Effects of timing of induced luteolysis in embryo donor mares on reproductive performance and pregnancy rate in recipient mares

The objective was to evaluate the effects of giving prostaglandin F(2 alpha) (PGF) to donor mares 48 h prior to embryo collection. Non-lactating donor mares (n = 20 estrous cycles in 10 mares), ranging from 2.5 to 10 y of age and 400 to 500 kg of body weight were used from September 2004 to February 2005 in the southern hemisphere (Brazil). Donor mares were randomly assigned in a cross-over design study. During a Treated cycle, 7.5 mg PGF was given 48 h prior to embryo collection, whereas in the Control cycle, 7.5 mg PGF was given at embryo collection. In Treated Cycles, serum progesterone concentrations decreased between the day of PGF treatment and the day of embryo collection (13.9 +/- 5.4 and 0.5 +/- 0.3 ng/mL, respectively; P < 0.05). In Treated versus Control cycles, the interovulatory interval was shorter (14.9 +/- 0.9 vs 17.5 +/- 1.1 d, P < 0.05). However, there was no significant difference between these groups for the interval from PGF to ovulation (average, 9.8 d), embryo recovery rate (average, 75%), embryo quality, uterine protein concentration, and pregnancy rate in recipient mares (average, 87% at 15 d after ovulation, with no pregnancy loss detected by 60 d). In conclusion, giving donor mares PGF 48 h prior to embryo collection reduced the average interovulatory interval by approximately 2.5 d, thereby potentially increasing the numbers of embryos that could be collected during a breeding season, with no deleterious effects on embryo recovery rate, embryo quality, or pregnancy rate in recipient mares. (c) 2011 Elsevier B.V. All rights reserved.

Yolk sac remnant in a mini-pony foal

Few reports are available concerning yolk sac remnants in the equine species, with little information on histopathological findings. A stillborn mini-pony foal showed a fluid-filled mass, measuring about 10 cm in circumference, close to the umbilical cord. Microscopic examination better defined the structures seen in the cyst.

Follicular dynamics in Mangalarga mares.

Ovarian follicular activity was studied by ultrasonography during 17 oestrous cycles in 9 Mangalarga mares during the second half of the ovulatory season. Sixteen oestrous cycles were considered normal and one 3-wave cycle showing a prolonged luteal phase was considered atypical. Daily ultrasonographic examinations were performed and the compiled data on follicular dynamics were studied retrospectively. One major wave of follicular growth was observed in 13 of the 16 normal cycles (81.25%), whereas 2 major waves occurred in 3 cycles (18.75%). The mean (+/- s.d.) days of emergence of the primary wave of follicular development in cycles containing one or 2 waves were Day 6.0 +/- 2.3 and Day 11.0 +/- 1.0, respectively. The secondary wave of follicular development in 2-wave cycles emerged on Day 0.0 +/- 3.6. The day of wave divergence for primary waves of follicular development in cycles which exhibited one or 2 major waves were Day 12.2 +/- 3.5 and Day 17.3 +/- 3.0, respectively. Divergence of secondary waves occurred in only one of the 3 cycles which exhibited 2 major follicular waves (Day 7). The mean (+/- s.d.) maximum diameters of the dominant follicle in the primary wave of oestrous cycles exhibiting one and 2 major waves were 39.0 +/- 3.9 mm and 34.7 +/- 2.5 mm, respectively. The mean (+/- s.d.) maximum diameter of the dominant follicle present in the secondary wave was 34.3 +/- 11.0 mm. The mean (+/- s.d.) lengths of the interovulatory intervals for cycles containing one and 2 major waves were 19.4 +/- 2.2 and 23.3 +/- 2.5 days, respectively. These data indicate that most Mangalarga mares show one major follicular wave during the oestrous cycle but a small percentage of mares show 2 major waves.

Superovulation in Cycling Mares Using Equine Follicle Stimulating Hormone (eFSH)

Superovulation would potentially increase the efficiency and decrease the cost of embryo transfer by increasing embryo collection rates. Other potential clinical applications include improving pregnancy rates from frozen semen, treatment of subfertility in stallions and mares, and induction of ovulation in transitional mares. The objective of this study was to evaluate the efficacy of purified equine follicle stimulating hormone (eFSH; Bioniche Animal Health USA, Inc., Athens, GA) in inducing superovulation in cycling mares. In the first experiment, 49 normal, cycling mares were used in a study at Colorado State University. Mares were assigned to 1 of 3 groups: group 1, controls (n = 29) and groups 2 and 3, eFSH-treated (n = 10/group). Treated mares were administered 25 mg of eFSH twice daily beginning 5 or 6 days after ovulation (group 2). Mares received 250 (of cloprostenol on the second day of eFSH treatment. Administration of eFSH continued until the majority of follicles reached a diameter of 35 mm, at which time a deslorelin implant was administered. Group 3 mares (n = 10) received 12 mg of eFSH twice daily starting on day 5 or 6. The treatment regimen was identical to that of group 2. Mares in all 3 groups were bred with semen from 1 of 4 stallions. Pregnancy status was determined at 14 to 16 days after ovulation. In experiment 2, 16 light-horse mares were used during the physiologic breeding season in Brazil. On the first cycle, mares served as controls, and on the second cycle, mares were administered 12 mg of eFSH twice daily until a majority of follicles were 35 mm in diameter, at which time human chorionic gonadotropin (hCG) was administered. Mares were inseminated on both cycles, and embryo collection attempts were performed 7 or 8 days after ovulation. Mares treated with 25 mg of eFSH developed a greater number of follicles (35 mm) and ovulated a greater number of follicles than control mares. However, the number of pregnancies obtained per mare was not different between control mares and those receiving 25 mg of eFSH twice daily. Mares treated with 12 mg of eFSH and administered either hCG or deslorelin also developed more follicles than untreated controls. Mares receiving eFSH followed by hCG ovulated a greater number of follicles than control mares, whereas the number of ovulations from mares receiving eFSH followed by deslorelin was similar to that of control mares. Pregnancy rate for mares induced to ovulate with hCG was higher than that of control mares, whereas the pregnancy rate for eFSH-treated mares induced to ovulate with deslorelin did not differ from that of the controls. Overall, 80% of mares administered eFSH had multiple ovulations compared with 10.3% of the control mares. In experiment 2, the number of large follicles was greater in the eFSH-treated cycle than the previous untreated cycle. In addition, the number of ovulations during the cycle in which mares were treated with eFSH was greater (3.6) than for the control cycle (1.0). The average number of embryos recovered per mare for the eFSH cycle (1.9 ± 0.3) was greater than the embryo recovery rate for the control cycle (0.5 ± 0.3). In summary, the highest ovulation and the highest pregnancy and embryo recovery rates were obtained after administration of 12 mg of eFSH twice daily followed by 2500 IU of hCG. Superovulation with eFSH increased pregnancy rate and embryo recovery rate and, thus, the efficiency of the embryo transfer program.

Description and genetic analysis of three sets of monozygotic twins resulting from transfers of single embryos to recipient mares

Case Description-3 sets of monozygotic twins resulting from transfers of single embryos to recipient mares were examined. Clinical Findings-In all 3 recipient mares with twin pregnancies, only 1 embryonic vesicle was detected before day 25 of gestation. In 1 recipient mare, 2 apparent adjacent vesicles, each containing an embryo with a heartbeat, were visualized on ultrasonographic examination on day 37 of gestation. The other 2 recipient mares underwent ultrasonographic examination on day 30 of gestation, at which time only 1 vesicle and embryo was identified. In these latter 2 recipient mares, however, a thorough ultrasonographic examination for a second conceptus on day 30 had not been performed, as only 1 embryo had been transferred and visualized on early ultrasonographic examination. Treatment and Outcome-All twin pregnancies resulted in death of both fetuses. Genetic analysis confirmed that each set of monozygotic twins originated from the transferred embryo. Clinical Relevance-Monozygotic twin pregnancy may occur after embryo transfer; thus recipient mares should be examined thoroughly for multiple conceptuses, especially between 25 and 30 days of gestation. At this time, the allantoides of monozygotic twins should be visible ultrasonographically and effective management may still be possible.

Doppler ultrasonography principles and methods of evaluation of the reproductive tract in mares

Background: Doppler ultrasonography is a non-invasive real time pulse-wave technique recently used for the transrectal study of the reproductive system hemodynamics in large animals. This technic is based in the Doppler Effect Principle that proposes the change in frequency of a wave for an observer (red blood cells) moving relative to the source of the respective wave (ultrasonic transducer). This method had showed to be effective and useful for the evaluation of the in vivo equine reproductive tract increasing the diagnostic, monitoring, and predictive capabilities of theriogenology in mares. However, an accurate and truthful ultrasonic exam requires the previous knowledge of the Doppler ultrasonography principles. Review: In recent years, the capabilities of ultrasound flow imaging have increased enormously. The current Doppler ultrasound machines offer three methods of evaluation that may be used simultaneously (triplex mode). In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the tissue that can be viewed as a two-dimensional gray-scale image on screen. This mode is primarily used to identify anatomically a structure for its posterior evaluation using colored ultrasound modes (Color or Spectral modes). Colored ultrasound images of flow, whether Color or Spectral modes, are essentially obtained from measurements of moving red cells. In Color mode, velocity information is presented as a color coded overlay on top of a B-mode image, while Pulsed Wave Doppler provides a measure of the changing velocity throughout the cardiac cycle and the distribution of velocities in the sample volume represented by a spectral graphic. Color images conception varies according to the Doppler Frequency that is the difference between the frequency of received echoes by moving blood red cells and wave frequency transmitted by the transducer. To produce an adequate spectral graphic it is important determine the position and size of the simple gate. Furthermore, blood flow velocity measurement is influence by the intersection angle between ultrasonic pulses and the direction of moving blood-red cells (Doppler angle). Objectively colored ultrasound exam may be done on large arteries of the reproductive tract, as uterine and ovary arteries, or directly on the target tissue (follicle, for example). Mesovarium and mesometrium attachment arteries also can be used for spectral evaluation of the equine reproductive system. Subjectively analysis of the ovarian and uterine vascular perfusion must be done directly on the corpus luteum, follicular wall and uterus (endometrium and myometrium associated), respectively. Power-flow imaging has greater sensitivity to weak blood flow and independent of the Doppler angle, improving the evaluation of vessels with small diameters and slow blood flow. Conclusion: Doppler ultrasonography principles, methods of evaluation and reproductive system anatomy have been described. This knowledge is essential for the competent equipment acquisition and precise collection and analysis of colored ultrasound images. Otherwise, the reporting of inconsistent and not reproducible findings may result in the discredit of Doppler technology ahead of the scientific veterinary community.

Ovarian response to porcine FSH in association with ablation-induced or spontaneous follicular wave development during the estrous cycle in crossbred and Brazilian Warmblood mares

The primary objective of this study was to examine the follicular and ovulatory responses following treatment with pFSH in association with ablation-induced or spontaneous follicular wave emergence or follicle deviation during diestrus in crossbred (Mangalarga × Arabian) and Brazilian Warmblood mares with a propensity for spontaneous multiple ovulations; secondary considerations were given to the collection of embryos In Experiment 1, crossbred mares were administered (im) saline (control, n= 7) or pFSH (25 mg) when the largest follicle of the ablation-induced follicular wave reached ≥13 mm (n= 7) or ≥20 mm (n= 7) or, after pre-treatment ovulation (Day 0) on Day 6 (n= 7) In Experiment 2, crossbred mares were administered (im) saline (control, n= 10) or a larger dose of pFSH (50 mg, n= 7) when the largest follicle of the ablation-induced follicular wave reached ≥13 mm In Experiment 3, Brazilian Warmblood mares were administered (im) saline (control, n= 7), pFSH (25 mg, n= 7 or 50 mg, n= 5) or EPE (12.5 mg, n= 7) as a positive control on Day 6 Ultrasonic technology was used to ablate all follicles ≥8 mm and to monitor follicular development and detect ovulation Treatment with pFSH or EPE was done twice daily until the largest follicle reached ≥32 mm; thereafter, hCG (2500 IU) was administered (iv) when the largest follicle reached ≥35 mm Artificial insemination was done 12 h after hCG and embryo collections were done 8 d after post-treatment ovulations In Experiments 1 and 2, treatment of crossbred mares with pFSH post-ablation in association with the expected time of wave emergence or follicle deviation did not (P> 0.05) enhance the follicular or ovulatory responses or collection of embryos compared to controls In Experiment 3, although the enhanced ovulatory response of mares to EPE at the expected time of spontaneous wave emergence was not different (P> 0.05) from controls, it was greater (P< 0.05) than the response to pFSH In conclusion, the novelty of using follicle ablation prior to pFSH treatment at the time of wave emergence or follicle deviation did not enhance the follicular or ovulatory responses or collection of embryos to treatment in crossbred mares In addition, the hypothesis that Brazilian Warmblood mares with a greater propensity for spontaneous multiple ovulations are as responsive to pFSH compared to EPE was not supported Thus, the combined experimental results of the present study continue to support the general consensus that pFSH is relatively ineffective for follicular superstimulation/superovulation in mares © 2012 Elsevier B.V.

Laparoscopic adhesiolysis in a mini pony

Background: Intraperitoneal adhesions are common in equines, especially following exploratory celiotomy. Adhesiolysis is the treatment of choice for patients presenting postsurgical adhesions. Laparoscopic approach for adhesiolysis presents several advantageous aspects in human patients. The aim of the current study was to report a case of successful laparoscopic adhesiolysis in a mini pony horse. Case: A male Shetland Pony, weighing 140 kg, was admitted under complaint of right hind limb trauma and treated surgically for metatarsal fracture reduction. The patient has also had intermittent episodes of colic and was always treated clinically without major complications. The pony had no history of previous abdominal surgery and no episodes of acute abdomen were seen during hospital stay. Three months following ostheosynthesis, an exploratory laparoscopic approach was carried out to assess the possible cause or consequences of the episodes of acute abdomen. The patient was submitted to general anesthesia, positioned in dorsal recumbency and the abdomen was clipped and aseptically prepared for surgery. During the laparoscopic inspection, there were adhesions involving the ventral abdominal wall and a ventral mesogastric segment of duodenum. Laparoscopic adhesiolysis was performed using a two-port approach, by gently breaking the adhesion bands using meticulous traction with a 10-mm laparoscopic atraumatic Babcock forceps. Afterwards, the intestinal loop was rinsed with heparin sodium solution diluted in normal saline. The pneumoperitoneum was completely drained and the trocars sequentially withdrawn from the abdominal wall. The synthesis of the muscular layer was carried out using an interrupted cross mattress pattern, followed by synthesis of the skin with an interrupted cushion pattern. Total surgical time was 58 min. the patient was able to recover without complications. In the early postoperative period, the surgical recovery was considered excellent. No apparent adhesion involving the previously affected intestinal loop was found during the ultrasound exam following 15 days of surgery. Furthermore, the surgical wounds had healed completely, with no complications. Discussion: In the current case report, the primary cause of the acute abdomen episodes was not determined since the patient had never undergone abdominal surgery. It was hypothesized that an acute inflammation of the duodenal loop that was involved by the adhesion bands may have triggered the adhesiogenesis. Laparoscopy was efficient and presented a short operative time, due to magnification of image and adequate observation of structures surrounded by adhesion bands. Although the use of Babcock forceps is not usually recommended for adhesiolysis in the current literature, it was both effective in manipulating the bowel and performing the adhesiolysis. The heparin solution diluted in normal saline was effective in preventing the recurrence of new adhesions, which was evidenced by ultrasonography following 15 days. The laparoscopic approach usually minimizes the new formation of adhesions as trauma to the peritoneal surfaces is minimized by the use of delicate instruments, as observed in the current study. In addition, laparoscopy reduces the possibility of contact among the peritoneal surfaces and foreign bodies, such as gauze, glove powder and room air particles. Moreover, it maintains the abdominal surfaces in adequate humidity environment.

Determining the gestational age of crioulo mares based on a fetal ocular measure

The practice of covering in herds is often used in Crioulo breeding farms, thus not allowing the determination of ovulation dates and the early detection of pregnancies. This fact complicates the estimation of gestational age after 70 days of conception. This study aimed to evaluate the diameter of the fetal orbits of Crioulo mares to develop a formula to estimate a gestational date. Measurements of 164 fetal ocular orbits were performed in 124 Crioulo mares with gestational ages ranging between 119 and 341 days. The current study observed a linear growth pattern of Crioulo fetal orbits up to 341 days of gestation. Thus, obtaining a suitable linear regression model to determine the gestational age of Crioulo mares based on fetal ocular orbit diameter measure is possible. The obtained model was y = 8.3756x + 11.90, where y represents the gestational age in days, and x represents the diameter of the fetal ocular orbit in millimeters. This formula had anr2 of 0.985 (P < .001). We conclude that this model allows researchers and veterinarians to accurately estimate the gestational age of Crioulo mares between 4 and 11months of pregnancy. © 2013 Elsevier Inc.