage, suggesting substantial differences in antibody titers throughout the herd and raising concerns about an overall unstable PRRS situation. Figure 2 further reveals that seven samples (17.5% of the total) have S/P ratios greater than 2.5, distributed across all stages of gestation. Taken together, Figures 1 and 2 indicate that the farm’s pig population currently exhibits an unstable PRRS status, likely representing an early phase of infection. It is recommended to promptly conduct pathogen testing for PRRS and, upon confirmation, implement urgent and scientifically sound preventive measures to safeguard herd health. Additionally, under current conditions, maintaining robust basic immunization programs is essential for ensuring stable production. While controlling PRRS, it is equally important to address another virus—porcine circovirus—that can induce immunosuppression in infected pigs. Porcine circovirus poses significant risks to pig herds and directly impacts farm profitability. To better protect pigs from circovirus infection and maintain stable production, we recommend using Huizhong Bio’s bivalent inactivated vaccine against porcine circovirus and classical swine fever. Featuring a water-based adjuvant, this single-dose formulation provides dual protection, saving time, effort, and costs.

2021-12-24