A recent a study to determine if using a conveyor to load pigs into the top deck of a straight deck trailer could lower the stress to which pigs and handlers endure during transportation concluded that while feasible, there was little advantage. The study, conducted by Donald C. Lay Jr., USDA Agricultural Research Service, determined that swine producers can choose to load pigs with traditional ramps or a mechanical conveyor without decreasing animal welfare.

Based on behavior of the pigs they had similar experiences in both treatments. Conveying the pigs into the trailer did not decrease their stress or increase it. Total time to load was the same. No change was seen to the handlers either.

Process of the study

The point of the study was to reduce stress to animals during handling and their handlers by self-movement of pigs during loading and unloading.

Weaned pigs and nursery pigs were the two types of groups used to test the idea. Weaned pigs were moved in groups of 20 while nursery pigs were moved in groups of 10.

Pigs used as a control group were moved up the ramp without the conveyor belt moving. Controlled grouped pigs were moved using the conveyor in-motion. Heart rate of two pigs per group, as well as the handlers’, were recorded during loading.


Pigs were held in the trailer for 30 minutes so their heart rate could be recorded. After, they were unloaded and moved to a holding pen for an additional 30 minutes so their heart rate could again be recorded.

Over 111 million pigs are transported from finishing sites; the same can be said for moving hogs from farrowing sites to finishing sites.

Pigs are often known for being high stress, and limiting this issue at the time of transportation is almost impossible. Eliminating transportation is inevitable because weaned pigs and nursery pigs need to be moved to growing facilities and then finished pigs need to be moved to the harvest plant.

Sloped ramps are foreign to pigs, therefore they may induce the stress level of hogs when using them. “However, said ramps can’t be avoided due to design of facilities at finishing sites, packing plants, and the vehicles used to transport animals,” said Lay in an industry summary of the study.

Intense handling that can happen during movement of hogs might causes stress on operation managers along with other livestock handlers and can create an abundance of stress in the hogs that may not otherwise occur. Use of a conveyor belt may reduce the stress level in both the animal and the handler, therefore making the process much easier.