In ways seldom discussed, Shakespeare’s The Merchant of Venice provides telling evidence of the global trade in livestock—Venice was the center of the eastern Mediterranean cattle trade—and its concomitant networks of contagion. Building on the work of other scholars working in the early modern period, I reconsider some key passages in the play, many about sheep, in the context of the disease outbreaks that devastated both Italy and England in the sixteenth century. These outbreaks set in motion rigorous protocols adopted by the Venetian Senate for isolating infected animals, quarantining herds, halting cattle shipments, and, in some cases, prophylactically slaughtering herds in danger of being infected. To read Shakespeare—who was, after all, the son of a leather tanner—in light of his knowledge of cattle and the cattle trade is to confront, in unexpected ways, new perspectives on the real and imagined cross-species infections often glossed over by anthropocentric literary interpretations. Central to this chapter, and to the play as a whole, are tensions between Christian pastoral power and growing fears about an amoral, or even immoral, animal trade driven by greed, violence, and exclusion.