F700
Ram Epididymitis (Brucella ovis)

Introduction: Ram epididymitis is a reproductive disease that causes inflammation of the epididymis in the male reproductive tract. The epididymis is the tubular portion of the testicle that collects the spermatozoa produced by the testicular tissues and stores it until transport when it is mixed with the seminal fluid to produce an ejaculate. Inflammation of the epididymis causes varying degrees of damage that can result in infertility and a reduced capacity to produce viable spermatozoa. Ram epididymitis is usually a condition of mature, sexually experienced rams. This disease is not recognized in goats. A serological survey (ELISA test) was recently conducted on 5,728 adult rams which had been exposed to multi-sire breeding systems. Out of the 5,728 rams, 20% were positive, 5% suspects, and 75% were negative. Individual flocks may experience infection rates as high as 50%.

Treatment/Prevention: Antibiotic treatment of B. ovis is disappointing because about half the cases will not respond, and many animals continue to have decreased fertility. Prevention is based on eradicating the disease from an infected flock and purchasing disease free rams. A producer should purchase only "virgin" yearling lambs that have a negative ELISA test or are from flocks that are free of B. ovis.

Eradication Procedures: Sheep producers can now rid their flocks of ram epididymitis. The process is very time consuming, but can be rewarding if done thoroughly and properly. Documented field studies have shown that control of ram epididymitis results in a shortened lambing period, an increased twinning rate, and a reduction in the percent of dry ewes. All this is accomplished while using fewer rams. The costs of an eradication program include culling of positive rams, veterinary/lab fees for blood collection/testing, and labor. Although culling of positive testing (carrier) rams is necessary, the program is still economically feasible for most producers. The majority of rams to be culled have reduced semen quality and often serve as more of an interference than an asset to the flock. Producers interested in cleaning up their flocks should plan on at least 2-3 years of intense management and annual testing, thereafter. Quitting too soon could result in the loss of any gains achieved during the eradication efforts. For eradication, the following steps should be taken:

1. Isolate the Rams Used for Breeding: Rams must be kept separate from rams of other flocks or the B. ovis organism will likely be re-introduced. Ewes should not be placed with the ram battery. Keep them separate except during breeding.
   
   
2. Palpate, Blood Test, and Cull Positive (and "Suspect") Rams: Rams with definite palpable lesions in the testicles should be culled. These animals do not need to be blood tested. Any rams with just suspicious lesions should be retained and be blood tested. All remaining rams in the breeding flock should be ELISA tested at 45-60 days following the breeding season. All positive rams should be culled, and further tests should be done on the remaining rams at 60-day intervals until two negative battery tests are achieved. Vaccination with the "REO" (Ram Epididymitis Organism) vaccine will interfere with the ELISA test and is not recommended. Because the lab results may not be available for 2-4 weeks, rams must be individually identified (good ear tag). The serum for the ELISA test must be separated from the blood samples soon after it is collected. The samples must also be handled carefully to avoid excessive hemolysis (cell breakdown) and false results. Once the flock is clean, annual palpations and blood tests must be conducted for a minimum of 1 year more. Annual testing is recommended, thereafter, for producers wanting to ensure continued detection of any new carriers.
   
   It may also be possible to clean up the battery by testing rams just at pre-breeding and post-breeding. However, because this option allows more time for transmission of disease to occur, it will probably require a longer total time for eradication.
   
   If a ram is especially valuable genetically but is affected with epididymitis, a plan may be devised to use him to breed some ewes. Be cautious that his use does not contribute to maintaining a B. ovis infection in the flock and that the ewes he breeds actually become pregnant. This will require separation, semen testing, harness marking, follow-up breeding, etc. In most cases, the ram must be extremely valuable to justify the extra trouble and potential complications.
   
   
3. Culling: It is important to recognize that there are very few completely sterile rams infected with B. ovis. Because of this, even those rams with lesions of epididymitis may produce a reasonable lamb crop. The primary value of culling infected rams is to remove the carriers of B. ovis. This removes potential sources for additional infection and stops the cycle. There may be some situations where it would be easier and cheaper in the long run to dispose of the entire ram battery and replace them with new virgin rams. This method of eradication may be chosen when there is a high rate of infection (50% or higher), when many of the rams are older, and when the producer is not set up to handle the repeated blood testing that is often necessary.
   
   
4. Protect Clean Rams: Do not mix clean rams with other rams from any untested flocks. Purchase only virgin rams that have never been used for breeding or mixed with older rams. As a precaution, have these virgin rams tested before mixing them with the clean ram flock.
   
   
5. Semen Evaluation: Most carrier rams (75%) can be identified from a semen exam because they will have reduced semen quality. Large numbers of white blood cells and/or separated sperm heads are often identified in the semen. A small proportion (10%) of rams will have reduced fertility even though they are not infected with epididymitis. The semen evaluation can be used to identify and cull these rams and to compliment the blood test results.
   
   
6. Breeding Ratio: Using only rams with good quality semen will allow a lower ram to ewe ratio. This may mean that every ram culled because of epididymitis does not have to be replaced. Most producers plan to have 3-4% of their flock be breeding rams. Field trials using semen tested rams that are B. ovis free have shown that 1.5 - 2% is often adequate. Any changes to the ram to ewe ratio should be implemented cautiously and be based on producer experience and specific flock conditions.