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Summary Objective: Transvaginal ultrasound-guided aspiration (TUA) is a procedure which can be used for the reduction of twins post-fixation in the mare. The aim of this study was to evaluate the effect of the age of mares and the day of gestation on the outcome of TUA treatment. Material and methods: In 88 mares, diagnosed pregnant with twins, TUA of the yolk sac or allantoic fluid was performed between day 30 and 62 of gestation. Mares were aged 3–22 years. Ultrasonographic examination for a viable singleton pregnancy was performed by referring veterinarians 5–7 days and 4 weeks after TUA. Based on reported findings, effects of age and day of gestation on pregnancy rates were evaluated. Results: Four weeks after TUA, 67% of the cases resulted in a viable singleton pregnancy. Five to 7 days after TUA treatment, the success rate was 74%. The gestational period did not affect the outcome, irrespective of the age of the mare. In contrast, success rates decreased with increasing age of the mares (84% ≤ 7 years vs. 67% 8–14 years vs. 57% ≥ 15 years). In mares aged 8–14 years, a decrease in singleton pregnancies was observed, if TUA was performed after day 35 of gestation. Success rates were slightly higher, if twin vesicles were localized within separate uterine horns (73%) as compared to the same horn (66%). Differences in singleton pregnancy rates were not statistically significant (p > 0.05). Conclusions and clinical relevance: TUA was found to be an effective procedure for reduction of twin pregnancies performed at days 30–62 of gestation. Success rates for singleton pregnancies were high for young mares ≤ 7 years old (84%) and middle aged mares treated before day 36 of pregnancy (74%). Duration of pregnancy at the time of TUA did not have a major impact on the outcome. Nevertheless, the procedure should optimally be performed around days 32–35 of pregnancy to allow for the possibility of natural reduction before treatment and rebreeding in case of a total pregnancy loss after TUA.

Summary: Late pregnancy check ups in mares during advanced gestation by transabdominal ultrasound bring reliable results on fetomaternal and fetal well-being. Fetal gonads can be scanned as well. Aim of this study was to evaluate accuracy of fetal gender determination by using B-Mode and Doppler ultrasonography video images analyzed by different raters. The accuracy of these diagnoses was compared among the raters. Pregnancy checks were performed on different stud farms in the mid-west of Germany. The day of gestation was derived from breeding records, and the mares were examined between 70 -240 days pregnant. Fetal sex was determined as well by B-Mode and Doppler sonography. Examinations were videotaped. Gonads with homogenous structure and a hyperechogenic line along the longitudinal axis, or an intense Doppler signal along this axis were assigned to be male. Gonads with bizoned echogenicity and a strong circular Doppler signal were assigned female. To review the practicability and repeatability of gender determination 100 videotapes were selected and shown to 20 voluntary raters who correlated videotapes and fetal gender. Confirmation of gestation and fetal well-being during advanced gestation (90 -240 days) by transabdominal ultrasound examination is practicable. Gender determination can be accomplished by a combination of B-Mode and Doppler sonography. The best results can be accomplished during 4th (75 %) and 5th (62 %) month of gestation, especially by using Doppler ultrasonography. Practitioners who are unexperienced in gender determination can complete the task based on videotapes showing fetal gonads. Characteristic optical features can be identified better referring to vascularisation detected by colour Doppler ultrasonography. In conclusion gender determination by transabdominal sonography can be conducted by using a combination of B-Mode and Doppler sonography. Optimal working conditions and videotaping the examination can increase the accuracy. Using colour Doppler helps to find distinctive features and determine the gender with greater accuracy. The accuracy of the diagnoses is optimal between 4-5 month of gestation.Keywords: mare / gender determination / transrectal ultrasonography / transabdominal sonography / reproduction Citation: Tönissen A., Martinsson G., Pricking S., Otzen H., Ertmer F., Rau J., Sielhorst J., Rohn K., Sieme H. (2016) Transabdominal ultrasonographic determination of fetal gender in the horse during mid-gestation -a comparative study using randomized video images to investigate variation in diagnostic performance among raters, and the effect of month of gestation. Pferdeheilkunde 32,[29][30][31][32][33][34][35]

Summary: This study aims to review current knowledge on equine fetal sexing with special reference to the authors field experience using the non-invasive transabdominal approach. Early gender determination performed transrectally by identifying the genital tubercle is specific with a small time frame; it is best performed from day 59 until 68. The examiner has to be experienced to scan the right planes for finding the genital tubercle in either sex. Advanced sex determination can be performed transrectally from 90 up to 140 days of gestation, afterwards reaching the fetus hindquarters transrectally is almost impossible and the transabdominal alternative has to be chosen. External genitalia and gonads have to be found and good knowledge of fetal anatomy is required. For more advanced gestation, the importance of representing the gonads and especially outlining their B-Mode echotexture and vascularisation by Doppler sonography increases. For the transrectal approach for gender determination, mares have to be calm and relaxed, so the use of sedation and smooth muscle relaxants might be necessary and the risk of perforating the rectum has to be taken into consideration. Transabdominal examination shows high acceptance in mares and bears a low risk, sedation is not necessary and movement of mare and fetus can be compensated easily by moving the ultrasound probe along the abdomen. Equine fetal sex determination is a tool in equine reproductive medicine which becomes more important and interesting for breeders in order to plan the mare s future breeding prospects. With enough time, patience, practice and good equipment it can be performed by practitioners easily as an additional service for clients. The method to be selected depends on the stage of gestation and on fetal presentation. If movements of the fetus prevent the accomplishment of sex determination, the examination should be repeated later. Advantages of gender determination during advanced gestation by transabdominal ultrasound other than economical reasons are the accomplishment of a check up on pregnancy and fetal well-being, great acceptance by the clients and a good way to perform gestation control in ponies and small horses, although this may take more time for preparation and examination.Keywords: mare / fetal gender determination / transrectal ultrasonography / transabdominal sonography / reproduction Citation: Tönissen A., Martinsson G., Otzen H., Schürmann K., Schütze S., Ertmer F., Kassens A., Sielhorst J., Brehm R., Sieme H. (2015) To perform fetal gender determination in the mare by ultrasound during early and advanced gestation. Pferdeheilkunde 31,[153][154][155][156][157][158]

Summary: Early diagnosis of endometritis and identification of pathogens involved are essential to choose the correct treatment and optimize fertility in the mare. The objective of this study was to compare results from endometrial swabs taken through the vagina manually, by speculum and forceps, and by iVetscope ® , a recently introduced rigid endoscope equipped with a monitor and two working channels, to identify the most reliable swabbing technique. Endometrial swabs for microbioloy and cytobrush samples to assess endometrial cytology were obtained from 88 estrous mares in a commercial breeding program by three different sampling techniques. Following a gynecological examination endometrial samples were taken transvaginally using a double-guarded uterine culture swab and cytobrush manual (MAN) (n =29), a speculum (SPEC) (n = 30) or iVetscope ® (SCOP) (n = 29). Endometrial swabbing was repeated after 48 h. The culture results assessed in an internationally accredited laboratory were related to the endometrial cytology (> 5 PMNs/10 HPF). The three different sampling methods showed significant differences in bacterial growth, especially in the second sampling after 48 hours. While 28/29, 97 % of MAN-samples showed bacterial growth, bacteria were isolated from 22/29, 76 % of SPEC-and 20/30, 67 % of SCOP-samples (p < 0.05). Facultative pathogenic bacteria were significantly more often isolated from samples taken manually (16/29, 55.2 %) than samples taken by speculum (5/29, 17.2 %) or iVetscope ® (4/30, 13.3 %) 48 hours after the first sampling (p < 0.05). An increased number of samples with bacterial growth of more than three bacterial species in the first and second swab (31% and 37.9 % in the MAN-group versus 3.3 % and 0 % in the SCOP-group and 0 % and 6.9 % in the SPEC-group at the first and second sampling, respectively; p < 0.01) reveals bacterial contamination from the caudal reproductive tract in swabs taken via the transvaginal manual approach. These results strongly recommend endometrial swabbing by instrumental techniques (speculum and forceps, or iVetscope ® ). Although, these swabbing techniques might be slightly more time consuming and require more material, the significantly reduced bacterial contamination underlines the relevance of the swabbing technique in equine practice.