SHIC Wean-to-Harvest Biosecurity: Comparing Efficiency and Efficacy of Automated versus Manual Power Washing Final Report

A study funded through the Swine Health Information Center Wean-to-Harvest Biosecurity Research Program, in partnership with the Foundation for Food & Agriculture Research (FFAR) and Pork Checkoff, recently completed an evaluation of pressure washing tools and methods to enhance biosecurity and overcome labor shortages. Led by Dr. Francisco Cabezon, vice president of Pipestone Research, the study compared the efficacy and efficiency of an automated power washer to a manned power-washing crew, with evaluation of cleaning time, manpower time, water usage, and cleanliness rate.

Read the full report here.

Overall study results showed water usage was greater for the robotic power washer compared to manual washing across two seasonal wash events. Further, the overall time required to wash barn rooms was greater with the robotic power washer compared to manual washing. The robotic power washer rooms required additional manual wash time to meet sanitation goals for a clean room. The evaluation showed power washing needs at facilities are time and resource intensive and the robotic power-washer prototype did not provide adequate savings in manpower or water usage. Although manual labor hours were reduced by robotic power washing, further refinements are needed due to washing time and water requirements.

SHIC, along with FFAR, a non-profit organization established in the 2014 Farm Bill,  and Pork Checkoff, partnered to develop the Wean-to-Harvest Biosecurity Program to investigate biocontainment or bioexclusion engineering controls (modifying equipment, physical barriers, site design, ventilation, robotics, or other technologies) that will help overcome labor shortages and the need to share personnel, such as with loading, vaccination, or cleaning and disinfection crews, across sites in a production or contracting service network.

The pressure washer study was conducted in a 2,400 head wean-to-finish barn with two rooms of 1,200 head capacity (196 feet x 50 feet) with 44 pens each. A group of nursery pigs were placed in the barn and raised until harvest. The barn was then cleaned, with one room washed using traditional manual power washing methods from a contract service, and the other room cleaned using a railed robotic power washer prototype, followed by a manual power wash to remove any additional manure (touch-up post robot). The trial consisted of two washing events (August 2023

and February 2024) for comparison and seasonal variation.

In the room washed with the rail robotic power washer prototype, four rails were installed (two on each side of the room divided by the central hallway) to cover the pen floor and side walls at a maximum height of 10 inches from the slat level. The rail robotic power washer prototype consisted of a trailer head carrying a rotary nozzle connected to a gas power washer. The trailer head was battery powered, and the speed of the trailer on the rail and the speed of rotation of the nozzle could be adjusted. Two different rotary nozzles were tested. The robot power washer with a single rotary nozzle was set to move through the rails at an average speed of 11.0 inches per minute, with a nozzle rotation time cycle of 22 seconds (August 2023 data). In the case of the double rotary nozzle, the robotic power washer was set to move at an average speed of 14.8 inches per minute, with a nozzle rotation time cycle of 30 seconds (February 2024 data). In both cases, the speed of the trailer head and rotation of the nozzle were adjusted to achieve two hits per slat.

Multiple methods were used to evaluate cleanliness (pre-wash, post-wash, and post touch-up), including 1) visual assessment, 2) adenosine triphosphate measurements to assess organic material, 3) bacterial culture with dip slides, and 4) a reverse-transcriptase real-time PCR (RT-qPCR) for rotavirus detection. There were 12 pens assessed in each room, which were equally spaced throughout the room. Five sites in each pen were assessed: fencing, floor, wall, waterer, and feeder.

In August 2023 (single rotary nozzle test), total water usage in the robotic power washing room was 8,396 gallons in comparison to 6,211 gallons in the manual power washing room. Total washing time in the robotic power washer room was 22.1 hours (13.0 hours of robotic washing and 9.1 hours of manual touch up washing) in comparison to 10.5 hours of manual power washing in the control room. The manual washing labor time in the robotically washed room was reduced 13% (1.4 hours), but total washing time was longer by 11.6 hours.

In February 2024 (double rotary nozzle data), total water usage in the robotic power washing room was 10,897 gallons in comparison to 7,526 gallons in the manual power washing room. Total washing time in the robotic power washer room was 19.3 hours (10.1 hours of robotic washing and 9.2 hours of manual touch up washing) in comparison to 13.3 hours of manual power washing in the control room. In this case, manual washing labor time in the robotically washed room was reduced by 31% (4.1hours) with the robot, but overall washing time was longer by six hours.

Cleaning score differences before and after washing were significant for each power washer method, at all sites in a pen, and in each testing method. The visual cleanliness trend was from very dirty to clean or very clean. For the robotic power washed room, the post-wash touch-up by the manual power washing team was necessary for the median value to reach the “Very Clean” score.

Greater bacterial count, higher rotavirus detection, and increased ATP levels were found after the washing process for both wash methods. Power washing does not clean the barn, it is solely a means to remove debris and must be followed by a disinfection process. Power washing should be completed to the necessary level to ensure that disinfection can be performed effectively.

Cleaning expectations of this barn were extremely high and could explain, to some degree, the long touch-up process. The robotic power washer cannot easily access the feeders and as such, the washing crew spent considerable time washing the feeders. The number of feeders in the barn will be a limiting factor to the efficiency of the robotic power washer. The barn used for this research has a low pigs:feeder ratio (27 pigs per feeder, doubled one-hole wet dry feeder). Another limiting factor for the automated power washer was the number of rails and their positioning. In the current study, four rails were installed in the room. This allowed walls to be washed at a maximum height of 10 inches from the slat level; however, the robotic washer did not cover the central hallway. Additional rails could increase the covered area by the rail power washer, but it would represent additional costs for producers and time of operation.

Power washing is a critical step for pathogen reduction and is part of a comprehensive farm biosecurity plan, but it is time, labor and resource intensive. Further investigation of robotic power washing systems is warranted to be able to identify methods for effective and efficient use of this technology on-farm to help address challenges during labor shortages.

Foundation for Food & Agriculture Research

The Foundation for Food & Agriculture Research (FFAR) builds public-private partnerships to fund bold research addressing big food and agriculture challenges. FFAR was established in the 2014 Farm Bill to increase public agriculture research investments, fill knowledge gaps and complement US Department of Agriculture’s research agenda. FFAR’s model matches federal funding from Congress with private funding, delivering a powerful return on taxpayer investment. Through collaboration and partnerships, FFAR advances actionable science benefiting farmers, consumers and the environment. Connect: @FoundationFAR

Swine Health Information Center

The Swine Health Information Center, launched in 2015 with Pork Checkoff funding, protects and enhances the health of the US swine herd by minimizing the impact of emerging disease threats through preparedness, coordinated communications, global disease monitoring, analysis of swine health data, and targeted research investments. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. For more information, visit http://www.swinehealth.org or contact Dr. Megan Niederwerder at [email protected] or Dr. Lisa Becton at [email protected].