The numbered replicator recipes that Data uses to feed his cat Spot, patiently adjusted over the years in an effort to find one that she will accept.
Feline supplements are replicator food programmes written by Data for his cat Spot aboard the Enterprise-D. Each has a number, and there are a great many of them.
The first is seen in the episode Data's Day, set in 2367, when Data orders a dish for Spot in his quarters as part of his daily routine. In later episodes, such as Force of Nature, he is still experimenting with new formulas and with training methods, with little success, since Spot is at least as stubborn as he is.
The supplements are part of the running story of Data as a devoted pet owner, which also includes his Ode to Spot and the difficulty of finding crewmates willing to look after her. Spot survives the destruction of the ship in Star Trek Generations.