Dept. Theriogenology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
Transrectal palpation is the most common and the more cheaper technique used for examination of the physiological and pathological conditions of the bovine genital tract. However, in certain occasion this technique could not provide sufficient information (Grunert, 1979, Stolla and Himmer, 1980, Max, et al. 1997). Also, due to the anatomical features of the ewe, transrectal palpation is of no value in the investigation of genital tract of this species.
During the early of its application in veterinary practice, ultrasonography was used mainly for the assessment of normal morphological features of the reproductive tract (Pierson and Ginther, 1984, Kahn, 1985). Serving as a reliable instrument for pregnancy diagnosis and the examination of ovarian follicles and corpora lutea, its usage spread rapidly. Pathological phenomena were usually incidental findings and were considered under the aspect of differentiating them from physiological characteristics. Since then, increasing attention has been directed towards its usage in the diagnosis of pathological conditions of the uterus and ovaries (Fissore, et al., 1986, Kahn and Leidl, 1989).
This article deals with the echogenic characteristics of the most common clinically relevant disorders in the uterus of cattle and sheep, especially that of the Egyptian native breeds. Moreover, comparison between transrectal and ultrasonic findings were investigated.
MATERIAL AND METHODS
Animals included in this study were examined either during a routine gynaecological investigation, during pregnancy diagnosis, or during investigation some of infertility or obstetrical problems. Egyptian native (n = 15), Friesian (n = 20) and cross breed (Native x Friesian, n = 15) cows and heifers and native Osemi ewes (n = 43) were included in this study. They were examined at the veterinary medical teaching hospital of Assiut university, the veterinary service center-Riefa of Assiut Governorate, the agriculture farm of Assiut university and some villages of Assiut Governorate.
The cattle were firstly examined transrectally, followed by ultrasonic examination. The ultrasound examination was performed using a real time B-mode 6/8 MHz changeable linear array transducers (Pie Medica, 100 LC). The transducer was located over the required organ with a little bit movement from one side to the other to obtain a full information of the examined organ. Dimensions of the examined structures were obtained on a fixed screen of the scanner.
Ewes were examined with the ultrasound both transrectally and abdominally. Transrectal ultrasound examination was done as in cattle in a standing position, however only the transducer probe with one finger passed through the rectum. Abdominal ultrasound examination was performed in the wool-free area between the right inguinal fold and the udder.
Out of the examined animals, pyometra was recorded in 2 cows and in one ewe, hydrometra in one cow and in one ewe, fetal death in one heifer, fetal resorption in one ewe, embryonic death in one ewe and endometritis in 12 cows and heifers. The following are the history, transrectal and ultrasonic characteristics of the recorded cases:
1. Postcoital pyometra in a cow
A 4 years cross-bred cow was submitted in the clinic for pregnancy diagnosis three months after mating. Rectal palpation revealed a large sized uterus comparable to the mating date, however the uterine wall was thick. Fetal membrane slip, placentomes and fetal balottment were absent. Sonographically, the uterus was greatly dilated, folded and filled with an echogenic thick content (fig. 1). The echogencity of uterine content was more higher than that of the uterus. This case was injected with Prostaglandin F2a (0.750 mg tiaprostâ , i.m.) One day after the injection, a copious amount of purulant vaginal discharge started to escape. The purulant vaginal discharge continued for 3 successive days. On the last day, the animal showed clear vaginal discharge. Post-treatment sonographic examination revealed a smaller uterus which resembled that of the non-pregnant animals. This cows conceived after the elapse of two successive cycles.
2. Postpatum pyometra associated with cervicitis, vagnitis and cystitis in a cow
A cross-bred 3 years pluriparous native cow was submitted to the clinic 21 days after abnormal parturition. The vulva lips were necrotic. The cow arched her back and urinated frequently. The urine and vaginal discharge were mixed with threads of fibrin. Rectal examination revealed a moderate enlarged uterus and cervix. Ultrasonographically, the uterus was dilated with a thick echogenic content (fig. 2). The lining epithelium of the uterus represented highly echogenic spots, sloughed in some localities into the uterine lumen (fig. 3). The cervix and vagina were filled with hypoechogenic fluid tinged with some hyperechogenic flaky reflection of particles (fig. 4,5). Vaginal epithelium and that of the urinary bladder sloughed into their lumen (fig. 5,6).
This cow was treated with systemic antibiotic and local irrigation of the uterus with lotagen solution 4%. Examination of the cow one week later revealed slightly improvement in the condition of uterus. A single dose of Prostaglandin F2a (0.750 mg tiaprostâ ) was injected intramuscular. Examination after one week revealed a significant improvement of the genital tract.
3. Hydrometra in a cow
A seven years native-bred cow submitted to the clinic with a history of abnormal pregnancy. The cow was mated since five months. Attached examination report from the regional veterinary service suspected that the case is a mummified fetus as tentative diagnosis according to the rectal findings. Rectal examination revealed hard irregular masses of different sizes, from the size of an egg to big potatoe, were palpated in the pelvic and caudal part of abdominal cavities. The uterus was difficult to palpate. Ultrasonic rectal examination revealed many irregular and sometimes elliptical gray masses in the pelvic and the caudal abdominal cavities (fig. 7). Such masses were found clearly outside the uterus. The uterus was located in the caudal part of the abdominal cavity, filled with clear hypoecogenic fluid (dark), without placentomes or fetal membranes or fetus (fig 7). The animal was discarded from breeding.
4. Fetal death in a heifer
A Friesian heifer was submitted to the clinic to test the viability of her fetus. The heifer was inseminated for 8 months ago, however the abdominal circumference and the udder were not enlarged as expected. Transrectally, the uterus was partially in the pelvic cavity comparable to 3 months pregnancy. The right horn was the larger one and was not freely movable but adhered to the surrounding tissues. Sonographic examination showed a bony structure of an inert fetus in the ventral part of the gravid horn (fig. 8). This fetus did not show any internal organs. Less echogenic areas, as displayed by the fetal fluids suspending the fetus. Estimation its CRL indicating that this fetus died at the age of 75 days. The heifer was discarded from breeding.
5. Endometritis in cows and heifers
Inflammation of the uterus was recorded in 12 cows and heifers of different breeds. Such cases failed to conceived inspite of insemination/mating for more than two consecutive times. In most cases transrectal examination failed to reveal a palpable pathological finding, however, estral mucus in most cases was tinged with purulant flakes. Sonographic examination revealed in some cases an accumulation of hypoecogenic fluid in the uterine lumen . In other cases bright white image was observed within the uterus. Two regimes of treatment were applied. Half of the cases were treated with a single dose of prostaglandin F2a (0.750 mg tiaprostâ ) injected intramusculary, followed by a sexual rest for two cycles. Uterus of the other half of animals was irrigated with 4% lotagen solution. However, evaluation the efficient of treatments was difficult, due to some problems to follow up these cases.
6. Pyometra in a ewe
A ewe was examined before slaughtering to exclude the possibility of pregnancy. Ultrasound revealed the accumulation of an echogenic thick material within the uterine lumen, however no fetal parts or placentomes could be observed (fig 9). An extra x-ray examination on the uterus could not show any bony structures within the uterus. After slaughtering, the uterus showed collection of thick purulant material.
7. Hydrometra in a ewe
Hydrometra was observed in one ewe. This case was discovered during a routine gynaecological examination in a herd of ewes. The ewe was not inseminated or mated before. Ultrasonography revealed enlarged uterus with hypoecogenic fluid. No fetal parts or placentomes were visible and only fluid-filled compartments, separated by thin tissue walls, were observed (fig. 11). There was no any vaginal discharge. Examination of the ewe three times at a week interval revealed nearly the same ultrasonic picture with little reduction of the fetal fluid. Later on (after 5 months, fig. 12), the uterus was reduced in size and the fetal fluid completely diminished without treatment.
8. Embryonic loss in a ewe
This case was diagnosed as pregnant 35 days after mating. On the second examination 2 weeks later, the fetus could not be detected. However, the uterus was enlarged with hypoecogenic fluid tinged with many hpyerechogenic flakes (fig 10). Threads of the fetal membranes could be observed floating in the fetal fluid. This picture persisted for few weeks till the uterus returned to its normal nonpregnant status.
Ultrasound technique has been widely used in the examination of the physiological conditions of the female genital tract. It provides a safe, non-invasive method for direct visualization of ovaries, uterus and conceptus. Recently, sonography has shown to be equally efficient in the evaluation of some of the pathological conditions of the female genital tract.
Pyometra is characterized by large quantities of fluid often greatly dilating the uterus. The degree of echogenity depended on the consistency of the pyometral fluid. When the uterine contents were very thick and full of leucocytes and tissue debris, the echogenity closely resembled that of the uterine wall. With this respect the ultrasound examination confirmed the rectal finding and helped to reach the accurate diagnosis and the correct treatment. Also, PGF2a seemed to be an efficient and ideal treatment for the cases of pyometra, as the animal conceived shortly after treatment. This is in agreement with Gustafsson (1980).
Hydrometra is characterized by dilatation of the uterus with a large amounts of clear and hypoecogenic fluid, resembling to a great extend the finding of normal pregnancy. However, hydrometra is characterized by absence of the placentomes, the fetal membrane and the fetus. In such cases ultrasound examination might be essential to differentiate precisely between normal pregnancy and hydrometra. The solid objects located in the abdominal cavity might be a case of abdominal fat necrosis, as such case was diagnosed frequently in the same breed and in the locality (El-Sebaie and Hofmann, 1988).
Kahn and Leidel (1989) recorded that, the fetus is not immediately aborted after death. Repeated ultrasound scans revealed a steady reduction in the placental fluids. Furthermore, the anatomy of the fetal organs change. Structures which are very distinct in the living fetus become blurred or obscure after death. This is especially true for soft organs which undergo rapid postmortem changes (Staudach, 1986). Ossified structures, such as bone, being hyper-reflective, do remain detectable for some time. Fetal echoes within the uterus have been scanned successfully several weeks after death, when all the placental fluids had been resorbed (Ginther et al. 1985). In the present work, Except the skeletal system of the fetus, no fetal organs or parts of the fetal body were identifiable after fetal death. Concerning this subject, rectal palpation could not approach the appropriate diagnosis and a further ultrasonic investigation seemed to be essential.
The most apparent sonographic indication of endometritis is the unexpected accumulation of fluids in the uterine lumen. The amount of the secretions varies greatly depending on the severity of the condition. An important factor of consideration is the stage of the estrous cycle. Collection of the fluid can occur physiologically during normal estrus and during early pregnancy (Pierson and Ginther, 1987). Therefore, only if such fluid was encountered during diestrous, it is justified to be considered of pathological origin. In mild cases no uterine fluid, or nearly a few fluid-filled pocket will be found on scanning of the uterus. Severed endometritis is characterized by the presence slight amount of fluids. The echogenic patterns displayed by the products of inflammation range from small fluid collection in mild cases to an almost bright white images in sever cases. Kahn and Leidel (1989) stated that, the usefulness of transrectal ultrasound technology for the diagnosis of endometritis depends on the degree of pathological changes. When only small collection of fluid were present, diagnosis was often not possible. On the other hand, severed cases causing the entire uterus to become distended were easily recognized. However, a highly positive correlation was found between ultrasound findings and endometrial histopathology in post-menopausal women (Nasri and Coats, 1989).
Ultrasonography seemed to be the ideal and the more accurate technique for the visualization of the genital tract in the ewes, due to impossibility of transrectal palpation. The literature which deal with the ultrasonic pictures of the pathological conditions of the genital tract of small ruminants is scanty.
Pyometra in ewes resemble ultrasonographlly to a large extend that of cattle.
The ultrasonic appearance of hydrometra and of early pregnancy in ewes might be similar. To differentiate them from each other, in hydrometra no fetal parts and placentomes are present and only fluid-filled compartments, separated by thin tissue walls are observed. These thin tissue walls are formed by the fluid filled uterine horns curving under the corpus uteri (Lavoir and Taverne, 1989). The ultrasound picture shows various sections through these curved uterine horns. The ultrasound technology is the only way to diagnose such cases. A high incidence of hydrometra (6.9%) was diagnosed in a flock of ewes in USA (Bretzlaff, 1993). The author claimed that ultrasound examined might induced the condition.? Kornalijnslijper et al. (1997) induced hydrometra in a group of goats by their immunization against PGF2a.
The first indications of embryonic loss are the small-for-date size of embryo and decreased fluid of the conceptus (Kahn and Leidel, 1989). Conclusive evidence for the death is provided by the cessation of heart activity. With progression of resorption, the amount of placental fluids gradually decreased and their echogenity increased. The flaky reflections observed in the initial stages of embryonic loss intensified to give a snow-storm effect.
In conclusion it can be said that transrectal ultrasound scanning is a valuable method of diagnosing pathological conditions of the uterus in cattle and sheep. In some cases it gives supplementary evidence when classical methods such as transrectal palpation cannot provide sufficient information.
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Fig. 1 Post-coital pyometra in a cow: Longitudinal section in the uterine horn revealed collection of an echogenic purulant exudate within the uterus. The uterus greatly dilated and folded on the accumulated pus.
Fig. 2 Post-partum pyometra in a cow:
Sagital-section in uterine horn showing accumulation of an intensive echogenic purulant material.
Fig. 3 Post-partum pyometra in a cow: Cross-section in the uterus showing accumulation of an echogenic purulant material and a highly echogenic sloughed endometrial tissue.
Fig. 4 Cervicitis in a cow: Collection of hypoechogenic
fluid between cervical rings.
Fig. 5 Vaginitis in a cow: accumulation of less echogenic fluid and highly echogenic irregular sloughed tissue in the vagina.
Fig. 6 Cystitis in a cow: the urinary bladder contained many tissue debris and sloughed material. The echo patterns of the content show a snow-storm effect.
Fig. 7 Hydrometra in a cow: the uterus dilated with a clear hypoechogenic fluid. There was no placentmoes, fetal membranes or fetus. The uterus extended to the abdominal cavity. Many solid, irregular echogenic objects were detected in abdominal cavity.
Fig. 8 Fetal death in a heifer: Only skull and ribs of the fetus could be observed. The internal organs were completely absent The fetal fluid changed to give a snow-storm effect.
Fig 9. Pyometra in a ewe: The uterus dilated with a less echogenic purulant material.
Fig10. Embryonic death in a ewe: Embryo could not be detected after a previous positive diagnosis. The fetal membranes degenerated and floated in the fetal fluid.
The fetal fluid reduced and gave a cloudy appearance.
Fig. 11 Hydrometra in an ewe: fluid-filled compartments, separated by thin tissue walls are observed. Fetus, fetal membranes and placentomes were absent.
Fig. 12 The same uterus of fig. 11 after 5 months. Spontaneous reduction of the accumulated fluid.