Sheep Industry News September 2025

Utilizing Teaser Rams

Jessy Shanks Extension Specialist

Teaser rams are utilized often in artificial insemination (AI) and embryo transfer (ET) programs because they can detect heat in females by marking them (if equipped with a ram harness or another form of marking paint). This way the veterinarian performing these procedures can be assured that the synchronization protocol worked and the females are indeed in heat prior to performing AI or ET. These programs can be successful without the use of a teaser ram, but most producers find them to be helpful when a teaser is detecting heat for you. A teaser ram is created by removing a section of the vas deferens to prevent sperm transport. This allows the teaser to act, smell and perform just like a fertile ram, but he is not capable of ejaculating sperm. It is important to note that the teaser will need time to heal from this relatively simple pro cedure, which is performed by a veterinarian under general anesthesia. He should be recovered and ready to work a few weeks before you actually need to use him. It is also worth mentioning that a quick semen check is beneficial to make sure the teaser is indeed shooting blanks and cannot get any females pregnant. That would be a bad day if your “teaser” was actually fertile and ended up breeding all your females who were set up for an AI or ET protocol!

Small Ruminant and Youth Programs University of Tennessee, Knoxville T easer rams have been in use for many years, but due to the increasing use of advanced reproductive tech nologies, such as artificial insemination and embryo transfer, they have become a topic of conversation among sheep producers. A teaser ram is a vasectomized male that still has his testicles, along with the accompanying hormones and attitude, but essentially shoots blanks when it comes to ejaculation. Why would this male be of any use to a sheep producer? There are a few reasons why they can be useful, but they may not work for everyone. Sheep are known for their seasonally polyestrous pattern of reproductive behavior, meaning they experience multiple es trous cycles during one season of the year. Sheep are primar ily short-day breeders, so this season is in the fall for most breeds, although there are a few exceptions. Due to their seasonality, sheep often start to cycle when daylight begins to decrease, but this can be hastened a bit by introducing a ram. We call this the “ram effect” which simply means that when a ram is introduced, usually a novel male that they have not seen before and have not had close contact with, females will start to cycle because they are stimulated by pheromones produced by the ram. It is important that the females are kept away from any male sheep for at least a month prior to this introduction in order for the ram effect to be stron gest, and yes this includes ram lambs. Once the novel ram is introduced some females will immediately start to cycle and some will start to cycle later, but these are often “silent heats” meaning they show no outward signs of being in heat. A teaser ram can help by stimulating ewes to come into heat and then actually mounting them. However, if the va sectomy was performed correctly, he will not be able to cause any pregnancies due to there being no sperm in his ejaculate. By introducing the teaser ram, the producer knows which females are cycling and the fertile ram does not have to do all this work to initiate cyclicity. Most research indicates that the fertile ram can be introduced 17–23 days after introduction of the teaser ram; then, the fertile ram can breed the females. In short, the teaser ram does all the work, but the fertile ram comes in and can hopefully provide a tighter breeding and lambing window.

September 2025 • Sheep Industry News • 13