One option to safeguard a breed is to use it as one of the components of a cross-breeding programme. However, any use of pure-bred females to produce cross-breeds will reduce the populationsizeunlessthereisareproductivesurplus of females. In many cases, the environmental and management conditions do not allow for much reproductive surplus – especially in cattle, which have low reproductive rates. As such, most of the females that are raised must be retained as breeding animals in order to maintain the size of the population