Hydrometra and pseudopregnancy
Keywords: caprine, goat, pseudopregnancy, hydrometraThis condition is occasionally reported in other animals but it is only in goats that it is common and fairly well characterized.
For unknown reasons, there is sudden cessation of luteolysis in the absence of pregnancy. It is usually noticed during the fall and winter when goats are normally having estrous cycles.
Clear, sterile fluid accumulates in the uterus; so clear that it resembles water (see below). This gives rise to the term "hydrometra". Also, because affected does are not cycling and the condition is frequently diagnosed when most does are pregnant, the condition is also known as ‘pseudopregnancy’.
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Fluid remains in the uterus for a variable period of time sustained by the presence of one or more corpora lutea; in this case, two. The progestogenic environment maintains uterine quiescence and closure of the the cervix. Up to ten liters of fluid accumulation has been reported in some cases yet uterine rupture has not been documented. After a variable period of time, spontaneous luteolysis occurs and the fluid is discharged. The lay term for this discharge is "cloud burst".
Usually, individual does are not presented for treatment for hydrometra. The author has encountered this condition in goats while performing ultrasound for pregnancy diagnosis. In such cases, it is easily diagnosed because does are usually tested for pregnancy when placentomes are well developed (> 90 days). In these cases, there are large amounts of fluid in the uterus but no placentomes and obviously, no fetuses.
Hydrometra is most prevalent in older does. The graph below shows the numbers of does in age categories (there are more young does than older does) but also shows that there is a relative increase in hydrometra cases as does age.
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In some herds, up to 20% of the does experience hydrometra; in others, the incidence is usually far lower. This has given rise to speculation that hydrometra may have a genetic basis but at this time, selective culling of affected does is not generally recommended.
Luteolytic doses of prostaglandin are curative but several treatments at 10 to 12 day intervals may be required in some cases. Apparently does should not be bred at the first induced estrus after treatment for hydrometra because fertility can be very low at that time.
Note: Images of hydrometra are not common because the condition does not affect long term fertility and does are seldom culled as a consequence. This case was a chance finding in a doe that was euthanized for an unrelated condition.
References:
Fatet, A. et al. 2011. Reproductive cycle of goats Animal Reprod. Sci. 124:211–219
Hesselink, J.W. 1993 Incidence of hydrometra in dairy goats. Vet. Record. 132: 110-112
