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National Hog Farmer is the source for hog production, management and market news
October 28, 2020
For baby pigs with underdeveloped immune systems, added stress is the last thing they need. Stress can cause neutrophil motility to slow down by around 50% and chemotaxis to decrease, and sometimes the immune system will overreact, resulting in extra inflammation and leaky junctions, particularly in the gastrointestinal tract. All these conditions can also lead to neonatal scours.
Deborah Murray questions if sow farms are doing everything possible in the farrowing room to reduce stress. Some stress is unavoidable, as it is "just the nature of the game," but the veterinary services manager for New Fashion Pork in Jackson, Minn., says major stressors for baby pigs are environment and ventilation.
It is important that sow farm managers understand ventilation. Murray says step one is to understand the fan size in the room as well as the brand and motor type, so the cubic-feet-per-minute requirements for that room can be understood and calculated. Many times, farm managers do not know what size fans are present and are making incorrect assumptions on CFMs produced as a result. It's often assumed that when the farrowing room was built, the fan was built at the correct size, but Murray says that may not always be the case — and in some situations, the fan is greatly oversized.
"Where we may be a lot better off maybe just putting in a much smaller fan that we can run continuously, even if we can't run that through the controller, with a simple on-and-off switch for minimum ventilation," Murray says.
Here are other environmental questions Murray often poses to farm managers and staff in the farrowing room.
• Are bandwidths adjusted differently for spring and fall versus summer and winter months?
• Are heaters sized correctly for the room size (or was a larger heater almost the same price, so why not?)
•Can the heaters be adjusted?
• Are inlets set correctly and adjusted as needed? Can we open all inlets and still achieve proper air speed (800 to 1,000 feet per minute) while on minimum ventilation?
What effect can poor ventilation have on piglets? Murray offers one example from a New Fashion Pork site, where the farm had two different-sized rooms, with 24 sows and litters in one room and 40 sows and litters in the other.
The minimum CFM requirements should be 480 on the smaller room and 800 on the larger; the farm had its fans set at 50%, however. The 18-inch fan only put out 1,770 CFMs, and then staff was purging that fan at 30 out of 285, so then they ended up with only 186 CFMs. The farms should have been running the smaller room fan at 77 and running the larger room fan at 129 to meet minimum requirements.
"Our rooms were very humid. They were gassy, and the sows didn't milk as well and of course, we created more scours and a perfect environment for that bug load to grow in those high-humidity rooms," Murray says.
The veterinarian offers another example where a farm had its current temperature settings at a reasonable set point, but Stage 1 fans were set to ramp up only a half-degree above the set point. As they further checked the controller settings, the New Fashion Pork team found that instead of the heaters coming on below the set point, they were actually triggered to come on above the set point and run simultaneously with the fans.
"As you could have guessed, that created a very drafty environment with our original settings — and, of course, not to mention expensive," Murray says. "We're just blowing propane out the door, and in this example, as you may have guessed, all the rooms that had settings this way were scouring."
The piglets' behavior can also be a clue something is off in the environment. Are they piling or lying off the mat? Are they drinking from the water nipple more than the sow?
Murray says it is essential to make sure the heat mats are working. Are you checking the temperature routinely, and is the curve being set or reset with each room?
Also, make sure the heat lamps are being adjusted properly. Are there bulbs available for replacement? Have the bulbs been set up at the correct height so when the piglets hit the ground, they have a warm environment?
After ventilation, Murray says basic crate sanitation is a must, and the rinse-degrease step should not be skipped.
"That's kind of like having your leftover spaghetti in your Tupperware or Rubbermaid container, and trying to just wash it out without any soap," Murray says. "We're not going to do a good job — and in particular, if we use cold water for that. Do we have hot water wash or disinfectant? Obviously, we want to make sure we get that at the right rate."
Farm staff should also properly inspect rooms, allowing time to touch up or rewash as needed, and to ensure the rooms are given enough time to dry. Murray advises not stepping in crates and washing whole rooms, and if needed, changing gloves and aprons between litters to prevent transmission.
Finally, treat each room separately. Limit movement of sows in and out of rooms during a scour break, and always roll pigs forward, so scours are not being moved back and introduced in a younger room.
Murray says it's also important to remember that not all boot baths are the same, and there is quite a bit of difference between the powder and liquid products. "With the liquid boot bath, we almost have to change those with almost every use, because if we get organic matter in those, they become no longer effective," Murray says.
Another key factor in site cleanup, as well as sow farm sanitation in farrowing, is whitewashing. Whitewash application provides a physical barrier for cracks and crevices, where viruses and bacteria can survive.
"Especially if I have a viral challenge, it gives me my time and temperature, if nothing else, to kill that pathogen before the pigs are exposed, because my farrowing rooms are nice and warm," Murray says. "I have that, essentially a layer of paint, on everything; and it also is a very nice visual, so we can see exactly where we've been or maybe where we've missed."
However, Murray warns that whitewashing is caustic if the pH is above 13, and personal protective equipment must be used when applying. Rooms also must be allowed to dry completely prior to pig placement.
The next step in reducing scours in the farrowing room is making sure that once those piglets are born, they are getting colostrum.
"Because we know that we can have the best vaccine programs in the world and the best immunity on our gilts, but if the piglets don't ingest that colostrum, of course they're not going to get any of that," Murray says. "We know, with this high number born alive, we're going to have to do something, maybe a different intervention than maybe what we've done in the past, and so split suckling can be very helpful in that."
By incorporating split suckling rings, a few of the bigger pigs that may have been born first can be pulled off, allowing the next pigs coming to have a chance to nurse. Murray says it works very well if managed properly, but it does take some management and biosecurity to ensure those rings get as clean as possible, and pathogens are not shuffled around the room with the rings.
While sow and gilt immunity can be built up through vaccination programs, Murray says one other strategy that can be used is live oral exposure through feedback. Feedback may be used to boost immunity for things that are already on the farm, or to homogenize a herd if there is a new break.
Feedback is generally done for scour prevention in the farrowing house, but more so for gilts than sows unless the pathogen is novel — such as porcine epidemic diarrhea virus or porcine deltacoronavirus. It can also booster immunity for other pathogens like Seneca Valley virus A and HEV (hemagglutinating encephalomyelitis virus).
Immunity from feedback is not lifelong, though. Most, if not all, gilts have previously been exposed to rotavirus in the nursery. Gilts exposed to PEDV at a young age can break again and shed as they mature.
While there are various benefits to feedback, Murray says it's also important to keep welfare concerns in mind. Some states do not allow tissue feedback, and there can be concerns from consumers as well as farm staff.
It can also be difficult to collect clean noncontaminated samples.
"Typically, we would be using a tissue homogenate when we've done feedback, and we would want to collect that from scouring litters when they just start to scour," Murray says. "That's really the primary problem. If there has been scouring for a long time, then we start to get some other secondary pathogens that really aren't our primary issue."
What pathogens are essential for feedback? Murray says generally, only the pathogen of interest. For pre-farrow and mature gilt feedback, that could be rotavirus A, B, C and E; HEV; parvovirus or farm-specific E. coli. Whole-herd feedback can be used for PEDV, PDCoV, SVV, porcine reproductive and respiratory syndrome virus — and generally, any viral pathogens.
Feedback timing can range from two to four weeks, or six to nine weeks pre-farrow for rotavirus. If this is the piglets' first exposure, Murray says the shedding period can be quite long.
It can take multiple doses of feedback pre-farrow for E. coli or rotavirus. For whole-herd PEDV, PDCoV and transmissible gastroenteritis, Murray says a one-time low dose has worked well.
Water quality is an important area in scour prevention. "We know we have a lot of mineral in the water," Murray says. "We can have a high bacterial load from that iron-loving bacteria."
Water lines can be cleaned, and since farrowing rooms typically are not empty very often, treatments can be run continuously. Murray says, however, to keep in mind that not every treatment option is going to treat everything. She advises talking with a water treatment specialist on what is being targeted before implementing any treatments.
Poor water can also cause biofilm formation in water lines. Lines can be blown out with high air pressure, but Murray says to keep in mind that this doesn't treat the line from the well to the point at which the pressure is introduced. Lines can be flushed with cleaners, peroxide or a combination peroxide-acid. Other rules of thumb include pulling all the nipples, repeating flushings and replacing lines.
Some treatments can be used at a low level when pigs are present, while others can only be used when the barn is empty.
Diagnosis and treatment
Once there is a scours issue in a farrowing room, Murray says it's important to find the primary problem. While the veterinary staff may perform necropsies to investigate, texts and photos from farm staff are critical for veterinarians to make an accurate diagnosis.
"Did it start with just one group, as a line in the sand? Is this a common problem that we see throughout farrowing? Or maybe we only see that at the very end of Room 16 and 17," Murray says. "Because that could mean maybe a ventilation issue there — as opposed to maybe it just started with Group 41, which could either be a new introduction, or maybe it's a vaccine compliance issue."
Once the problem has been diagnosed, treatment begins, but Murray says a permanent treatment is never a solution, and after a period, treatment will become ineffective.
"Our treatment is sort of buying us time to investigate the root cause of the scours, and hopefully fix it or eliminate it, so improving sanitation, maybe you put a new vaccine or better acclimate gilts," Murray says.
"We know every farm is a little bit different — different bugs, different challenges — so a lot of these products are going to be pretty farm-specific. I would encourage you to try them on your farm to know which product is going to work the best for you."
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