A36-Lancaster Farming, Saturday, April 8, 1995 PSEUDORABIES HEADLINE UPDATE A column to update hog producers on the Pennsylvania Pseudorabies Eradication Program. PSEUDORABIES SUCCESS STORIES Paul M. Pitcher, DVM, MS Assistant Professor Swine Health And Production Management University Of Pennsylvania School Of Veterinary Medicine New Bolton Center Those of us who are involved with pscudorabics are frequently impressed by the accomplish ments of quarantined swine pro ducers who are committed to cleaning up their herds. This arti cle documents such a case in a Lancaster County herd. Experience has shown that eli minating pseudorabies from large finish floors can be a very chal lenging task. The virus finds con ditions in such herds comfortable See the New “STRATFORD CLASSIC ” Coal Stoves at | DUSSINGER’S QU3LITY STOVES t - - . i 2533 Old Phila Pike, Rt 340, Smoketown, PA 3 miles east of Lancaster Tue., Thurs., & Frl. 10-8; Wed. & Sat. 10-5 * See our beautiful new Wood & Gas Stoves. ____ (717)397-7539 ■■■hbmmmhb AGRI-INC. Custom Built Farm Buildings Designed To Your Needs and very favorable to its survival. Large infected finish floors usually have many pigs which are actively shedding virus into the environ ment to infect any pig which has not yet been exposed. The large concentration of pigs in one facility means that it is not difficult for pseudorabies virus (and many other disease agents) to be transferred from pig to pig. Stress factors, such as dust, uneven temperature and ventilation, or crowding are often the cote of a problem in large herds and can make disease control difficult, par ticularly if die flow of pigs through the building is continuous. This case involves a large conti nuous flow finish floor of over 5,000-hcad capacity which was quarantined in 1992, after infected feeder pigs were moved to the facility from a quarantined breed ing herd. Pseudorabies became established at this finish floor. Later, uninfected pigs were sup plied by the breeding herd, but blood testing showed that all pigs wore being infected with pseudo rabies by the time they had been at the finish floor for four weeks. Pneumonia and poor growth rate were also problems at this facility, so in the fall of 1993, the decision was made to switch the flow of the facility from continu ous to all-in/all-out by room. That is. each of the nine rooms would be filled over a two-week period, pigs would remain in the same pens until ready for slaughter, and then the entire room would be emptied before it was refilled with young pigs. At the same time pig flow I through the facility was changed, vaccination of pigs for pseudora bies was initiated. Pigs received a single dose of pseudorabies vac cine at nine weeks of age, on the day they were moved from the nursery to the finish floor. Several groups of pigs were ear-tagged and blood-tested every 2 to 4 weeks to determine the patterns of infection in the herd. The first series of blood tests was done.three months after vacci nation was started and showed that only about 20 percent of pigs were responding well to the vaccine and that pigs were still becoming infected at around 13 weeks of age, even though they were vaccinated. These results were not surprising, as many pigs vaccinated for pseudorabies at such a young age do not respond well. So much virus was still circulat- 3 Point forklifts Wide selection of models Lift heights from S’ to 12’ Lift capacities from 3500# to 4400# Ideal for seed/fertilizer pallets Orchard crates All-around utility use Top quality construction - economically prices See Your Local Dealer For. More Irtformation or Contact: tgmSm\ CUMMINGS and \SZSJ BRICKER, Inc. 100-120 Lohlgh Avo P.O. Box 020 Batovla, Now York 14021-0021 716/343-5411 FAX 710/343-0346 ing that it was overwhelming any protection provided by the vac cine. Although the producer was discouraged, he realized that if vaccination was continued, there was a good chance that virus levels would gradually decrease, eventu ally allowing pigs to remain uninfected. Two months later, blood testing showed that vaccinated pigs were not becoming infected until 17 weeks of age, so progress was evi dent. By this time, all pigs in the facility had received a dose of vac cine. After two more months, another blood test was done. By this time, vaccine had been in use for seven months. This blood test showed that pigs were remaining uninfected all the way through market weight and age. However, some infected pigs were still on the premises, so a final blood test was planned. This final blood test, done nine months after pseudorabies vaccination was started, showed that pseudorabies had been com pletely eliminated from the facility. This case demonstrates that changes in pig flow and use of pseudorabies vaccine can produce rapid results, even in herds expected to be difficult to clean up. The transmission of virus from .infected pigs to uninfected pigs was completely interrupted some time between 3 and 4 months after vaccination was initiated. These 100 Stovor Drlvo Corlltlo, PA 17013 717/246-6720 FAX 717/240-0364 results were obtained without any disruptions to pig marketings or to work practices on the farm (other than the labor to inject vaccine). Apparently, the added separation between groups of pigs, combined with a reduction in virus shedding brought about by vaccine use, suc ceeded in stopping the spread of pseudorabies in this herd. The inci dence of disease symptoms also decreased. The neighboring swine produc ers are delighted that the pseudora bies threat imposed by this farm has been eliminated. We will be reporting in a later issue on changes in growth performance on this farm and others which have successfully eliminated pseudorabies.
Significant historical Pennsylvania newspapers