By Brenna Wachtendonk, Igor A.D. Paploski, Dennis N. Makau, Mariana Kikuti, Cesar A. Corzo, and Kimberly VanderWaal, University of Minnesota

Pigs on sow farms die of various causes including some highly contagious diseases. Studies have shown that the odds of a porcine reproductive and respiratory syndrome outbreak in farms that perform rendering as a disposal method for dead animals are higher than in farms that perform composting.

Characterization of the dead animal facilities, structures, practices and procedures is then needed to mitigate the risk associated with dead animal removal in sow farms.

Materials and methods

Ten standard operating procedures from nine different systems were collected, evaluated and summarized for clarity, completeness and detail. The SOPs were summarized into five different sections: biosecurity, dead animal gathering space in the barn, sow/piglet removal from the barn, transport out of the barn and final destination. Data collected from the SOPs was used to develop a questionnaire for on-site visits to further characterize dead animal removal.

The questionnaire was divided into six different sections: farm characteristics, dead animal removal area loading, dead animal gathering space/removal area, removal of dead animals from the barn, rendering box/compost pile/incinerator and record keeping. Four farms from two different farm systems were visited and the questionnaire was filled out for each. The first farm visited was a pilot to test the questionnaire and not all questions on the final questionnaire were asked on that farm. 

Results

SOP Characterization

The SOPs exhibited varying levels of detail, ranging from the longest at 12 pages to the shortest at 11 lines. Regarding biosecurity, most SOPs outlined the timing in which the dead animal removal should be performed, with specifics on PPE, positive-pressure fan activation, and re-entry restrictions. However, inconsistencies were noted in instructions for personnel assisting from within the farm.

A majority of SOPs stipulated a space for the gathering of dead animals, but on three SOPs this space was the piglet load-out chute. Loading this room was mentioned to be done using Hercules, snares and dead carts in seven SOPs. Seven SOPs emphasized cleaning and disinfection of this room.

Methods for dead sow removal, such as dropping them out of the barn, were detailed in seven SOPs, but specifics varied. Dead piglet removal was less consistently addressed, with tools for dropping mentioned in some SOPs.

Transportation methods, primarily tractors or pickups, were cited in eight SOPs, but cleaning of these machines and the need to follow designated paths were often overlooked. Final destinations for disposal were inconsistently mentioned in six SOPs, highlighting the need for greater clarity and uniformity.

Farm visits

We then visited sow farms to further collect information on the structures and practices involved in dead animal removal from those farms. Four farms were visited, three employed composting and one resorted to rendering for dead animal disposal. Notably, dead animal removal was consistently scheduled as the final task of the day across all farms, which did not change as a function of the farm’s PRRS status.

Daily removal of dead sows from the barn involved dropping them onto the ground or into a skid loader bucket. Despite this task being scheduled to occur daily, environmental conditions (mostly direction of wind) dictated if it occurred every day.

Transport to rendering or composting utilized tractors or skid loaders, with limited disinfection efforts noted. Rendering and compost areas were exposed to wildlife and all farms reported seeing wildlife with varying degree of interaction of the wildlife and the carcasses.

Recordkeeping of dead animal removal varied, two farms had a log for emptying of the dead animal room with dates, times and personnel involved. Two of the farms had audits on dead animal removal performed. One of the compost farms recorded what sow was in each bay, when the bay needed to be rotated, and the number of sows per bay. Two of the farms performed audits on dead animal removal performed.

Conclusions and implications

Writing SOPs for different farms poses challenges due to the need for specificity while maintaining adaptability. Striking a balance between providing clear instructions and maintaining flexibility, while ensuring the document is not too extensive can be intricate. Additionally, addressing the unique requirements of different farms requires meticulous consideration, making it challenging to create a one-size-fits-all document.

Regarding biosecurity surrounding dead animal removal, we recommend including information on the timing of dead animal removal, specifying the appropriate personal protective equipment to be worn, and outlining the steps for personnel involved in dead animal removal, including post-task procedures such as ability to reenter the farm, showering, downtime, etc. Efforts to describe the exact procedures that should be performed to remove the dead animals from the farm should be made, particularly regarding details on how to remove animals from the farm and how to get them to the composting/rendering box.

Another topic that we found helpful to include is cleaning and disinfecting of both machinery/tools used to carry dead animals and the rooms in which dead removal-associated tasks occur (how often should cleaning be done, what type of disinfectant, dilution and procedures, and what needs to be cleaned and disinfected). Many of these considerations on the SOPs tend to be largely farm-dependent based on the structures and facilities in place on each farm. As so, system-wide SOPs should include complementary farm specific plans to assist with training, audits, and compliance with dead animal removal processes

Complacency regarding biosecurity measures during dead animal removal on a farm may increase the risk of disease occurrence. Failing to adhere to rigorous biosecurity protocols may result in the spread of pathogens present in dead animals. As such, SOPs are important tools that help outline what is expected, train employees and serve as an audit instrument to ensure tasks are being adequately performed. Strict adherence to biosecurity protocols is crucial to mitigate the risks associated with dead animal removal and ensure the health and safety standards of the entire swine farming operation.

This research was funded by the Swine Disease Eradication Center.