Dr. John Carr, an international livestock consultant, and a veterinarian had fought the war against PED virus since 1970 when it struck his farm as a 14-year-old in Yorkshire.

“But it is a war that we can win!”

Porcine Epidemic Diarrhea is a most dangerous acute pathogen of pigs. When it appears for the first time in the farrowing area, it causes such devastation it is beyond belief.

“None of the reports you have read describe the feeling of hopelessness. All the pigs below ten days of age die despite your best efforts. All of the sows are sick with vomit and diarrhea. The piles of dead pigs are soul wrenching,” said Dr. Carr. “Nursery and finishing units, however, are much less affected – a bad case of ileitis and we have all seen diarrhea before.”

He said sometimes this disconnect in clinical signs, can result in issues between different departments and even neighbouring farms.

“Grow/finishing guys apparently get over the problem quickly and with relief start farming again. But the scourge is still present but hidden in the background health issues. The farrow to weaning operations struggle along,” said Carr. “There is only one health status for PED control available, negative. Do not get lulled into a false sense of security reliant on vaccines.”

Carr who feeds pigs and consults with hog farmers all over the world said the farm with persistent PED is common in Asia where the problem occurs every 12-14 weeks on larger farms.

We see the problems predominantly in parity one sows (gilt litters) where many farms are unable to raise piglets from gilts until they eliminate the virus. But these farms can restore PED negative status with detailed applied biosecurity.

The farm must immunize gilts before they farrow to ensure they can provide sufficient protective colostrum to their piglets. Gilt litters can be supported by the provision of colostrum from parity 3+ sows to all parity one piglets during the elimination phase has worked on several farms.

It is unusual for the reinfection of the farm once they remove the virus. The outbreaks all stem from virus remaining on the farm or the farm strain reintroduced from gilts via the finishing unit for example. On a typical situation once the PED virus has gone through an area it does not appear to turn around.

Stabilizing the farm – paying for the PED outbreak

One immediate problem with the PED outbreak is the desire to pay for the hole it has created. There are suddenly vast numbers of sows available for breeding, and it is natural to want to breed these sows because they will produce piglets in the future.

But this can cause a tsunami of problems, with 17 weeks later too many sows farrowing, forced early weaning, overstocking in the nursery and grow/finish with all of the inevitable problems this creates. It is vital to work with your health team to create a plan. Do not over breed; stick to your pig flow target.

“Difficult, but my approach is to retrain the farrowing team to be able to wean an extra 0.5 piglet, over six months and this will replace the deficit,” said Dr. Carr about repaying the loss.

Cleaning is an essential part of ridding the facility of PEDv meaning eliminate the virus on the farm by cleaning and not providing naïve animals. The virus will then die out.

Dr. Carr said cleaning means cleaning absolute and resolute, totally because this is not a common pathogen. Drying is a critical control tool assisted by lime washing which allows the cleaning team to see where they applied the disinfectant. PEDv is easy to kill and using soap is more than enough, but again entirely and not miss any parts of the farm.

“The number one naïve animals are going to be piglets without colostrum or those that receive colostrum from poorly immunized animals, classically parity one sows,” said Carr. “During an outbreak do not add more gilts to the farm.”

Rearranging the batching program on farms can provide the farm with a significant advantage. Having no piglets for 2, 3, or four weeks can make breaking the cycle much easier. It is very unusual for a three week batching farm to have secondary PED virus outbreaks.

Putting the farm back together

The farm starts production, and it has the first piglets in the farrowing house, living and have not died! How pink they look. The smiles of joy and relief are palpable.

“But remember, you have only won half the battle. We need to keep them alive by maintaining the course of strict hygiene and disinfection. Do not be lulled into a false sense of security just because there are no clinical signs,” he said. “You may also have to learn again that piglet diarrhea isn’t all associated with PED. The use of the lateral flow devices, pig side tests can be a great boon at this point.

As part of the initial control program, it is advisable to separate the various teams on the farm, the breeding/gestation and farrowing team for example including coffee breaks. On many farms, we have even stopped guys shaking hands. Once the farm appears to start production, after a couple of more weeks the farm teams can start to work together: This is a real cause for celebration on the farm. •

— By Harry Siemens Pictures courtesy of Dr. Carr.