Pseudopregnancy in goats most often affects older, multiparous does. The primary clinical sign is hydrometra (accumulation of fluid in the uterus). The condition can be diagnosed by ultrasonography or by measuring low concentrations of pregnancy-associated glycoprotein. Treatment is to administer prostaglandin F2alpha or an analogue to induce luteal regression and discharge of the uterine fluid.
Pseudopregnancy is an accumulation of aseptic fluid in the uterine lumen devoid of a viable conceptus in the presence of a persistent corpus luteum. Pseudopregnancy can occur in all ruminants; however, it is most common in goats. It is one of the major causes of anestrus in goats during the breeding season.
Etiology and Pathogenesis of Pseudopregnancy in Goats
The etiology of pseudopregnancy is poorly understood. The following factors have been suggested as reasons for this condition:
decreased production or release of prostaglandin F2alpha (PGF2alpha) from the endometrium
exposure to phytoestrogens
early fetal death with subsequent fetal resorption and a persistent corpus luteum, in does that have been bred
Other reasons for pseudopregnancy may include out-of-season breeding, excessive hormonal manipulation of the reproductive cycle, and congenital malformations of the cervix and uterus.
Epidemiology of Pseudopregnancy in Goats
The incidence of pseudopregnancy in goats varies; it has been reported between 6% and 30%. Pseudopregnancy occurs most commonly in pet and dairy goats, which experience estrous cycles with no opportunity to be bred. It has also been shown that hydrometra, the primary clinical sign, is more prevalent in older does.
Clinical Findings of Pseudopregnancy in Goats
Most cases of pseudopregnancy in goats present in adult females that are not being bred (thus they experience persistent anestrus with elevated progesterone concentration).
If hydrometra (accumulation of fluid in the uterus) is present, there may be bilateral abdominal distention (see hydrometra photograph). Hydrometra is the primary clinical sign of pseudopregnancy. It develops during prolonged and continuous exposure to progesterone from the corpus luteum.
When not diagnosed, pseudopregnancy can persist for up to several months, and the amount of fluid can reach a volume of several liters. In such cases, the distended abdomen will give the false impression that the doe is pregnant; abdominal distention can also be accompanied by udder enlargement and spurious lactation.
Courtesy of Dr. Marcel Taverne.
Diagnosis of Pseudopregnancy in Goats
Hormone analysis
Ultrasonographic examination
Differential diagnoses of pseudopregnancy include pregnancy, mucometra, pyometra, and pituitary adenoma.
Standard blood work (CBC, biochemistry, and urinalysis) will not rule out a true pregnancy. However, if available, hormone analysis of progesterone (to confirm the presence of a corpus luteum) and/or of estrone sulfate may prove useful. A test for estrone sulfate (blood or urine) should be negative with pseudopregnancy.
Pseudopregnancy can be diagnosed via ultrasonography, which will show a large, fluid-filled uterus with no cardinal signs of pregnancy, of placentomes, or of a fetus (see ultrasonographic hydrometra image). When an abundant amount of fluid is present, these tissue layers can be observed undulating when the examiner shakes the abdominal wall of the doe.
Courtesy of Dr. Jamie Stewart.
During an early ultrasonographic pregnancy diagnosis (20–30 days after breeding or insemination), it can be difficult to discriminate between normal pregnancy and hydrometra because the embryo or placentomes can be difficult to locate at this stage, and excess fluid may be mistaken for allantoic fluid. After day 30 of postmating anestrus, low concentrations of pregnancy-associated glycoprotein in peripheral blood will confirm the absence of a viable conceptus in goats with or without hydrometra.
Treatment of Pseudopregnancy in Goats
The treatment of hydrometra is to empty the uterus, usually by administering PGF2alpha (or one of its synthetic analogues).
Recommended doses are as follows:
Dinoprost: 5 mg/goat, IM, repeated in 12 days (1)
Cloprostenol: 37.5 mcg/goat, IM, administered for a total of 3 doses 10 days apart (2)
Treatment with a luteolytic dose induces luteal regression and discharge of the uterine fluid within 1–2 days. In some patients, a second injection is required to achieve complete discharge of fluid from the uterus.
In one study, uterine fluid was totally drained in 50% of goats with hydrometra after one dose of PGF2alpha, and in 95% after two doses (2). Another study showed that a single dose of PGF2alpha is not a satisfactory treatment for hydrometra (57.9% efficiency in draining uterus contents, compared to 89.5% efficiency after a second dose) (3).
If treated during the breeding season, a pseudopregnant doe will come into estrus within 2–3 days and can be bred or inseminated again.
Pseudopregnancy also may end spontaneously when progesterone production by the (aging) corpus luteum stops. As a result, the cervix relaxes and uterine contractility is stimulated, and then the uterine fluid is discharged. This latter process has also been termed “cloudburst.”
The fertility of does appears to reach an acceptable rate (up to 55%) after effective treatment with prostaglandins; therefore, culling of affected goats is generally not necessary after pseudopregnancy.
Prognosis and Follow-Up
Patients with pseudopregnancy should be monitored until return to estrus has been observed. Risk factors for pseudopregnancy include phytoestrogen exposure, out-of-season breeding, and hormonal manipulation of the breeding cycle.
Possible complications of pseudopregnancy include pyometra and infertility.
Treatment of pseudopregnancy will hasten luteal regression; however, the corpus luteum can also regress spontaneously, with a return to normal fertility. Overall, a positive response to treatment results in a good prognosis for use and life.
Key Points
Pseudopregnancy is a major cause of anestrus in dairy goats.
Hydrometra is the primary clinical sign of pseudopregnancy and can be diagnosed via ultrasonography.
Treatment is multiple luteolytic doses of prostaglandin F2alpha or an analogue.
References
Hesselink JW. Hydrometra in dairy goats: reproductive performance after treatment with prostaglandins. Vet Rec. 1993;133(8):186-187. doi:10.1136/vr.133.8.186
Maia ALRS, Brandão FZ, Souza-Fabjan JMG, et al. Hydrometra in dairy goats: ultrasonic variables and therapeutic protocols evaluated during the reproductive season. Anim Reprod Sci. 2018;197:203-211. doi:10.1016/j.anireprosci.2018.08.030
Souza JMG, Maia ALRS, Brandão FZ, et al. Hormonal treatment of dairy goats affected by hydrometra associated or not with ovarian follicular cyst. Small Rumin Res. 2013;111(1-3):104-109. doi:10.1016/j.smallrumres.2012.10.003
For More Information
Pugh DG., Baird AN, Edmondson MA, Passler T. Sheep, Goat, and Cervid Medicine. e-Book. Elsevier Health Sciences; 2020.
