Ram Epididymitis
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%. Causative Agent: Although a variety of organisms and trauma can
cause inflammation of the epididymis, the cause of contagious ram
epididymitis in mature rams of multi-sire breeding systems is the
bacterium Brucella ovis (B. ovis.)Disease Transmission: A non-infected
ram picks up the disease by homosexual activities or during the
breeding season via the ewe. The B. ovis organism enters the blood
stream of the ram through the mucous membranes of the penis and
infects the reproductive tract and epididymis. The organism escapes
from an infected ram through urine or semen. The ewe, although not
permanently infected, plays a role in the mechanical
transmission.Clinical Signs: This infection causes inflammation and
scarring of the ram’s reproductive tract, which results in impaired
semen production and lowered semen quality. Enlargement and
fibrosis (scarring) of the epididymis with shrinking of the testicular
tissue is the classic clinical sign. In many cases, however, the infection
of the secondary sex organs (prostate, bulbourethral gland) occurs
without the epididymis being infected. These rams do not have lesions
that can be felt and must be identified by semen evaluation and
serology. In some cases, B. ovis infections in ewes can cause abortions
or death of newborn lambs .
Normal testicle Diseased testicle
Diagnosis: Diagnosis of B. ovis induced ram epididymitis is by palpation
of the testicle and epididymis for fibrotic lesions; however, this
method does not detect those animals with infection of the secondary
sex organs. These rams must be diagnosed by semen examination for
the presence of white blood cells (WBC) and spermatozoal
abnormalities. Both types B. ovis infections can be diagnosed by semen
culture or by serology. Currently, the enzyme linked immunosorbent
assay (ELISA) is being used for early detection of B. ovis
infectionsTreatment/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: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.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.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.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.
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.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 conditionsSummary of
Eradication Program Optionslan A: (Potential for rapid cleanup)Palpate
and blood test all rams every 2 months, until 2 negative flock tests are
obtained. An excellent time to begin is 1 to 2 months after the
breeding season. Cull all positive rams .alpate and blood test annually
for surveillance purposes .emen test all rams 1-2 months prebreeding.
(Optional )lan B: (May take several years)Palpate, blood test, and
semen test all rams prebreeding, and cull those that are positive on
any of the tests or have poor semen quality .Palpate and blood test
post-breeding .lan C:
Cull all resident rams .
Replace with virgin rams that have tested negative for B. ovis .
Lamb Epididymitis: Many ram producing (purebred) flocks are affected
with sporadic cases of epididymitis in the lamb or yearling rams being
raised for sale. These cases are usually not caused by the B. ovis
organism but by one of several other organisms instead. This needs to
be viewed as a completely different disease process, although the signs
of epididymitis are the same as those caused by B. ovis. The only
known ways for these rams to be infected with B. ovis are if they are
used for breeding in a range flock (leased or loaned out) or if they are
mixed with adult rams that are infected. The following
recommendations are to aid ram producers in reducing ram lamb and
yearling ram epididymitis:Separate: Separate non-castrated lambs
from each other and never mix them with adult rams. If any are used
for breeding, do not re-mix them back with the virgin rams .alpate:
Palpate all ram lambs every 1-2 months from weaning time until they
are sold. Remove all affected rams as soon as they Feeding: Feeding
low levels of antibiotic during the growing out period can reduce the
incidence of lamb epididymitis, especially at times of stress.