Is a dose a breeding? Is a straw a dose? How many straws in a dose? How many sperm in a dose? These are often questions we hear from our clients when purchasing or using frozen semen. There is so much variability in the format of doses sold throughout the world that it can be confusing at times. To ensure you have the best opportunity of success when breeding your mare it is important to understand all the elements that determine an adequate dose of frozen semen. Here we review frequently asked questions that relate to what constitutes a dose of frozen semen.