Optimal vaccination strategy against Mycoplasma hyopneumoniae, porcine reproductive and respiratory syndrome virus, and porcine circovirus type 2 in case of early M. hyopneumoniae infection.

BACKGROUND: The aim of this study was to determine the optimal vaccination strategies for the control of porcine respiratory disease complex (PRDC) caused by Mycoplasma hyopneumoniae, porcine reproductive and respiratory syndrome virus (PRRSV), and porcine circovirus type 2 (PCV2) in case of early mycoplasmal infection. METHODS: A total of 120 pigs were randomly divided into 6 groups (20 pigs per group). Four separate vaccine regimen groups were selected. Pigs from the four vaccinated groups were challenged with M. hyopneumoniae at 28 days old followed by a challenge of PRRSV or PCV2 at 49 days old. RESULTS: Regardless of PRRSV or PCV2 vaccination, pigs vaccinated with one of the M. hyopneumoniae vaccines at 7 days old had a significantly better growth performance over the whole length of the study compared to pigs vaccinated with a second M. hyopneumoniae vaccine at 21 days old. Vaccination of pigs with M. hyopneumoniae at 7 days and PRRSV at either 7, 14 or 21 days old resulted in significantly reduced PRRSV viremia and lung lesions compared to vaccination of pigs with M. hyopneumoniae and PRRSV at 21 days old. CONCLUSIONS: The efficacy of the PRRSV MLV vaccine is influenced by the different timing of M. hyopneumoniae vaccination whereas the efficacy of the PCV2 vaccine is not. This experiment study demonstrated that early vaccination with a M. hyopneumoniae vaccine should be the highest priority in order to control M. hyopneumoniae and PRRSV infection in cases of early M. hyopneumoniae infection.

Current supply and demand of veterinarians in Japan.

Since 1966, approximately 1 000 veterinarians graduate each year from 16 veterinary schools in Japan. According to reports submitted by veterinarians to the Ministry of Agriculture, Forestry and Fisheries in January 2007, there were over 35 818 veterinarians in Japan at the end of 2006. Of this total, 13 202 (36.8%) were engaged in companion animal practice, 9 112 (25.4%) were civil servants and 4 180 (11.7%) were engaged in food animal practice. The total number of veterinarians has increased gradually over the past 40 years. Recently, the number of veterinarians engaged in companion animal practice has increased while the number of veterinarians engaged in food animal practice is declining. These trends reflect the change in demand for veterinarians in food and companion animal practice, resulting mainly from changes in the number of food animals and companion animals in recent years. The number of veterinarians in the public sector has decreased gradually due to the administrative reforms of recent years.