The Canadian Food Inspection Agency said its agents monitor the loading of horses for each air shipment to “verify that the horses are fit and will be transported humanely”. It said it was aware of five deaths related to air shipments to Japan since 2013.

Most of the journeys from Canada to Japan are completed in about 22 hours, it added, with the animals off-loaded immediately to a quarantine station adjacent to the airport.

The 28-hour time limit on journeys was introduced in February 2020, with the industry given two years to transition from the previous limit of 36 hours.

Transporters and exporters are required to use crates that allow horses to stand in their “preferred position” when calm. “This requirement does not prohibit incidental contact with netting if a horse rears its head,” the agency added.

Exporters are required to prevent overcrowding and must ensure the animals placed together in crates are “compatible”. Groups of four horses may be shipped together, it said, provided there is a minimum of 7 sq metres of available floor space.

Speaking anonymously, a Canadian company that supplies live horses for export to Japan said in his experience horses usually ranged in age from one to three years old and were always accompanied on flights by a groom who monitored their health and welfare.

“There is great government oversight during the entire process. Internal and external vets are also involved. We are constantly under the microscope,” said the source. “Animal welfare is the highest priority.”