Observation Of Uterine Involution In Etawa Crossbreed Goats (Capra hircus) Using Transcutaneus Ultrasonography Observasi Involusi Uterus pada Kambing Peranakan Etawa (Capra hircus) Menggunakan Ultrasonografi (USG) Transkutaneus

The aim of this study was to observe the uterine involution of Etawa crossbreed goats using transcutaneous ultrasonography (USG). This study used four postpartum female goats that released placenta normally. The goats were examined on lateral recumbence position. Uterine involution was observed daily. The study began from the first day of postpartum period until there were no more reduction of uterine horns lumen diameter. From the 1st to 7th day of postpartum period, ultrasound imaging of the uterine wall showed caruncle which was hypoechoic, lumen of uterine filled with lochia (the image was hypoechoic to anechoic) and a clearly visible uterine horns lumen which had decreased in diameter from 105.9 ± 0.9 mm to 87.2 ± 4.6 mm. From the 8th day to the 14th day, lumen diameter had decreased from 80.4 ± 3.8 mm to 63.6 ± 3.2 mm. The presence of caruncle was reduced and


Introduction
Postpartum uterine involution has a profound effect on reproductive and economic interests in order to determine the optimal timing of subsequent pregnancies 1 (Sanchez et al., 2002). During the postpartum period, the reproductive system returns to normal function and prepares itself for a new pregnancy (Elsheikh et al., 2013). Uterine involution is the reduction of uterine volume from pregnancy size to normal size of the uterus before pregnancy. In this reduction process, the following processes also occur: regeneration of the endometrial epithelium, reduction of myometrial tendon fibers, and reduction of uterine blood vessels. The maternal placenta experiences involution through necrosis of caruncle cord due to vasoconstriction, leukocyte infiltration and caruncle removal due to fat infiltration, dissolution, drainage and decay of the entire caruncle surface that becomes lochia (Gier and Marion, 1968). Uterine involution is needed to prepare for a new pregnancy. The time needed to complete the uterine involution macroscopically in sheep varies between 17-30 days (Van Wyck et al., 1972), whereas uterine involution in Kacang goat (Capra hircus) is completed on the 20th day, which is marked by the stabilization in size of the diameter of uterine horns lumen (Riady et al., 2015).
According to Call et al. (1976), it is difficult to assess the time of uterine involution in goats, because the uterus cannot be examined by rectal palpation. Most studies of uterine involution were examined surgically or by laparotomy 7 (Rubianes et al., 1996). According to Goel and Agrawal (1992), several techniques such as laparotomy, laparoscopy, and radiography, which were used to study various stages and changes in uterine morphology in ruminants, had many disadvantages. Its application in this field has surgical risks, radiation hazards, requires certain expertise or specific laboratory requirements. The dynamic aspects of morphological changes are largely inaccessible, while ultrasound provides non-invasive techniques that do not interfere with organs (Griffin and Ginther, 1992). Ultrasound is routinely used for the diagnosis of pregnancy in goats (Buckrell, 1988). Examination of pregnancy with ultrasound can be carried out in two different methods, namely transrectal and transcutaneous, depending on the method of diagnosis, type of ultrasound probe available, and conditions on the ground at the time of examination (Kahn, 2004). In addition, Hauser and Bostedt (2002) proved that transrectal ultrasonography was a useful and reliable method for observing uterine involution in sheep.
This study aimed to describe the uterine involution of Etawa crossbreed (PE) goat using transcutaneous ultrasonography. The benefit of this study was expected to provide information about the description of uterine involution of Etawa crossbreed (PE) goats.

Materials and Methods
This study used four postpartum female goats which delivered their placenta normally. Female goats were kept in separate cages with male goats and were allowed to breastfeed their lambs. Observations were made using ultrasound (DP3300 MINDRAY, Shenzen Mindray Bio-Medical Electronic Co. Ltd, China) with 3.5 MHz abdominal probes (35C50EB, Shenzen Mindray Bio-Medical Electronic Co. Ltd, China) in PE goats since the first day of postpartum period. Observation of uterine involution stopped after the amount of lochia was decreased (anechoic). From the 15 th day to the 21 st day, lumen diameter had decreased from 61.4 ± 2.1 mm to 52.1 ± 2.7 mm, and the remnants of caruncle and lochia were still visible. From the 22 nd day to the 26 th day, the diameter of the uterine wall had decreased from 49.7 ± 0.6 mm to 41.5 ± 6.7 mm, and the lochia and caruncle were no longer visible. From the 26 th to the 30 th day, uterine horns lumen diameter had still decreased from 41.5 ± 6.7 mm to 31.7 ± 0.9 mm. Uterine horns lumen diameter size had decreased every day, stabilized on the 30 th day, and ceased to decrease on the 31 st day, where the diameter size was the same as on the 30 th day postpartum (31.7 ± 0.9 mm). It can be concluded that the duration of uterine involution in PE goats, which had normal delivery is 30-31 days.
Key words: PE goat; ultrasonography; uterine involution there was no longer a reduction in the diameter of uterine lumen.

Observation of Uterine Involution with Transcutaneous Ultrasound
Observation of uterine involution using transcutaneous ultrasound started from the first day of postpartum period. Goat were observed at the same hour every day. For the initial step, an ultrasound device was prepared, then the ultrasound was placed to the left of the operator's arm and the operator was on the left side of the goat. Observation of uterine involution using transcutaneous ultrasound was performed after the goat was laid in a lateral recumbence position. Some hair in the abdominal area was shaved before the evaluation in order to acquire the best visualization of the image in this area.
The next step was the application of KY jelly around the abdomen. The probe was gently pressed on the abdomen towards urinary bladder, then it was directed to cranially to the mammary glands and to the base of the hind leg. Afterwards, the ultrasound device was directed to the dorsal and slightly caudomedial, followed by measurement of the lumen diameter of the uterine horns. Ultrasound images were taken with the freeze button and then the diameter of uterine horns lumen was measured. After the observation was completed, the abdomen was cleaned of the excess KY jelly. Observation was stopped and involution was said to be complete after there was no longer a reduction in uterine lumen diameter.

Data Analysis
The results of observation of uterine involution were analyzed descriptively and presented in several images.

Results and Discussion
On the first day until the 7 th day of postpartum period, the uterine horns images were almost identical, and the diameter of the uterine horns lumen consistently decreased every day from 105.9±0.9 mm to 87.2±4.6 mm. Examination of postpartum uterus on the first day clearly showed the caruncle, the uterine lumen, and the uterine wall appearances. The appearance of caruncles on the uterine wall from ultrasound examination was hypoechoic (gray), while the lumen of the uterus, which was filled with lochia was hypoechoic to anechoic ( Figure 1). These ultrasound images of postpartum uterine (H-1 to H-7) in PE goats were almost the same as images which were reported by Riady et al. (2015) in Kacang goats. The images showed that caruncle was hypoechoic and anechoic in the center, lochia was anechoic, and the blood vessel layer was anechoic which limits the endometrium (hypoechoic) to the myometrium (hypoechoic). According to Ababneh and Degefa (2005) in Balady goats, observation of uterine involution using transcutaneous ultrasound on the first and second days of postpartum period showed caruncles, myometrial and endometrial layers separated clearly by anechoic lines, and anechoic lochia in the uterine lumen.
Uterine involution occurs on a reduced logarithmic scale with the most significant changes occurs during the first days postpartum. Uterine contractions last for several days, during which the amount of lochia is reduced and followed by a reduction of the uterine lumen (Noakes, 2009). This finding was supported by a study by Degefa et al. (2006) which found that uterine involution in Balady goats was divided into three stages: the 1). most rapid decline occurred until the 7 th day, the regression stage occurred until the 13 th day, and uterine involution was completed on the 19 th day of postpartum period. The results of a study by Ababneh and Degefa (2005) also proved that the decrease in uterine volume was significantly faster until the 7 th day of postpartum period compared to the 7 th to 19 th day of postpartum period. According to Hauser and Bostedt (2002), uterine regression is completed around 17-19 days postpartum based on a research conducted on sheep.
The diameter of uterine horns lumen on the 8 th day was 80.4±3.8 mm, which was decreased daily to 63.6±3.2 mm on the 14 th day of postpartum period as presented in Figure 2. Hauser and Bostedt (2002) also stated that ultrasound could accurately distinguish and measure the caruncles only until the 8 th day of postpartum period. Fasulkov (2012) stated that on the 9 th day of postpartum period, only the thickness of the uterine wall that could be measured using transcutaneous ultrasound. Uterine involution in small ruminants were characterized by a reduction in the size and the presence of rapid uterine contractions as showed by measurements of uterine weight and length, lumen diameter, and diameter of uterine horns of pregnant animals (Noakes, 2009). uterus namely the endometrium and myometrium while the perimetrium layer was not seen. Hauser and Bostedt (2002) reported that perimetrium and myometrium exhibit the same echoic structure (image) so it was impossible to distinguish them from ultrasound observations. The vascular layer, which was located in the myometrial layer, was a sign of high vascularization. This anechoic vascular layer can be seen as a black line in the cross-section. From the 15 th to the 21 st day, ultrasound images showed that the lumen of the uterine horns, the remnants of caruncle, and the lochia began to become less obvious by the 21 st day. The diameter of uterine horns lumen on the 15 th day was 61.4±2.1 mm which had decreased to a size of 52.1±2.7 mm by the 21 st day, as presented in Figure 3. In this study, the images only showed two layers of the  After the offspring is born, the uterus, which experiences contraction and retraction during pregnancy, becomes hard so it could close large blood vessels, which lead to placental implantation site (Sarwono, 2002). Uterine involution is an autolysis process or a self-destruction process that occurs in the uterine muscle, the tissue, which undergoes proliferation in the presence of large amounts of estrogen. It then undergoes atrophy as a response to the cessation of estrogen production, which accompanies the release of the placenta. The effect of oxytocin hormone release from pituitary gland strengthens and regulates uterine contractions, compresses blood vessels, and helps the hemostasis process. The contraction and retraction of uterine muscle reduces the blood supply to the uterus. This process helps reduce the scar where the placenta was implanted and reduces bleeding (Sarwono, 2008).
Uterine involution is highly dependent on myometrial contraction, bacterial elimination, and regression of the endometrium. These three things are related to each other. The myometrium is a collection of smooth muscle cells and collagen fibers that will contract regularly under the influence of the estrogen, prostaglandin, and oxytocin hormones during postpartum period. This process results in shortening of longitudinal and circular myometrial fibers, followed by involution of caruncle and endometrial regeneration. Factors that influence uterine involution are breastfeeding, quality and quantity of feed, and hormonal activity. The longer the period of breastfeed, the lower the quality and quantity of feed. Additionally, the lack of hormonal stimulation, especially prostaglandins, prolongs uterine involution and consequently the interval of breeding will be longer (Jainudeen and Hafez, 1993).
From the 26 th to the 30 th day, the ultrasound images of the uterus only show the lumen of the uterine horns, whereas the caruncle, uterine wall layer, vascular layer, and lochia were not seen. The average diameter of uterine horns lumen on the 26 th day was 41.5±6.7 mm, which had decreased to 31.7±0.9 mm by the 30 th day. On the 30 th and 31 st day of postpartum period, the diameter of the uterus lumen remained at 31.7±0.9 mm and the observation of uterine involution was stopped. This was in accordance with a study by Ababneh and Defega (2005), which found that in Balady goat, involution was completed after there was no longer reduction in the diameter of the uterine horns lumen. Uterine ultrasound features of PE goats on the 30 th and 31 st day are shown in Figure 5.
Endometrial and myometrial features were poorly differentiated using transcutaneous ultrasound because the diameter of uterine is fixed, same as before pregnant. This imaging is different from the appearance of a pregnant goat uterine. In previous research Melia et al. (2018) reported, the uterus of non-pregnant Etawa crossbred goat showed isoechogenic uterus lumen, no hypoechogenic appearance from embryonic vesicle and no image of isoechogenic embryo as early indication of diagnosing pregnancy. The time required for uterine involution varies according to the type of animal, reproductive status, and time of observation (Jainudeen and Hafez, 1993). Most of the studies found that uterine involution is completed around 17-19 days postpartum (Hauser and Bostedt, 2002;Ababneh and Degefa, 2005). In Kacang goats, uterine involution is completed on the 20 th day of postpartum with a diameter of 19.3 mm 5 . Another technique used to observe the process of uterine involution in small ruminants is the measurement of hormone and its metabolites, radiography, and laparotomy. In this study, there were three goats with single gestation and one goat with multiple gestations. The measurements of uterine horns diameter and the duration to complete uterine involution were similar in goats with multiple gestation and single gestation.

Conclusion
Ultrasonography of uterine involution in PE goats showed caruncles and lochia were present until the 21 st day of postpartum period. There was a daily decrease in the diameter of the uterine horns lumen from 105.9±0.9 mm on the first day to 31.7±0.9 mm on the 31 st day of postpartum period. The process of uterine involution in PE goats, which had normal delivery lasted for 30-31 days.