All animal drug and vaccine use is coming under more scrutiny these days. Whether the driver involves economics, food safety or animal welfare, the push is toward using less, not more.

The National Animal Health Monitoring System's Swine 2000 Study gives us a more detailed look at the pork industry's vaccine use. The results are tabulated based on three operation size categories: small = total inventory less than 1,999 hogs annually; medium = total inventory between 2,000 to 9,999 hogs a year; large = total inventory more than 10,000 hogs annually.

This article is the second in a series outlining NAHMS' survey results. For more details on how the study was conducted, check out the Sep-tember 2001 issue of Pork magazine.

Although the porcine reproductive and respiratory virus vaccine is not the most highly used vaccine, it tends to garner the most discussion. Overall, the study shows that 28 percent of all operation sites regularly administer PRRS vaccines.

The number of producers vaccinating for PRRS has declined since 1995. (See chart on page 23.) Veterinarian Eric Bush, NAHMS epidemiologist, points out that the first PRRS vaccine was introduced when NAHMS was conducting its Swine 1995 Study. He speculates the number of producers using some form of PRRS vaccine increased between that study and the Swine 2000 Study, but then tapered off.

This is especially true with the study's " large" farms. There's a siificant decline in PRRS vaccine use from 75 percent in the 1995 study to 32 percent in the 2000 study.

One reason for this decline stems from the 1998 pork market crash, says veterinarians Max Rodibaugh, Frankfort, Ind., and James Lehman, Columbia, Mo. For many producers, not using a PRRS vaccine was purely an economic decision. " Once some producers quit vaccinating for PRRS, and pigs didn't show clinical signs, owners proceeded without the vaccine," he says. Like any other disease, Lehman says a PRRS vaccine worked for some producers, but not all.

In addition, Rodibaugh contends that the pork industry seems to be moving toward eliminating PRRS, rather than just treating it.

I their experience, Rodi-baugh and Lehman say the PRRS vaccines may be more valuable for those producers utilizing mass vaccination protocols with or without breaks in pig flow. Overall, neither believes PRRS vaccine use will increase, especially as the industry is better able to control the disease.

In other findings:- Mycoplasma pneumonia was the most frequently used vaccine in sites with an inventory of 2,000 or more pigs marketed annually. About 60 percent of all producers use a Mycoplasma vaccine.

Rodibaugh didn't find this surprising. He points out there's a large population of susceptible pigs. " I expect to see Mycoplasma vaccines used more frequently. We need to get more producers running small operations to use them," he adds.

Lehman concurs that Mycoplasma is a significant grow/finish problem, even in large production systems using multiple sites. There is some speculation that some of the problems may be attributed to PRRS. " We've been using PRRS vaccines in some herds and still have respiratory problems," he says. " For some producers, it may be wiser to spend money on Mycoplasma and influenza vaccines. Of course, each operation is different."

  • Most producers vaccinate for both strains of the swine influenza virus, H1N1 and H2N3.
  • Producers with smaller units were more likely to vaccinate for erysipelas, Leptosirosis, parvovirus and rhinitis, while larger farms concentrate on Mycoplasma pneumonia and SIV.

There were a significant number of erysipelas outbreaks this summer in the Midwest. Rodibaugh notes the study indicates there's a significant decline in the use of this vaccine, which means there are a lot of susceptible pigs out there. " The reason is that we're separating pigs from the breeding herd and they aren't as likely to get exposure to the organisms, so pigs don't build up an immunity to some diseases," he says. " This is a trend we may see in other diseases as well." In the next five years, Lehman says if animal-health companies can come up with additional water-based vaccines, you'll see increased use. This trend is common in the poultry industry. These vaccines save time because you don't have to vaccinate individual pigs. Plus, they're easy to use and are a good food-safety tool in helping to prevent broken needles.

Vaccine use in the next few years may continue to decline if the industry is able to better control some of these more common diseases. And, a lot will depend on the strength of the hog market; a stronger market gives producers more incentive to use a preventative vaccination program. Seeking AdviceThe Swine 2000 Study asked pork producers if they consulted with a veterinarian before regularly using common vaccines. Overall, the study shows a slight increase in the number of producers consulting with a veterinarian ahead of vaccine use. Eric Bush, National Animal Health Management System epidemiologist, says declines in vaccine use reflected in the 2000 study involved sites that don't consult with veterinarians for vaccine use.

The drop in vaccine use could simply be an economic issue instead of a health decision, says Bush.

Producers running large farms tend to consult with a veterinarian before using a vaccine. Bush also notes that producers may have a vaccination program in place, and don't change it until advised differently.

" I recommend producers visit with a veterinarian before using any vaccines," says veterinarian Max Rodibaugh. " I would hope as veterinarians we could provide information to help producers make informed decisions about vaccine use." The following table reflects operations that consulted a veterinarian before using the following vaccines regularly
regardless of pig age.

Used Veterinarian for Vaccine Consultation
Type of Vaccinations - NAHMS 2000 Yes No
PRRS 40% 25%
Erysipelas 64% 43%
E. coli scours 51% 30%
Parvovirus 61% 41%
Leptospirosis 60% 44%
Swine influenza virus, H3N2 16% 6%
Swine influenza virus, H1N1 17% 8%
Rhinitis (Pasturella, Bordetella) 46% 30%
Mycoplasma pneumonia 52% 33%
Any other disease 29% 27%
Type of Vaccinations - NAHMS 1995 Yes No
PRRS 34% 28%
Erysipelas 79% 70%
E. coli scours 68% 52%
Parvovirus 74% 71%
Leptospirosis 79% 71%

Source:NAHMS 2000 and 1995 swine studies