*Drs. Sam Holst and Brad Leuwerke are with the Swine Vet Center in St. Peter, Minn.

DIARRHEA in the farrowing house can be one of the more frustrating challenges swine producers and veterinarians face.

The effects -- including negative impacts on weaning weight, pig quality and, often, preweaning mortality -- make it a necessity to control farrowing scours. Unfortunately, control is not often straightforward and requires veterinarians to be good on multiple fronts.

Regardless of the specific pathogen(s) involved, the fundamentals behind eliminating preweaning diarrhea are a balance of: (1) immunity, (2) sanitation and (3) environment.

Immunity

Neonatal immunity can be broken down into two categories: passive and active immunity.

Passive immunity happens when an offspring acquires antibodies and immune cells from its mother. In the case of pigs, this transfer occurs after birth by way of colostrum intake. This provides rapid immune protection.

Active immunity is generated by an individual animal following exposure to pathogens (or vaccines) and is slower to develop compared to passive immunity.

Although there is limited science on what the best method is to consistently protect against the onset of scours in piglets, we do feel that, due to the early onset for most diarrhea-causing pathogens, passive transfer by way of colostrum is a necessity in scours control.

So, if passive transfer is so important, how should gestating sows and gilts be prepared to make the best colostrum possible for diarrhea control? The most common methods include a combination of controlled pathogen exposure (feedback) and vaccination prior to farrowing.

Controlled pathogen exposure builds an immune response to farm-specific pathogens and is often carried out multiple times (up to a half-dozen) during the later stages of gestation to increase the likelihood that all sows and gilts mount an immune response. These methods are often used as part of gilt development to avoid having the first exposure occur during gestation, which can increase the risk of pregnancy loss, fetal mummification and abortion.

Controlled exposure should be done far enough apart from farrowing (more than three weeks) so that the active pathogen shedding does not occur after arrival into farrowing. Additionally, the materials collected for controlled exposure must be fresh (i.e., morning collection for afternoon administration) to ensure feedback quality.

Commercial and autogenous vaccines administered during gestation are also good tools for broadening the level of immunity generated prior to farrowing.

Stimulating a vigorous immune response in sows and gilts is the crucial first step. Just as important is having a system in place to ensure that piglets receive an adequate amount of colostrum in the few hours following birth. Attending the most births possible, drying piglets after birth so they have energy to nurse and utilizing techniques like split-suckling as the number of pigs born in a litter increases are all ways to increase colostrum intake.

Sanitation

Common sense says sanitation plays an equally important role in the prevention of neonatal scours. Swine producers and veterinarians must remember that even the most robust immunity can be overwhelmed by an excessive pathogen challenge. Obviously, sanitation begins with the common routine of washing, disinfecting and drying before reloading a farrowing room.

Keep in mind that additional steps can be taken to reduce scours challenges. For farms that experience continual scours, we suggest adding degreasers to the cleanup process. Degreasers, applied according to label directions, help remove biofilms that harbor several pathogens that often aren't removed during normal washing and disinfection.

With the introduction of porcine epidemic diarrhea virus to sow farms, many farms relied on applying whitewash (hydrated lime and water) post-washing as an additional method to enhance the disinfection process. A typical whitewash creates a residue with a basic pH that kills most common pathogens. It is important that the whitewash be allowed to completely dry prior to loading sows into stalls as the solution is very caustic when wet.

Farrowing mats are frequent areas of contamination and need to be washed and disinfected as part of the standard sanitation routine. Having a surplus of mats available on farm allows for a rotation through a disinfecting solution prior to reuse. Dispose of mats when they become worn or frayed as this makes it difficult to clean them sufficiently. Also, periodic use of disposable mats (Compostamats) for a turn or two through farrowing can provide additional mat downtime.

Hallways are sometimes overlooked during sanitation procedures. Washing and disinfecting hallways following pig movements helps avoid tracking pathogens back into farrowing rooms.

While washing and disinfection are critical steps in the sanitation process, drying -- which is probably the most important part -- is often overlooked. Most of the common pathogens in swine production require moisture to maintain infectivity; therefore, removing moisture from the environment increases the chances of inactivating those pathogens.

Unfortunately, sow throughput can make it difficult to allow adequate time for farrowing rooms to completely dry, so put some thought into planning barn flow to allow adequate drying time to occur. Utilize drying agents, such as Quick Dry, on crate and mat surfaces to expedite the drying process in cases where a quick turnaround of farrowing is common.

Environment

Maintaining a comfortable farrowing environment is the third aspect of control as part of a scours reduction process. Temperature — and especially its fluctuation — is a substantial stressor for young pigs.

The room is divided into two separate environments: the "macro-environment" for sows and the "micro-environment" for the piglets. The goal is to maintain the room at a temperature that will maximize sow feed intake while utilizing sources of supplemental heat to create a warmer micro-environment for the piglets and prevent chilling.

Heat lamps centered above a mat or heated mats are commonly used to create a warmer piglet micro-environment. Ideally, a farrowing stall should have a heat lamp and mat or heated mats on both sides of the stall to provide enough space for the entire litter to lie down. One mat per stall is no longer adequate given the increased litter sizes associated with modern swine production.

Mats provide piglets with a draft-free place to lie as the mats block cool breezes arising from manure pits below the stalls. Additionally, ceiling inlets must be adjusted to avoid funneling cold air directly onto the piglet resting areas.

Treatment

Despite the best management practices to prevent preweaning scours, situations arise where treatment, which may include antibiotics, becomes necessary. A full diagnostic workup, including submitting intestinal samples from pigs that represent the clinical picture in the barn, should be conducted to help guide treatment decisions. Veterinary consultation should be utilized to make appropriate treatment decisions.

Also, if scours are present, put practices in place that reduce pathogen transmission from affected to non-affected litters, including:

* Avoid physical transmission by never stepping into farrowing stalls;

* Delay processing affected litters until diarrhea has resolved or at the end of the day;

* Change needles and gloves between litters;

* Disinfect processing equipment between litters, and

* Do not move piglets from litters with scours.

Summary

Neonatal diarrhea can have significant effects on the size and quality of weaned pigs. It is known that an outbreak of scours in the farrowing house will lead to increased preweaning mortality.

Control is commonly multipronged and includes developing herd immunity, establishing a sanitary farrowing facility and maintaining a comfortable environment. Where scours occurs, treatment decisions should be developed based on a thorough diagnostic investigation.

Controlling farrowing diarrhea is possible and is crucial for the highest-quality weaned pig. 

Volume:87 Issue:20