PZP is the acronym for the chemical compound porcine zona pellucida, which is used in contraceptives for managing the population of wild horses and other animals. There are a few synonyms for PZP that you might come across. Some of these synonyms include immunocontraception, fertility control, and contraception vaccines. Essentially, they are all referring to the same process of using vaccines to control the number of animals that are able to reproduce. While some people may be unfamiliar with the term PZP, these synonyms can help them to understand the concept behind it and the importance it holds in animal conservation efforts.