First there were pet therapists. Then came yoga for dogs. Now there is even a dedicated pet airline, Pet Airways, which charges $199 to fly pooches between New York and Chicago “in the main cabin, not in cargo”. Yet all this is small change compared with the $19bn that pet lovers and farmers spend each year on animal medicine. This has not been lost on Sanofi-Aventis and Merck. On Thursday, they launched a two-step bid to overtake Pfizer as the leader in animal health.

The deal is a clever one. Sanofi will first pay Merck $4bn for its 50 per cent stake in Merial, its animal health joint venture with Sanofi. Merck needs to offload its half of the world’s third-biggest animal medicine business for its $41bn takeover of Schering-Plough – owner of number two company, Intervet – to win competition approval. Owning all of Merial, meanwhile, helps Sanofi move away from a reliance on blockbuster human drugs.