An isolation/acclimation (I/A) facility has helped improve swine herd health and development of gilt replacements for a Minnesota pork-producing family.
It's been just a year since Mark and Dede Kotewa completed construction of a 25 × 96-ft. I/A facility at their 400-sow, farrow-to-finish operation near Fairmont, MN.
The I/A unit utilizes the concepts of isolation and acclimation, yet is practical and cost-effective for the family farm, says Mark Kotewa. For example, the entire facility is attached to the farrow-to-nursery barn, connected by a hallway.
The I/A unit itself is divided into two separate rooms: an 8 × 25-ft. isolation room reserved for 35 to 40, 21-day-old gilt replacements, and the other for acclimation. The Kotewa's veterinarian, Mark Wagner of the Fairmont Vet Clinic, stresses the isolation room is totally walled-off from the rest of the I/A unit. A door to the room is always locked. It is only opened when gilts are moved from isolation to acclimation. Entry to isolation is from an outside door using a separate pair of boots.
The isolation room features its own ventilation and heating system, feeding system and separate, 8-ft.-deep manure pit. Plastic-coated slats provide comfort and warmth; temperature is maintained at 84° F upon entry and ramped down a few degrees each week. Pigs are fed a typical nursery diet and stay in isolation 5-6 weeks.
The acclimation portion of the unit is a fairly standard room, with gilt age groups staggered. Gilts move into acclimation at about 10 weeks of age, flow through the three pens as they grow and leave for the sow gestation barn at 28 weeks of age.
Gilts are assured of at least 12 sq. ft. of space in acclimation. Diets are fortified with extra calcium and phosphorus, compared to typical grow-finish rations. Additional ventilation provides plenty of fresh air during boar exposure. Pens feature concrete slats with some solid dividers to limit nose-to-nose contact.
The Kotewas believe having a confined I/A area has paid off in performance. Farrowing rate is running at a respectable 84%, compared to 70% in the past, remarks Dede. And pigs marketed/sow/year has climbed about a pig and a half in the past year, adds Mark Kotewa. Plus, from the first quarter to the second quarter of 2004, the weaned pig average climbed from 9 to 9.5, adds Wagner.
Mark Kotewa wonders why they waited so long to build the confined I/A unit. The previous I/A facility consisted of some Cargill-type outside facilities where gilts were placed at 100-200 lb. The Kotewas fought the weather extremes of southwestern Minnesota and the risk of area spread of major disease problems like porcine reproductive and respiratory syndrome (PRRS) and swine influenza virus (SIV).
Cull rates were also high in the Cargill units. With the new I/A unit, cull rates are running at a very respectable 3-5%, says Dede. She notes that gilts are culled mainly for feet and leg problems and belly ruptures, and seldom for health reasons. “If I bring in 35 new gilts, I can almost always count on raising 32 that will go on to the sow herd,” she says.
Now gilts develop better, it's easier to check heats, and biosecurity and health are improved, adds Dede.
“The health status of the breeding herd starts with the gilts and trickles on down through the whole operation,” remarks Dede. “To give the gilts these kinds of conditions to live in provides a lot of payback. This kind of I/A facility is reasonable and realistic for our small sow herd,” she says.
The gilt program is built around healthy replacements, stresses Mark Kotewa. PIC gilts purchased from a Wisconsin seedstock producer every eight weeks are certified PRRS-free.
PRRS herd stability is provided by applying serum therapy in the isolation barn. (To read more about serum therapy, see “Controversial PRRS Control Procedure Wins Advocates,” pages 20-22, June 15, 2004, National Hog Farmer.)
“We bleed a random sample of gilts about a week or so after they arrive,” explains Wagner. “They are tested for PRRS, and at the same time the oldest gilts are tested for PRRS to make sure they have been properly acclimated to the farm's virus, and that they are no longer shedding the virus.”
Mark Kotewa observes: “Bringing in PRRS-negative Isowean gilts and acclimating them to our farm has really worked to keep our whole sow herd PRRS stable. The focus is on minimizing PRRS activity in the sow herd, doing a good job with acclimation, and then dealing with swine flu, because we know being in a hog-dense area, we are always going to have a lot of flu problems.”
“Each group in I/A has a vaccine schedule all the way through the 28-week period they are in I/A, and there was just no possible way we could have implemented that with the outside (housed) gilts,” emphasizes Dede.
Proper gilt development, along with proper vaccine timing, are keys to getting the job done accurately, adds Wagner.
On arrival, gilts are blood tested to ensure maternal antibodies aren't present that would block SIV vaccine; gilts are then given their first dose of flu vaccine. About two weeks later, they receive their second dose of vaccine.
“We give them two shots in isolation because we know these gilts are susceptible to flu at a young age, so we want to make sure that we get them well-acclimated to flu before we put them in acclimation, where there are multiple ages of gilts,” says Wagner. Gilts receive a third flu vaccination prior to their move to gestation.
By keeping the PRRS virus in check, the swine flu program and related bacterial problems are reduced, he says.
Swine flu used to be a significant problem for the Kotewa's operation. Pigs were coughing and many pigs were just unthrifty, says Mark Kotewa. Some flu respiratory problems even showed up in nursing pigs.
“Initially, we did a blanket sow vaccination program, 2-3 times/year and it seemed to work well for keeping sows stabilized, but not always for providing weaned pig protection,” explains Wagner.
“When you have some nursery age pigs in the same air space as gestation and farrowing, sometimes the flu virus can be more active and serve as a source to reinfect sows,” he points out.
Because of the switch to a flu shot 3-4 weeks prior to parturition, sows have time to respond to vaccine before farrowing, in addition to passing maternal antibody protection onto their piglets, Wagner says. This program has provided flu protection through 6-8 weeks in the nursery.
All of this has made the Kotewas very pleased. Hog prices are the best they've been in years. And so, too, is the health of the family hog operation.
In the last five years, SIV has become a bigger disease threat for the southern Minnesota pork industry.
Before 1998-1999, the veterinarians at the Fairmont Vet Clinic (FVC) say they dealt with one main swine flu strain — the H1N1 “classical” strain, common since the early 1900s. Mostly, the virus blew through a farm, dealt some losses and blew back out again.
In the late '90s, the H3N2 flu strain arrived and changed all that. It started the flu evolution, agree FVC veterinarians Clark Huinker and Mark Wagner. The classical H1N1 strain has been mostly displaced by the “recombinant” H1N1 strain and H3N2. Both new strains can cause recurring problems and require treatment.
More flu is also diagnosed because of improved technology. FVC, for example, sends in suspect serology samples to the University of Minnesota and Iowa State University diagnostic laboratories to perform highly sensitive polymerase chain reaction tests to identify the virus and sequencing to characterize the nature of the virus detected.
A fast test called Directigen A can be run right in the veterinary clinic. It allows veterinarians to swab nasal passages and lung airways, providing non-subtype-specific identification of swine flu in a very short time, says Wagner.
Detection shows recombinant H1N1 seems to be more prevalent in the fall and H3N2 in January-March, says Wagner. The rest of the year is a toss-up.
Neither of the two main swine flu strains cause many deaths. Pigs with H1N1 cough more, while pigs with the newer H3N2 cough less, but tend to lie around more. High fever is common with both strains.
FVC veterinarians have seen more cases of swine flu this summer.
Marie Gramer, DVM, University of Minnesota Veterinary Diagnostic Laboratory, reports that an outbreak of swine flu in parts of southern Minnesota and northern Iowa this summer is probably due to sow herds left unvaccinated.
Summer produces the greatest number of swine flu cases in 4- to 8-week-old nursery pigs, reports Bruce Janke, DVM, Iowa State University Veterinary Diagnostic Laboratory. More cases in older pigs were observed in other months, particularly in the fall. Nursery pigs were the most common group affected during June-August 2003.
Janke says growing problems with swine flu may in part be due to mixing pigs from sows of different parities. It becomes difficult to achieve similar levels of immunity in different parities with numerous swine flu strains operating in a herd simultaneously.
For example, Parity 1 sows have lower antibody levels than Parity 4 sows on the same vaccination program, due to lack of herd exposure to circulating SIV strains, he states.
Maternal antibodies for swine flu degrade at a standardized rate, notes Robyn Fleck, technical services veterinarian for Schering-Plough Animal Health Corp.
“However, pigs from Parity 1 sows start with lower maternal antibody titers, and through normal degradation, become susceptible to SIV sooner than pigs from older sows that start with higher titers at birth,” she explains. Titers are measures of levels of protection or exposure.
Huinker and Wagner suggest now is the time to prepare for this fall's heightened flu season. Area surveillance can provide benchmarks on types of flu present.
Monitor herds for the virus. Wagner suggests collecting blood samples from gilts in isolation prior to placing them in the sow herd to make sure they've been properly acclimated or immunized.
Sow testing is a little more variable. On some farms, monthly serology monitoring is performed. On others, it is done less often. It depends most on the clinical history of the farm, he says. The point is to look for titer change following vaccination.
Standard strategy is to vaccinate sows to provide continuous protection against flu to nursery pigs, says Huinker. Mass vaccination and vaccination before farrowing are the two most common types of sow flu vaccination.
Before fall, producers may choose to booster the whole sow population. “The goal is probably focused more on providing stability to the sow population,” says Wagner. Other farms may vaccinate only gilts.
Vaccinate first with commercial products and then with autogenous products if initial results are inadequate, agree Huinker and Wagner.
Most important is tailoring a control program to a specific farm, stresses Wagner. Properly isolate and acclimate replacement animals to reduce PRRS spread, and by doing so, reduce the impact of flu if it strikes.
Practice good management. Change boots and coveralls, wash hands and shower in and out, says Huinker. If there is flu in the finisher, work in that barn last.
And for pigs infected with flu, provide electrolytes and aspirin, and fortify rations with vitamins and minerals, notes Wagner.
Fairmont, MN, swine veterinarian Clark Huinker says he seldom diagnoses swine flu problems in nurseries — except in pigs purchased from outside the area.
That usually refers to pigs brought in from Canada from unvaccinated sow herds. These naïve pigs become infected once they are introduced into U.S. herds, he says.
In Canada, most of the cases of swine flu submitted to the University of Guelph Animal Health Laboratory at Ontario show only signs of classical H1N1, says Susy Carman, veterinary virologist. Virus sequencing is done at the University of Wisconsin-Madison. So Canadian producers mainly vaccinate for this strain of the flu virus.
But some Canadian producers who export pigs to the U.S. vaccinate for H3N2 swine flu, because they realize the pigs are at risk after they cross the border, adds Gaylan Josephson, swine health adviser at the Guelph lab.
“We also seem to be seeing more multiple agents in respiratory problems, particularly in the nursery,” notes Josephson.
That view is echoed by Huinker. Sometimes flu hits finishers; they can be treated with water medications and it is over. But when secondary bacterial problems like Haemophilus parasuis and Actinobacillus suis really hammer finisher pigs on top of swine flu, consider vaccinating finishers early for protection.
If Canadian pigs break early with flu in U.S. nurseries, sows in Canada should be vaccinated prefarrowing, advises Robyn Fleck, Schering-Plough Animal Health technical services veterinarian. Later breaks on U.S. finishing floors can be controlled by vaccinating pigs upon arrival.
“This is because pigs that break with SIV within a week or two of arrival in a U.S. nursery or wean-to-finish barn aren't receiving adequate immunity from the sow,” she says. “Pigs that break with flu in the finisher have simply lost protective maternal immunity.”
Developing the proper control plan hinges on broad-spectrum flu protection and good communication between U.S. and Canadian veterinarians, adds Huinker.