Better Pork - April 2007

Cover Story

Combatting the scourge of PRRS

It’s long, costly and demoralizing to deal with. ‘The psychological bruising of the staff is huge. Some people vow never to do it again,’ says one farmer. But all three are working their way through the crisis

by KATE PROCTER

Porcine Reproductive and Respiratory Syndrome (PRRS) not only hits pork producers around the world with huge financial losses, it is also demoralizing and frustrating for staff and owners.

The OPIC Swine Health Advisory Board (OSHAB) has taken on a project to create a better understanding of PRRS in Ontario and the best ways to fight it. Six producers have agreed to take part in a study, in which they will open their books and their operations for the benefit of the industry. Better Pork will be following this group of producers as they struggle through the aftermath of PRRS outbreaks and discover what works and what doesn’t. In this issue, we introduce three of the six producers – Gerald and Donna Jantzi, Bill MacDougald and Martin and Teresa VanRaay.

Gerald and Donna Jantzi, owners of Gerdon Farms Inc. located near Millbank, are shareholders in Affinity Pork, which has a total of 15 shareholders and has been in operation since 2004. It includes two sow farms with 1,450 sows each, 11,000 nursery spaces on four locations and 20,000 finishing spaces on 10 locations. Affinity Pork shareholders own most of the sow, nursery and finishing farms, but the company owns the animals.

One of the sow units, Burnside Sow Unit, has been in operation since October 2000. On November 28, 2005, the barn had its first clinical symptoms of PRRS. The outbreak started with a single abortion and a reduction in sow feed consumption. There was also an increase in the rate of stillborn piglets and weak piglets at birth. About 10 to 12 days after the first abortion, there was a noticeable spike in the piglet death rate.

The Jantzis medicated the water with aspirin and baking soda on Dec. 1 to help fight the sows’ fevers and keep them feeling better, so they would continue to eat and feed their piglets. On Dec. 7, Gerald Jantzi says, they started to put Pulmotil in the feed and continued doing this for about two weeks, at a cost of $17 per sow. Pulmotil is a feed additive made by Elanco and is used as an aid in reducing the severity of respiratory diseases caused by several different organisms.

About three days after the Pulmotil went in the feed, the abortion rate went down. While the use of Pulmotil is not widespread in Ontario, Jantzi feels that the additive helped the herd get back to normal faster. By Dec. 17, they had had a total of 66 abortions.

On Dec. 2, the farrowing room staff implemented the McRebel procedure, a procedure that limits piglet fostering in an attempt to reduce the amount of virus circulating in the farrowing rooms. Any fostering is to be completed within the first 24 hours of birth and no piglets are to be fostered between farrowing rooms. Since fostering is one of the primary tools used to keep litters even and save piglets that fall behind, McRebel is hard to implement and frustrating for staff. In order to fight PRRS effectively, it is essential that all animals in the herd be exposed to the same virus. On Dec. 10, they harvested serum by drawing blood from the sows and piglets that had the highest levels of virus.

The serum can then be separated from other particles in the blood and added to a medium to create a vaccine on-farm that is then administered to all the animals. On Dec. 11, staff injected gestating sows with virus. The procedure was repeated on Dec. 14, when blood was taken from the most viremic piglets. The amount of virus present can vary greatly between piglets, so a sample is sent to the lab to determine how much serum is required to inject the herd. This serum was used to inject all the gilts in order to ensure that all the animals in the herd were exposed and not shedding virus when they joined the breeding herd.

By Dec. 18, things started looking better in the farrowing rooms. The quality of the newborn piglets was better, but PRRS was just beginning to make its presence felt further down the line. The first nursery received viremic piglets on Dec. 21 and they saw an increase in swollen joints and problems with strep suis.

When piglets were still viremic in the spring, Jantzi says they continued to reinforce the McRebel procedure until, finally, on June 15 the first PRRS-negative piglets left Burnside for the nursery, almost seven months after the disease first made its presence felt. But, just to be on the safe side, they continued with the procedure until August. Dealing with the disease was very depressing and demoralizing for the staff. There was a huge amount of extra work and, no matter what they did, the piglets still died or were of lower quality, says Jantzi. “We thought we’d be producing PRRS-negative piglets faster than we did,” he adds.

Surprise outbreak
Bill MacDougald owns and operates MacDougald Pork near Fullarton. He currently has a breeding herd of 1,350 from which he sells feeder pigs. He contracts nursery spaces and sells his animals after they grow through that stage.

Four years ago, MacDougald’s herd broke out with PRRS. He was able to eradicate the disease from his herd and began blood-testing every group that went out at seven to eight weeks.

MacDougald’s sow operation has good isolation from other barns in the area, so it was quite a surprise for him when this barn came down with PRRS again last November. His nursery barns are located in Logan and McKillop townships, both high-risk areas, but those barns were both running negative for PRRS. 

The sows’ feed consumption went down and many had elevated temperatures. It looked more like an influenza outbreak at first, said MacDougald. By the second week in November, some sows started aborting, but there was no impact in the farrowing rooms at that time. Then the piglets started to be affected. “They looked like PRRS pigs,” says MacDougald. He and his staff drew blood and got a positive test for PRRS.

The farrowing rooms experienced a couple of bad weeks, with mortality rates running at 20 per cent or more, but then recovered relatively quickly, says MacDougald. During the worst week, they had showed a pre-wean mortality of 33.7 per cent. In the farrowing rooms, he says, “there is nothing you can do. We spent so much time and effort trying to save them, but you just couldn’t.”

MacDougald and his staff also followed a strict McRebel procedure. They would foster piglets just for the first 24 to 36 hours of life, and a lot of sows went out of the farrowing rooms without having weaned any piglets. “By the end of the process, we had a very heavy cull,” he adds.

While trying to stay positive, MacDougald says that people have a tendency to go through a denial phase and tell themselves that it is not as bad as it looks. It is very hard on people who are in the business of saving pigs. One woman who worked in the nursery barn that got the worst piglets would phone in tears, blaming herself for what was happening. “The psychological bruising of the staff is huge. Some people vow never to do it again,” he says.

The reproductive performance of the sows was affected and the herd experienced elevated numbers of negative pregnancy checks. While the 21-day returns stayed almost normal, there was an elevated number of irregular returns. “The sows would be fevered right after breeding, get a bit sick, then lose the pregnancy,” MacDougald explains. As the days passed, the PRRS effect was felt in the farrowing rooms again, this time with high levels of mummified piglets and higher number of stillborn pigs, which hit a high of 17 per cent.

Because the effects of PRRS are felt through the pig production cycle, the financial costs are huge. MacDougald has increased the breeding target, but that is difficult to achieve, as sick sows that have not nursed litters properly do not cycle the same way as healthy sows. After the first wave of PRRS hits the farrowing room, the litter size in subsequent litters is smaller.

MacDougald’s staff has gone through the process of drawing blood from viremic pigs and vaccinating the herd with serum to ensure all the pigs in the herd have the same PRRS status. They are hopeful that by the end of April, all the animals will be negative and the herd will have a PRRS negative status again.

How much did the PRRS outbreak affect MacDougald’s bottom line?  “I would just be speculating,” he says.  “There are real dollar costs, but there are also opportunity costs that are very difficult to determine accurately.”  He is still working through the effects of the disease, but he figures that so far he has had a production loss of between 20 and 25 per cent for one quarter. Secondary effects of the disease continue to haunt the herd. “The best scenario is that the next quarter bounces back to the baseline for productivity,” he says. If it doesn’t bounce back, as is the case in some herds, the economic losses become even more serious.

Because his herd veterinarians, Dr. Doug MacDougald and Dr. Brent Jones, had learned more about the disease and how to treat it, Bill says he was not saddled with the huge veterinary and treatment bills that he was the first time PRRS hit his herd. During his first outbreak, he ended up vaccinating every pig that went out the door. “My vet bill just went berserk,” he laments. Doug and Brent have more informed treatments now, he says. Doing less vaccinating and blood testing helps at least to keep the veterinary bills down somewhat as PRRS makes its way through the herd.

Dr. Doug MacDougald agrees that it is difficult to put a number on how much PRRS actually costs. Even numbers that have come out of the United States from PRRS studies are just estimates, he says. Costs vary so much because there are so many variables, including herd structure, different viruses and treatment methods. After fighting their way through a devastating PRRS outbreak, many producers simply do not want to do the math and face the hard numbers. “We know it is expensive. To sit down after the fact and revisit it just adds pain to pain. That is the reality,” he says.

Sneezing in the nursery
Martin and Teresa VanRaay have been raising pigs on their farm near Dashwood, in Huron County, since the mid 1980s. They started with a 180-sow farrow-to-finish barn in 1982. Ten years later, they expanded to 500 sows and sold weaner pigs until they completed a finishing barn around the corner in 1993. Subsequently, they have finished all the pigs they produce and, since 2001, have bred their own replacement animals.

Throughout that time, they have gone through two depopulations – once in 1992 when they were expanding and renovating their facilities and again in 2001 when they switched to purebreds and started producing their own replacements.

In the summer of 2004, they were not vaccinating against anything. They started hearing sneezing in the nursery and the piglets lost their normal healthy appearance. There were no abortions and no increase in prewean mortality at that time.

They started vaccinating for PRRS, but Martin was not happy with the outcome. “In my opinion, the vaccinating just confused the testing. Now we had the vaccine strain in the barn,” says Martin. “We spent all this money on vaccinating, but will never know if it was worth it,” he adds.

When they went positive for PRRS in 2004, they stopped supplying gilts to anyone. They kept about 70 purebred animals in order to breed their own replacements, but switched the remainder of the herd over to crossbred females. They currently do not bring any animals into the herd and have a replacement rate of about 45 per cent.

By vaccinating for PRRS and doing biofeedback, the VanRaays were able to walk PRRS out of the barn. But, within six months of having the PRRS break, the pigs started coughing and they realized that they had a mycoplasma outbreak.

Some 18 months later, in March 2006, they broke out with PRRS again, this time a new strain. They were now battling PRRS and mycoplasma, which gave circovirus the opportunity it needed to start affecting the pigs.

In November, they began vaccinating piglets at three to six weeks of age for circovirus with the Intervet vaccine and boosting them three weeks later. They are also vaccinating for mycoplasma, which is the most costly part of their disease-control program. Martin estimates that the mycoplasma vaccine alone costs $10,000 per year, plus the time it takes to administer it.

This vaccination program has improved nursery performance and mortality rates, compared to their previous losses of as high as 30 animals per week. In spite of the health challenges they faced, the VanRaays realized their highest ever total wean number last year – 11,717, compared to 11,239 in 2005 and 9,378 in 2004. They attribute this to more consistently hitting breeding and farrowing targets. The VanRaays normally wean between 200 and 240 animals and farrow 24 sows per week. 

When disease hits a pig barn, one of the first things people want to know is how it got in the barn. So it is important to look at all aspects of biosecurity, as well as the wider environment. At the VanRaays, their philosophy is that the inside of the barn is a separate world from outside. Transportation between the farrowing barns and the finishing barns is done with their own bus, which is washed regularly, especially if it leaves the farm.

The sow barn and finishing unit are operated as one barn. Employees shower as they go into the sow unit, but go back and forth freely in their own vehicles. However, all clothing and boots are changed in between the barns and they take care to wash their hands thoroughly.

The truck used to haul the market pigs is contracted, but is washed before coming on the property, and the VanRaays provide the truckers with clean boots. The pigs are picked up on Friday mornings, which Martin acknowledges is not ideal, but it fits in with their work schedule. Martin has not seen any proof that their disease problems are originating from trucks coming on the property. “Anything we’ve seen, we see first in the nursery,” he says.

Prior to 2003, there were not many pigs close to the VanRaay barns. The closest 500-head market hog barn was located three kilometres away. Within a five kilometre radius, there were just a couple of barns, explains Martin. Starting in 2003, pig density in the area increased. A 4,000-head finishing barn went up within one kilometre of the VanRaay operation and pigs were finished seasonally across the road from the finishing barn. Martin and Teresa are careful not to suggest, however, that these barns were the cause of their problems.

The VanRaays are blood-testing piglets for PRRS. If these tests come back consistently PRRS-negative, they will begin a partial depopulation in the nursery and finisher to try and eradicate PRRS from those locations in the summer. BP