**Abstract**

In this chapter, we review the sexual behavior of domestic pigs, and the visible or measurable anatomical features of the pig that will contribute to detecting sows in estrus. We also summarize olfactory organs, and the effects of a sexual pheromone on pig's biology and sow reproductive performance. We discuss the role of a live boar in the heat detection where the female is in breeding crates. However, there is an increasing interest in being able to breed sows without a boar present. Farm workers must be trained on the fine points of estrus detection so that they can work in a safe and productive setting. After a review of olfactory biology of the pig, the chapter explains how new pheromonal technology, such as BOARBETTER®, aids in the process of heat detection with or without a live boar. To achieve reproductive success, the persons breeding must assimilate all fine points of pig sexual behavior and possess a clear understanding of what they should be looking for in each sow they expect to breed.

**Keywords:** pigs, reproduction, sexual pheromone, sexual behavior
