For research purpose their should be stricter laws put in place to make it harder for this to be done also many new methods have emerged to study these diseases and such. Educating the public on what goes on with these animals will also help the cause.
For spaying and neutering more low cost and free surgeries need to be offered so many of the animals on the streets can be trapped and spayed/ neutered for a low cost and then released back. Also new laws made so breeders can't get away with as much and help lower the population.
There needs to be new rules of shelter codes and making sure the conditions are up to date. Also rules on cutting down on euthanization and creating No Kill Shelters will be ways to help end animal cruelty.