The global trade in live farm animals has more than quadrupled in size over the past 50 years, but patchy regulation means animals may be put at risk on some journeys, or exposed to cruelty when they reach their destination.
Every year nearly 2 billion farm animals are loaded on to trucks or ships and sent to new countries in journeys that can take days and sometimes weeks. Every day, at least 5 million animals are in transit.
As the trade has grown, profits have rocketed. In 1988, the global trade in all live animals was worth $716m (£548m); by 2017 that had risen to $21bn, according to Comtrade data. These figures do not take inflation into account, but the rise has massively outstripped inflation over that period.