The Guardian has reported figures from the UN’s Food and Agricultural Organization (FAO) which indicate that 1.8 billion live chickens, pigs, sheep, goats and cattle were moved across borders in 2019. Individual countries tend to specialise in which animal they focus on for export production, and fattening can occur in a different country to production or slaughter.
The risks for the animals include stress during loading and unloading, injury, hunger, thirst and exhaustion, and low slaughter standards.
The OIE’s Terrestrial Animal Health Code states (in several places): “The amount of time animals spend on a journey should be kept to the minimum.” This is a fundamental principle of animal welfare that should not be left to market forces. But with signatories including EU countries (trafficking animals here there and everywhere at multiple life stages) and Australia (pushing live ex as hard as it can), there is clearly an incentive to a selective interpretation of "minimum"!