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Managing Lawsonia intracellularis infections in a large production system in the USA

by 5m Editor
31 October 2005, at 12:00am

By Dr Andrew John Holtcamp, Iowa Select Farms - Our production system raises approximately 2.5 million pigs per year, out of a total US production of 100 million pigs. Production facilities are typical for the Midwestern U.S. We have an average sow farm size of 4,000 sows, with approximately 1,500 new gilts per farm per year. Nursery and finishers are housed separately off site (multi-site production).

Boehringer Ingelheim

Introduction

Most finishing barns have deep pig manure storage over slatted floors, though 20% are shallow pits with “pull plug” systems. In this large a production system, health controls, like any management programs, must be standardized, simple and repeatable to apply, and deliver consistent results, with little added treatments needed.

Situation before vaccination


Figure 2.1: Influence of vaccination with Enterisol® Ileitis on use of Feed-Grade Tylan®
The history of enteric disease in our pigs included all common pathogens seen in commercial pig production – feed induced diarrhoea, gastric ulcers, Salmonellosis, PCV-2, non-specific colitis, hemorrhagic bowel syndrome, torsions and endemic TGE (transmissible gastroenteritis virus). These conditions were diagnosed by routine pathology and histopathology. Both the chronic/PIA form and acute/PHE forms are present in the system. Chronic diarrhoea historically began in commercial pigs from 70 kg/150 lb to market, in the finishing barn. Hemorrhagic ileitis would occur in some groups of pigs around the first marketing cut, and in replacement gilts after placement into sow farms, at around 33 weeks of age.

Control of Lawsonia intracellularis and other enteric diseases was attempted with feed grade medications. In nursery pigs, a system of carbadox, tiamulin/chlortetracycline and chlortetracycline alone was used. This continues today for its broad spectrum respiratory and enteric benefit. Control of Lawsonia intracellularis in finishing was based on several combinations of tylosin, either at 100 ppm followed by 40 ppm, or 40 ppm continuously from 35 to 60 kg. Breaks on this medication program occurred frequently, at an average of 70 or more enteric cases per month. Water soluble tylosin was used as the first treatment option. When cases would not respond, water therapy was changed to tiamulin.

Situation after vaccination


Figure 2.2: Treatments for Ileitis-like disease pre- and post-vaccination
The goal for use of Enterisol® Ileitis FF was to reduce overall in-feed and water medication use, and, with similar cost, improve clinical control of disease in both high value replacement gilts and finishing pigs. Replacement gilts were the first target for vaccination given their cost and the poor response to treatment of PHE cases. Vaccination of these animals began in 2001. Following success in these animals, vaccine was tested in finishing pigs in 2002, with pigs vaccinated at 12 – 14 weeks of age, just following placement into finishing.

To manage the deep frozen vaccine, ultra-low freezers were purchased to allow for better quality control and insure the potency of vaccine. A dedicated administration team both measures water intake the day prior to vaccination and gives vaccine the following day. This format gave better results than multiple farm managers trying to apply vaccine themselves, as indicated by fewer treatments following vaccination done by dedicated field personnel.

These breaks could be tracked back to improper storage or thawing of the deep frozen vaccine, use of chlorinated water for stock solution, or inadequate vaccination time due to excess consumption of water. When properly handled and administered, diarrhoea breaks in vaccinated pigs or gilts are rare.

Vaccination has dramatically altered the feed medication program in finishing pigs and replacement gilts. Routine use of both in-feed tylosin as well as growth promoting antibiotics has dropped to zero. The numbers of groups needing treatment for diarrhoea of any kind has been reduced over 75% (<15 cases/month now) even with the removal of all in-feed medications. This has made health management much simpler at the field supervisor level, as well as in the feed mill.

Conclusions

The clinical response to vaccination drove the decision to apply vaccine in all pigs in our system nearly three years ago. We continue to vaccinate all production animals today with a consistent benefit and ability to feed our finishing pigs with-out growth promoters or therapeutics in feed.

Source: Boehringer Ingelheim - October 2005