This is usually performed on rams or bulls to ascertain if they are of reproductive value to your flock or herd for the coming breeding season. This is done by first performing a clinical examination, followed by a detailed fertility examination. This includes palpation and examination of the sex organs and the collection of semen. The semen will be evaluated for its viability and certain diseases can be tested for with certain samples taken from the animal. The vet can then certify that your animal is fertile which is sometimes necessary for the selling of the animals or for insurance purposes. The vet can only certify the fertility of the animal and can not guarantee offspring.