Videoendoscopic evaluation of the mare's uterus: I. Findings in normal fertile mares.

The new generation of videoendoscopes uses an electronic, instead of an optical, system for image transmission. Advantages over conventional fibre-optic endoscopes include increased image quality, handling robustness and direct display of the image on a TV monitor for multiple simultaneous viewing. In the present study, hysteroscopy was performed on 14 normal fertile Welsh Pony and Thoroughbred mares at various times during the annual and ovarian breeding cycles. Oestrus was characterised by an oedematous, relaxed cervix lying on the floor of the vagina, diffuse oedema of the endometrium and the occasional accumulation of small amounts of clear secretions in the uterine lumen. In dioestrus, the cervix appeared tight and pale and was located in the centre of the vaginal fornix. The endometrium appeared thinner due to the reduction in interstitial fluid, which allowed the underlying blood vessels to become visible, but it still had a glistening surface as a result of endometrial gland secretions. The appearance of the uterotubal papillae reflected the changes in the cervix, being relaxed, pinkish and oedematous during oestrus but remaining pale, tight and erect in dioestrus (between Days 7 and 12 after ovulation). A flexible polythene cannula was passed into the uterine lumen through the working channel of the endoscope for directed collection of uterine fluid for cytological and bacteriological examinations. Site-directed biopsies of the endometrium were taken, with flexible forceps inserted through the working channel of the endoscope, or with rigid forceps passed through the cervix alongside the endoscope. Both methods enabled accurate visual selection of the sampling area but the rigid forceps were preferred due to the larger size of the piece of endometrium recovered.     

Videoendoscopic evaluation of the mare's uterus: III. Findings in the pregnant mare.

During a 5-year period 65 Pony and 20 Thoroughbred pregnant mares were subjected to videoendoscopic hysteroscopy from 10 to 266 days of gestation. The aims of these examinations were to 1) observe foetal and placental development in vivo (60 Pony and 10 Thoroughbred mares); 2) eliminate one of unicornuate twin conceptuses (9 Thoroughbred mares); 3) recover embryonic foetal and placental tissues non-surgically for experimental purposes (47 Pony mares); 4) induce focal separation of the placenta in late gestation as an experimental model of placentitis (5 pony mares and 1 Thoroughbred mare). It was possible to view the embryo and all constituent extra-embryonic membranes of the conceptus between Days 10 and 87 of gestation without having to perforate the allantochorion. This allowed study of physiological processes such as the coordinated uterine contractions responsible for conceptus motility between Days 7 and 17, active foetal movements, which began as early as Day 34, and invasion of chorionic girdle cells into the endometrium, which occurred between Days 34 and 38. From Day 90, vision of the foetus was reduced or prevented by the increased thickness of the allantochorion. Transendoscopic recovery of the conceptus was successful in all of 10 mares under 30 days of gestation, whereas only 10 of 18 attempts between Days 30 and 45 produced the conceptus without resorting to uterine lavage after initial rupture of the allantochorion. All 9 attempts to eliminate one of unilateral twin conceptuses were unsuccessful and the technique was abandoned as clinically unsuitable. Nevertheless, 9 of 22 (41%) single conceptuses remained viable after one or more hysteroscopic examinations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Embryo transfer in subfertile mares

Four subfertile mares (at least 2 barren years) were used as donors in an embryo transfer program. The embryo recovery rate was 50%, varying between 0-100. The transfer of 9 embryos resulted in the pregnancy rate of 44%. The efficiency of embryo transfer using subfertile mares is low. In this material 20% of flushings resulted in a pregnancy.     

Mycotic invasion of the mare's uterus

Uterine infections in three mares following repeated uterine manipulations and antibiotic therapy were caused by Aspergillus fumigatus in two cases and Candida albicans in the third. Two of the infections were noticed during dioestrus and one at oestrus and one mare produced a purulent vulval discharge. Large numbers of neutrophils, increased protein concentrations and the presence of fungal hyphae in flushings from the uterine lumen were indicative of active infection. The mycotic infections caused only transient aberrations of the oestrous cycle and recovery without treatment was completed within 23 days.     

Results of bacteriological and cytological examinations of the endometrium of subfertile mares in stud farms in Serbia

Uterine microbiology, antimicrobial susceptibility and endometrial cytology were investigated in a total of 51 mares with fertility problems from 16 different stud farms in Serbia. Uterine cultures were performed after collection with a double guarded uterine swab, and endometrial cytology was evaluated after collection of endometrial cells with a special device (cytology brush). In 21 of 51 mares, at least one bacterial species was isolated from the uterus; the most frequent were Streptococcus equi subsp. zooepidemicus (13 isolates) and E. coli (four isolates). All isolates of Streptococcus equi subsp. zooepidemicus were susceptible to penicillin. Results from endometrial cytology were inconsistent; in 17 animals with positive bacteriological culture, cytology was not altered. It can be concluded that in Serbia, as in many other contries, Streptococcus equi subsp. zooepidemicus is the main cause for equine endometritis. It can be easily diagnosed by uterine culture but endometrial cytology does not always prove the existence of an endometrial infection with this agent.     

Twin embryos in mares. II: Post fixation embryo reduction

Recent findings on the development and natural outcome of twins from Day 17 (immediately after fixation) to Day 40 are reviewed. Incidence of embryo reduction was increased significantly when the vesicles became fixed unilaterally, rather than bilaterally, and when the vesicles were unequal in diameter. Of 68 mares with twins on the day of fixation, post fixation embryo reduction occurred in 41 (60 per cent). The incidence of reduction was 41 of 48 (85 per cent) following unilateral fixation; reduction occurred in all of 22 mares with vesicles of dissimilar size (4 mm or more difference in diameter) and in 19 (73 per cent) of 26 mares with vesicles of similar size (0 to 3 mm difference). Embryo reductions were complete (vesicle no longer visible ultrasonically) by Day 20 (59 per cent of the reductions), during Days 21 and 30 (27 per cent), or Days 31 to 38 (14 per cent). In 80 per cent of the early reductions (by Day 20) the eliminated vesicle disappeared within one day. Reductions that occurred after Day 20 were preceded by a gradual decrease in size. As the number of days after Day 17 increased, the frequency of reduction decreased and the time required for completion of reduction increased. When the twins were dissimilar in diameter (4 mm or more), they were more likely to undergo reduction by Day 20. In summary, dissimilarity in diameter increased the likelihood of unilateral fixation, increased the incidence of reduction for unilaterally fixed vesicles, hastened the day of occurrence of reduction and shortened the interval from initiation to completion of reduction. The deprivation hypothesis proposes that embryo reduction occurs when a major portion of the three walled area of the yolk sac or the vascularised wall of the yolk sac or allantoic sac is in apposition with the wall of the adjacent vesicle rather than with the endometrium; the vesicle is deprived of adequate embryonal-maternal exchange and therefore regresses.     

The effect of detomidine hydrochloride on the electrical activity of uterus in pregnant mares

The effect of detomidine on the electrical activity of the uterus was studied during the last trimester of pregnancy in 6 mares. The effect was observed in 3-5 min after the i.m. injection and it lasted for 50-70 min. 20 and 40 micrograms/kg b.w. doses of detomidine decreased the myometrial electrical activity, whereas 60 micrograms/kg dose did not have any effect on the activity. The results suggested that 20, 40 and 60 micrograms/kg b.w. doses of detomidine can be administered to mares during the last trimester of pregnancy without the risk of abortion induced by increased uterine electrical activity.     

Absorption of two trimethoprim/sulphonamide combinations from the uterus of pony mares

Plasma drug concentrations were measured after two commercially available potentiated sulphonamides, trimethoprim and sulfadoxine and trimethoprim and sulphadiazine, were infused daily for 2 and 3 days, respectively, into the uteri of pony mares which had been mated before ovulation. Intravenous administration of trimethoprim and sulfadoxine allowed uterine absorption of trimethoprim (23-43%) and sulfadoxine (29-34%) to be calculated. After intra-uterine administration trimethoprim and sulphadiazine were detected in the milk of a lactating mare. In order to maintain plasma concentrations likely to be required for clinical efficacy of both drugs they should be administered every 12 h. However, infusions of both preparations caused endometrial inflammation as assessed by cytological and histological examination and this may have been responsible for the low pregnancy rate.     

Elevating the uterus (uteropexy) of five mares by laparoscopically imbricating the mesometrium

Reasons for performing study: There is a need for study of a method for restoring a ventrally positioned uterus to a horizontal position involving fertility of mares with delayed uterine clearance. Hypothesis: A ventrally‐angled uterus can be elevated to a horizontal position using a laparoscopic technique. Objective: To develop a laparoscopic technique of imbricating the mesometria to elevate the uterus to a horizontal position. Methods: The right and left mesometria of 5 pluriparous mares, all barren for 1–8 years (mean 3.8 years), with a pendulous, ventrally‐angled uterus were shortened laparoscopically, by imbrication, with the mares standing, to raise the uterine body and horns to a horizontal position. Sutures were placed through the dorsal aspect of the uterine body and uterine horn and the adjacent region of the mesometrium using a simple continuous suture pattern. Results: The uterus of all 5 mares was elevated successfully to a horizontal position. Three of the mares became pregnant the same year, without other treatment, after the procedure. Conclusions: A pendulous, ventrally‐angled uterus can be returned to a normal, horizontal position by imbricating the mesometria, using a laparoscopic technique. Potential relevance: Elevating a ventrally‐angled uterus to a horizontal position may improve egress of uterine debris, thereby improving fertility.     

Clinical management of the subfertile stud dog.

Many subfertile stud dogs can sire pups with appropriate management. Determination of the area of the problem (libido, ability to breed, semen quality) is the first step. Each of these areas can often be improved or managed. A complete history, physical examination, and semen evaluation should be performed on every patient. In specific cases, additional diagnostics may be helpful, including a CBC, biochemistry profile, urinalysis, semen cultures, ultrasonography, and biopsy. Management of breeding, including ovulation timing and intrauterine insemination, can be vital in dogs with low spermatozoal numbers or motility. Treatment of underlying prostatic disease can dramatically improve semen quality and fertility.     

Effect of administration of phenylbutazone or progesterone on recovery of embryos from the uterus of mares 5 days after ovulation.

Twelve horse mares were used to investigate the effect of phenylbutazone or progesterone administration on uterine tubal motility, as reflected by embryo recovery from the uterus on day 5 after ovulation. Four treatment groups were used: group A (controls), in which uterine flush was performed 7 to 11 days after ovulation; group B (5-day controls), in which uterine flush was performed 5 days after ovulation; group C, in which uterine flush was performed 5 days after ovulation following administration of phenylbutazone (2 g, IV) on day 3; and group D, in which uterine flush was performed 5 days after ovulation following administration of progesterone in oil (250 mg, IM) on days 0, 1, and 2. Each mare was randomly assigned to each group once. Embryo recovery for each group was: group A, 13 embryos from 12 mares; group B, 3 embryos from 12 mares; group C, 4 embryos from 11 mares; and group D, 1 embryo from 11 mares. Recovery of embryos on day 5 in 3 of 12 nontreated mares indicated that equine embryos may enter the uterus before day 6. Neither treatment increased embryo recovery from the uterus on day 5 over that from the uterus of the 5-day controls.