IT goes without saying that the major focus of the swine industry since last summer has been porcine epidemic diarrhea virus (PEDV).
No doubt, the brutal impact of this virus has been felt nationwide, especially within sow herds where young pigs and those who are charged with caring for them are often overwhelmed.
The effect of this disease has created a scenario where we'll likely see the highest market prices ever for finished pigs this summer — a reality that all producers would like to take part in with as many pigs available to market as possible at that time.
Within finishing pigs, those of us who have dealt with PEDV would say that other than a period of severe diarrhea and reduced weight gains, the greater challenge has been to prevent tracking the virus onto additional sites and ensuring barn sanitation in preparation for new pigs.
With all of the attention paid to PEDV, other finishing enteric diseases that often have an even greater impact on producers' bottom line can, unfortunately, be missed. Ileitis and swine dysentery, both of which are treatable and preventable causes of finishing diarrhea, shouldn't be overlooked.
The following "case studies" are two examples.
The caretaker of a 2,400-head, feeder-to-finish site calls to explain that three healthy pigs were found dead the prior day and that another four were found that morning. The pigs are approximately 200 lb. and have had very few health challenges to date.
During the veterinary visit that afternoon, while walking pens, individual pigs are quickly noticed that have runny, dark-red diarrhea. In addition, several other pigs are smeared with manure of the same color and consistency.
While discussing these pigs, the caretaker indicates that this issue just recently began — at about the same time that the first mortalities occurred.
The four pigs found during the morning chores are all outside. All had been in good body condition, and each seems paler in appearance than anticipated. No other external lesions are found.
A postmortem examination reveals the following in all pigs:
* Lungs are visually normal, with minor lymph node enlargement.
* No gastric ulcers are detected; in fact, two out of four have feed in their stomach still.
* There is a severe thickening of a lower portion of the small intestine that, once incised, reveals dark, almost bloody intestinal contents and a gritty material that has adhered to the intestinal surface.
* No other lesions are observed.
Based on the history and postmortem examination, a diagnosis of ileitis is made. To be certain, samples are collected from two pigs to confirm the diagnosis and rule out any additional pathogens.
As the diagnosis and treatment plan are being discussed, it was recalled that these pigs should have been vaccinated for ileitis shortly after arrival to the finisher. When the vaccination and treatment log for the barn are further investigated, it shows that the pigs were treated with an oral antibiotic the day after vaccination, which reduced the efficacy of the vaccine.
Before leaving, an antibiotic treatment plan is started that includes the administration of an oral, water-soluble antibiotic targeting Lawsonia intracellularis, the bacterium that causes ileitis. In addition, a plan is implemented to inject all pigs that are showing any signs of diarrhea, pallor or a gaunt appearance.
In a follow-up, it is learned that two additional pigs were lost the following day, with no additional mortality after the treatment plan started. Samples submitted confirmed ileitis.
A client who owns and operates several wean-to-finish barns has called to discuss a few of these sites.
She explains that over the last six to eight months, within one of the purchased flows, pigs routinely develop a moderate to severe scour a month into finishing. Pigs are single-sourced into sites and have seemingly good respiratory health from weaning to finishing.
Although the diarrhea is certainly a cause for concern, on the owner's mind that day is that this flow produces closeouts that are the worst in all of her operations, with poor feed conversion, low average daily gain and a reduced number to her primary market.
It is decided that a visit to multiple sites is necessary to observe these clinical signs, complete postmortem examinations and collect samples for an initial diagnosis.
In barns where active diarrhea is present, multiple pigs are gaunt, and a significant separation in size is apparent. In these sites, stools vary in consistency from watery to semi-solid and in color from gray to many that have a reddish tinge. Some of the diarrhea also contains clumps of mucous.
Postmortem examination of multiple affected pigs shows that all have visually normal lungs, with no signs of systemic bacterial infection. The small intestines are normal, and pigs that had diarrhea do not have gastric ulcers.
Moving further down to the colon, multiple pigs have signs of colitis, including reddened tissue surfaces, edema and thickened areas of the inner colon wall. In some pigs, the manure present in the colon contains flecks of blood.
Based on clinical signs, a preliminary diagnosis of swine dysentery is made, and samples are collected to confirm this. A treatment program is initiated that includes oral antibiotics in the barns where pigs are showing clinical signs. In addition, an antibiotic program for younger groups in this flow is put in place to prevent the onset of diarrhea when each of these pigs gets into its finishing phase.
A follow-up discussion with the veterinarian for the sow source reveals that this herd has had a number of diagnosed dysentery cases caused by the pathogenic bacteria Brachyspira hyodysenteriae. This bacterial agent historically had been isolated within the sow herd and is likely moving vertically with weaned pigs.
Looseness in finishing pigs' stools should always be considered abnormal, so when observed, further investigation is warranted. PEDV has certainly caused the lion's share of finishing diarrhea over the last nine months, although other causes are still frequently diagnosed in finishing pigs.
Ileitis and swine dysentery are two common diseases that negatively affect the profitability of swine producers, but both are treatable and preventable.
Complete diagnosis requires submitting samples to a veterinary diagnostic laboratory, but a lot can be learned from postmortem examinations, which allow for a preliminary diagnosis and same-day implementation of a treatment.
Reductions in feed efficiency and average daily gain have always been costly. Mortality this summer and fall will carry with it an even larger price tag. Swine producers should make sure they don't let finishing diarrhea cause them to miss out on upcoming opportunities.
*Dr. Brad Leuwerke is with the Swine Vet Center in St. Peter, Minn.