By Brady Campbell
As many producers are in the midst of preparing for the upcoming breeding season, there are many tasks that need to be completed before turning the rams in. Of course, decisions need to be made regarding mating pairs and when to start flushing the ewes, but in this process have you ever considered "jump-starting" the cycling of your flock in preparation for breeding. With this, I have a few questions that I have to ask many of you. Have you ever introduced a teaser ram to allow your ewes start cycling and to shorten the breeding season? If you answered no, I’ll ask, why not?
A teaser ram is male that had a vasectomy, thus making the male sterile. Teaser rams are beneficial as they will stimulate your ewes to begin cycling without using your highly valued breeding rams, which greatly reduces the risk of them becoming injured or even sterile during the summer heat.
The reason that this practice works so well is due to the "ram effect." A teaser ram will still look, act, and even smell like a ram with the exception that it is no longer fertile. The presence of the ram is enough to result in the increase of luteinizing hormone (LH), which is critical for breeding as it triggers ovulation.
Additionally, it has been noted that small ruminants can go through a period where they may have a short heat cycle or "silent heat," which is a cycle in which the females are not able to become pregnant. This silent heat will occur within 3-5 days after introducing a ram and is typically induced by the ram effect. Following the silent heat, ewes will begin cycling normally. According to research conducted by the Queensland Government, it is expected that during the first true heart following the silent heat, approximately 60% to 70% of the ewes will conceive on their first cycle. During the second cycle, approximately 60% to 70% of the remaining ewes will conceive. This process also allows your ewe flock to become synchronized, allowing for shorter breeding and lambing periods. Additional data from Vet Services in New Zealand reported that 90% of ewes that were placed with teaser rams lambed within seven days of their scheduled due date (set according to the introduction of fertile breeding rams) as opposed to the ewes that were not placed with teaser rams in which only 15% lambed within seven days of their respective due date.
The many benefits of using a teaser ram include:
• maximizes conception rates
• reduces the work load (multiple mountings and breedings during silent and fertile heat cycles) of fertile breeding rams to reduce the instances of rams becoming injured or sterile during the summer heat
• in a pasture lambing situation, a teaser ram increases the effectiveness of predator control as lambs will be born during a specific time
• allows for producers to market lambs at a similar age and size
However, this system does not come without its flaws. The introduction of the ram effect with maiden ewes has shown to be inconsistent, and it’s unclear as to why. If ewes have already been previously exposed to the ram effect (fence line contact or rams being housed nearby where ewes can smell the rams) the use of a teaser ram has not shown much benefit.
In addition, for ewes that are difficult to breed or to begin cycling, the addition of a teaser ram may not benefit the producer.
If you’d like to give a teaser ram a try, here are some things to consider. First, you must choose the right ram. First and foremost, a teaser ram must be in good health. A teaser ram should have good teeth, feet, legs, and libido. Using mature rams (yearlings or older) is better, as ram lambs will demonstrate lower level of sexual activity when placed with mature ewes. Although, a ram lamb can be used for more breeding seasons when compared to mature rams.
When choosing what breed to use for a teaser ram, be sure to use rams with a high sex drive and will be sexually active out-of-season. Breeds that are recommended are Dorset, Finn, Suffolk and Hair sheep breeds, to mention a few.
When considering a teaser ram, be sure to plan well in advance. Make sure that you are able to source the appropriate ram, a veterinarian to perform the surgery and allow enough time for the ram to recover from the procedure. It is always a good practice to semen check your vasectomized rams once the procedure has been completed. Therefore, sourcing these rams should be done in the spring.
Now that you have your teaser ram selected and ready to go, how do you use it? Reports indicate that one mature and fit teaser ram should be enough to use on 50 to 100 ewes. Depending upon where you are receiving your information, literature from producers in the UK, Australia and New Zealand recommend placing the teaser ram with the ewes for about two weeks prior to breeding. In discussions with producers here in the U.S., it has been recommended that the teaser ram be placed with the ewes four weeks prior to breeding. However, this contradicts other shepherds around the world as they state that three weeks is too long. As you work through experimenting with your own flock, a general rule would be to leave your teaser ram with your ewes for two-to-four weeks. Again, as you begin to understand what works best for your operation, it will lead you in the right direction in appropriately using your teaser ram.
Although it may be too late for this breeding season to use a teaser ram in your operation, the thought of effectively and efficiently using your breeding rams and tightening the breeding and lambing windows is certainly something to be excited about. For those that are interested in how a teaser ram could benefit you and your operation, I encourage you to search the web and ask your fellow shepherds.
Campbell is the Program Coordinator of Ohio State University's Sheep Team.