Use of Tubo-Ovarian Ligation Via Colpotomy as A Potential Method for Sterilization in Mares.

The goal of this study was to develop a safe, effective, and economical method for permanent sterilization of mares based upon tubo-ovarian ligation performed via colpotomy. In this study, we evaluated the application of a nylon cable tie (zip-tie) to the ovarian pedicle and oviduct of mares to induce ovarian ischemia and tubal ligation without removal of ovaries. Initially, efficiency of zip-ties on the ovarian pedicle was tested in vitro and in vivo. Based on the absence of leakage through the zip-tie ligated vessels in anatomic specimens, we confirmed the potential efficacy of the technique. Next, ligation of the ovarian pedicle via a standing colpotomy was conducted in five mares. Although the surgical procedure in these mares appeared to be quick and efficient, all five mares were noted to develop ovarian adhesions to surrounding abdominal viscera in either one or both ovaries postoperatively. Ovarian ischemia led to loss of ovarian activity based upon ultrasound examination, which was confirmed by a low plasma progesterone concentration in four of the five mares. During the postoperative period, four mares demonstrated clinical signs related to the ovarian adhesions and were euthanized. The postoperative complications associated with ovarian adhesions to abdominal viscera presented significant challenges, limiting the success of this study. While this technique resulted in ovarian ischemia and atrophy in four out of the five mares, we were unable to assess long-term effects on the health and reproduction of the mares due to the ovarian adhesions to the surrounding tissues and the potential for secondary complications. Although technically feasible, tubo-ovarian ligation via colpotomy does not appear to be a viable option for sterilization of mares using the described technique due to ovarian adhesions post procedure.

STERILIZATION OF HYBRID MARMOSET ( CALLITHRIX SP.) FEMALES: AN EVALUATION OF TWO SURGICAL METHODS.

Population control techniques, either permanent or reversible, are important tools for the management of wildlife in captive and natural environments. Among these, surgical sterilization provides a permanent solution to unwanted reproduction. Surgical techniques can differ in their invasiveness and in the subsequent effect on behavior and physiology. For social animals, techniques that preserve gonads, such as vasectomy for males and ligation of uterine tubes for females, may be preferred because they maintain important physiology that influences behavior. This study compared two sterilization procedures for captive hybrid marmosets ( Callithrix sp.). Twenty adult females undergoing tubal ligation were divided into two groups and received treatment either with a laparotomy or a laparoscopic method. The following parameters were evaluated for each female: duration of procedure, pain levels, weight gain, wound healing, adhesion, and inflammation. The results indicate that both techniques were equally effective. However, the conventional surgery may be more advantageous, because it is significantly shorter in duration, is only slightly more invasive, and requires less formal training of the surgeon.

Evaluation of endoscopic salpingectomy for sterilization of female Formosan macaques (Macaca cyclopis).

We evaluated the safety and postsurgical outcomes of endoscopic salpingectomy for sterilization of female Formosan macaques (Macaca cyclopis) as a method of population control. Nineteen adult female Formosan macaques were included in our study. The fallopian tubes of each anesthetized macaque were cauterized and excised endoscopically using a 2.7-mm rigid endoscope system. We recorded the complications encountered, and objectively scored the amount of hemorrhage throughout the procedure. Postoperative ovarian function was evaluated by monitoring the serum levels of sex hormones in ten of the macaques for two ovarian cycles following the salpingectomy. Two to 13 months later, eight of the 19 macaques underwent laparoscopy for the objective evaluation of inflammation at the surgical sites on the fallopian tubes. No major anesthetic- or surgical-associated complications were observed in any of the macaques. The hormonal evaluation showed cyclic ovarian function after salpingectomy in all of the ten macaques examined, and the parameters were comparable to those of other macaque species. The long-term postoperative level of inflammation at the surgical site was minimal to low, and was lower than that reported for other tubal occlusion techniques used in macaques. The use of a 2.7-mm rigid endoscope for salpingectomy in macaques is safe and efficient, with fewer postoperative complications than comparable sterilization techniques.

Live birth from slow-frozen rabbit oocytes after in vivo fertilisation.

In vivo fertilisation techniques such as intraoviductal oocyte transfer have been considered as alternatives to bypass the inadequacy of conventional in vitro fertilisation in rabbit. There is only one study in the literature, published in 1989, that reports live offspring from cryopreserved rabbit oocytes. The aim of the present study was to establish the in vivo fertilisation procedure to generate live offspring with frozen oocytes. First, the effect of two recipient models (i) ovariectomised or (ii) oviduct ligated immediately after transfer on the ability of fresh oocytes to fertilise were compared. Second, generation of live offspring from slow-frozen oocytes was carried out using the ligated oviduct recipient model. Throughout the experiment, recipients were artificially inseminated 9 hours prior to oocyte transfer. In the first experiment, two days after unilateral transfer of fresh oocytes, oviducts and uterine horns were flushed to assess embryo recovery rates. The embryo recovery rates were low compared to control in both ovariectomised and ligated oviduct groups. However, ligated oviduct recipient showed significantly (P<0.05) higher embryo recovery rates compared to ovariectomised and control-transferred. In the second experiment, using bilateral oviduct ligation model, all females that received slow-frozen oocytes became pregnant and delivered a total of 4 live young naturally. Thus, in vivo fertilisation is an effective technique to generate live offspring using slow-frozen oocytes in rabbits.

Surgical technique for tubal ligation in white-tailed deer (Odocoileus virginianus).

Surgical tubal ligation was used to sterilize urban free-ranging white-tailed deer (Odocoileus virginianus) as a methodology of a larger study investigating the influences of intact, sterile females on population dynamics and behavior. Deer were either trapped in clover traps (n = 55) and induced with an i.m. injection of xylazine and tiletamine/zolazepam or induced by a similar protocol by dart (n = 12), then intubated and maintained on isoflurane in oxygen. Over 3 yr, individual female deer (n = 103) were captured in Highland Park, Illinois, with a subset of females sterilized using tubal ligation by ventral laparotomy (n = 63). Other sterilization procedures included tubal transection by ventral (n = 1) or right lateral (n = 2) laparoscopy and ovariohysterectomy by ventral laparotomy (n = 1). One mortality (1/ 67, 1.5%) of a doe with an advanced pregnancy was attributed to a lengthy right lateral laparoscopic surgery that was converted to a right lateral laparotomy. The initial surgical modality of laparoscopy was altered in favor of a ventral laparotomy for simplification of the project and improved surgical access in late-term gravid does. Laparotomy techniques included oviductal ligation and transection (n = 14), application of an oviductal mechanical clip (n = 9), ligation and partial salpingectomy (n = 40), and ovariohysterectomy (n = 1). As of 2 yr poststerilization, no surgical does were observed with fawns, indicating that these procedures provide sterilization with low mortality in urban white-tailed deer.

Anesthetic management of an orangutan (Pongo abelii/pygmaeus) undergoing laparoscopic tubal ligation.

An adult hybrid orangutan (Pongo abelii/pygmaeus) was presented to a veterinary teaching hospital for laparoscopic tubal ligation. The orangutan was immobilized with the use of injectable anesthetic agents, then orotracheally intubated. Anesthesia was maintained with the use of isoflurane in oxygen, and positive-pressure ventilation was used to ensure adequate gas exchange. Parameters monitored included arterial blood pressure, ECG, capnometry, and arterial blood gases. Anesthesia was uneventful, and recovery was smooth.

Fetoplacental growth in sheep administered progesterone during the first three days of pregnancy.

We have previously shown that administration of progesterone during early pregnancy in sheep enhances fetal weight and crown-rump length. The present study examined the effect of this treatment on individual fetal organ weights and on placental growth and structure. Embryos that had been exposed to either a normal or a high concentration of progesterone on days 1-3 in initial recipient ewes were transferred at random to final recipient ewes that had or had not been treated with progesterone on days 1-3. Embryos in an additional group of ewes were exposed to progesterone on days 1-3 with oviducts of the ewes ligated. An increase in fetal weight was observed in the final recipient group that had been treated with progesterone (P< 0.01) but not in the initial group treated with progesterone. Fetal weight was increased (P< 0.05) in the initial recipients treated with progesterone plus ligation. Placental weight did not differ between any of the treatments in either initial or final recipients, while placental volumes of chorionic membrane and maternal crypts were increased by progesterone, with and without ligation, in initial recipients (P< 0.05). The responses of fetal weight in final recipients were associated with increases in the weight and linear dimensions of specific fetal components (e.g. brain, kidney, heart, spleen, total gut, head width, thorax circumference). Proportionate increases were observed for most parameters with the exception of brain, heart and M tibialis anterior weight; adjusted least squares means indicated disproportionate increases in these of 5 per cent, 32 per cent and 26 per cent respectively. Enhanced fetal weight in the progesterone plus ligation group was associated with increased (P< 0.05) heart weight; a disproportionate increase of 39 per cent was recorded. Increased fetal weight and fetal heart, skeletal muscle and brain weight were correlated with increased volumes and surface area of the fetal trophectoderm and maternal fetomaternal syncytium in the final recipients treated with progesterone. It is concluded that alteration of the embryo's environment during the first few days of development enhances fetal growth disproportionately, in close association with increased abundance of the exchange epithelia in the placenta.

Fertility of mares after unilateral laparoscopic tubal ligation.

OBJECTIVE: To develop a technique for laparoscopic tubal (oviductal) ligation and to evaluate pregnancy rates for mares that ovulated ipsilateral or contralateral to the ligated oviduct. STUDY DESIGN: Randomized prospective clinical trial comparing pregnancy rates after unilateral laparoscopic tubal ligation. ANIMALS: Twelve mares of light horse breeds. METHODS: One oviduct in each of 6 mares was surgically ligated with a laparoscopic technique; 6 other mares served as nonligated controls. Mares with unilateral tubal ligations (UTL) were inseminated with 500 million progressively motile sperm during 1 cycle when the dominant follicle was ipsilateral to the ligation site and 1 cycle when the dominant follicle was contralateral to the ligation site. Control mares were bred during 2 cycles regardless of the side of the dominant follicle. Pregnancy examinations were performed on days 12, 14, and 16 after ovulation by transrectal ultrasonography. RESULTS: None of the mares became pregnant when ovulations occurred from the ovary adjacent to the ligated oviduct. All 6 mares became pregnant on the first cycle when an ovulation occurred from the opposite ovary. Control mares became pregnant on 10 of 12 cycles (83.3 %). CONCLUSIONS: UTL was completely effective in preventing pregnancy when ovulation occurred ipsilateral to the ligation site. The surgical procedure did not interfere with the establishment of pregnancy when ovulation occurred from the contralateral ovary. CLINICAL RELEVANCE: UTL may be a clinically useful procedure for preparing a recipient mare for gamete intrafallopian transfer. The recipient mare could be allowed to ovulate and UTL would prevent fertilization of her oocyte but would not interfere with normal corpus luteum formation. The donor oocyte could be placed into the oviduct contralateral to the UTL site.

Surgical sterilization of free-ranging wolves.

The objective of the study was to determine whether surgical sterilization of both males and females in wolf pairs alters basic wolf social and territorial behaviors. Wolves were located from the air by snow-tracking methods and were tranquilizer-darted from a helicopter. Surgeries were performed either in a tent at the capture site or in a heated building in a nearby village. Six vasectomies and seven uterine horn ligations were performed in January and February of 1996 and 1997. Two females died: one likely related to the capture procedure, the other of a peritonitis unrelated to the surgery. One wolf had a litter. None of the wolves have shown changes in behavioral patterns. Surgical sterilization can be effective, but other, less invasive, fertility control techniques should be investigated.

Tubal ligation in the chimpanzee (Pan troglodytes) as a means of contraception.

Contraception of two chimpanzees was considered necessary for clinical reasons. After failure of reversible methods of contraception (an intrauterine device and a long-acting progestagen), tubal ligation was successfully performed, using a technique similar to one used in women.