Uterine Infection and Inflammation:Endometritis and Cysts in Horses
Endometritis is a major cause of reduced fertility in mares.
Contamination of the uterus can occur is several ways:
Infectious agents may cause an uterine infection if the uterine clearance mechanism is defective or if the amount of infectious agents are to large to cope with for this mechanism. A common problem associated with genital infection is pneumovagina. When this condition exists the barrier function of the vulvar lips, the vestibulovaginal sphincter and cervix is impaired. Because of the negative intra-abdominal pressure air together with debris and bacteria is aspirated into the genital tract causing infection.
Endometritis can occur in mares of all breedings and ages, but is more seen in older multiparous mares because of the vulvar conformational changes. Another problem associated with endometritis in older mares, especially in old maiden mares, is the tight cervix.Breed and bodycondition also have some influence on the negative intra-abdominal pressure.
After gathering general information about the mare like age, amount of foals and previous parturations it is important to ask the owner about external signs of infection. For example matting of tail hairs or exsudate at the ventral commissure of the vulva.
In the case of mares susceptible to postmating endometritis it is very important to try to indentify them before breeding so they can be managed in a manner to enhance fertility.
The uterine lumen of the normal fertile mare is sterile despite the fact that the reproductive tract is contaminated with bacteria from the act of breeding, foaling, and veterinary procedures. Mares with defective vulval conformation can aspirate air and bacteria into the vagina, which can cause endometritis.The uterus responds to these bacteria with a rapid influx of neutrophils. Normally these neutrophils kill the bacteria rapidly (within 24 hours). The inflammatory by
- products then are mechanically removed and the endometritis resolves itself. Failure to resolve this inflammation results in the “susceptible” mare. Susceptible mares have a delay in uterine clearance and the inflammatory by
- products accumulate as uterine fluid. Such mares have a reduced pregnancy rate due to an unsuitable environment for the early developing conceptus.
- Induced Endometritis
At breeding, the mare’s uterine lumen becomes contaminated with microorganisms and debris. Even if mares are bred by artificial insemination, semen is deposited directly into the uterus. Spermatozoa and seminal plasma, even without bacterial contamination induce an uterine inflammatory response. The intensity of the reaction is dependent on the concentration and/or volume of the inseminate (e.g., frozen semen induced a stronger inflammatory reaction in the uterus then fresh or extended semen). The intensity of the inflammatory response following insemination depends on the sperm themselves rather than any extender and is not different for live or dead spermatozoa.In most mares, this transient endometritis resolves spontaneously within 24
- 72 hours so that the environment of the uterine lumen is compatible with embryonic and fetal life. It is important not to regard this endometritis as a pathological condition. Rather, it is a physiological reaction to clear excess sperm, seminal plasma, and inflammatory debris from the uterus before the embryo descends from the oviduct into the uterine lumen 5 1/2
- 6 days after fertilization. However, if the inflammatory reponse persists after Day 4 or 5 after ovulation the intra
- uterine environment is not suited for the conceptus. Another concequence of the inflammatory response is the premature release of PGF2
- alpha resulting in luteolysis, a rapid decline of progesterone and an early return to estrus. In general, reduced resistance to endometritis is associated with advancing age and multiple foalings. Susceptibility to endometritis is not an absolute state since failure of uterine defense mechanisms needs only to slow the process of eliminating the infection. In the practice situation, a wide range of susceptibility to endometritis is seen and it must not be thought that mares can be neatly packaged into “resistant” or “susceptible.”
The Old Maiden Mare Syndrome
It is particularly important to recognize and manage appropriately the older maiden mare, as in many cases these mares are susceptible to post
- breeding endometritis even though they have never been bred before. Often sport or Warmblood mares might not be presented to be bred until they are in their teens and these older maiden mares can be very difficult to get in foal.Endometrial biopsy samples reveal glandular degenerative changes and stromal fibrosis (endometrosis) as an inevitable consequence of aging despite the fact the mares have not been bred. Another common problem of these mares is uterine fluid. Often an older maiden mare has an abnormally tight cervix that fails to relax properly during estrus so that fluid is unable to drain, and thus it accumulates in the uterine lumen. In many cases, this fluid is negative for bacterial growth and presence of neutrophils.Once the mare is bred, the fluid accumulation will be aggravated due to poor lymphatic drainage and impaired myometrial contraction, compounded by the tight cervix. The amount of intrauterine fluid will vary in individual mares, ranging from a few milliliters to more than a liter in extreme cases. To maximize the fertility of these mares, it is vital that the veterinarian be aware of the possibility of this type of uterine and cervical pathology. All too often owners assume that the fertility of these mares is comparable to that of young maiden mares; one of the most important aspects of breeding the old maiden mare is to make the owner aware that there is a high possibility that she will be a problem. These mares must be considered highly susceptible and managed accordingly.
After a general clinical examination the external genitalia of the mare must be inspected for signs of infection like matted tail hairs and/or exsudate. Checking the vulvar conformation and closure is another important part of the examination.
With the help of a vaginal speculum the vagina and cervix can be inspected for signs of inflammation like reddening and increased vascularity of the vaginal wall. Also discharge through the cervix and the presence of pooled urine or debris in the anteriour vagina can be indentified.
Endometrial Culture And Cytology
Diagnosis of endometritis can be made by collection of concurrent endometrial swab and smear samples during early estrus for bacteriological culture and cytological examination. This allows time for resolution prior to breeding, and maximizes the chances of pregnancy. The ideal technique should ensure that the swab enters the uterus and collects bacteria from only the uterine lumen and contamination with vaginal bacteria is prevented. It is important to ensure that the method of swabbing does not introduce bacteria into a previously normal uterus.
Almost every bacterial species may be isolated from a mare suffering from endometritis. The most common aerobic bacteria found in acute cases of endometritis are Streptococcus zooepidemicus, Escherichia coli, P. aeruginosa and K. pneumoniae. The most commonly found anaerobic bacteria assosiated with endometritis is Bacteroides fragilis.
A positive culture result, with no evidence of inflammatory
cells in the smear (usually neutrophils), is likely due to contamination during collection. Diagnosis of acute
endometritis is based on the presence or absence of significant numbers of inflammatory cells in the smear.
Endometrial biopsy provides information about the quality of the endometrial tissue and thus can aid in predicting the chances of a mare carrying a foal to term and may provide a basis for treatment.
A biopsy is usually taken from a site at the base of one of the uterine horns. It is important not to obtain a biopsy from a site near the interal os of the cervix to prevent adhesions of the cervix. Another reason not to take biopsies of this region is the small amount of glands present in this area making the sample less representative and more difficult to interpret.
One may take a biopsy sample at anu time during the year or during any time of the cycle because of the cervix of the mare is dilated easliy. It is very important to provide the pathologist information about the mare including the stage of the cycle the sample was taken.
Endometrial biopsies are classified into four categories:
Detection Of Intraluminal Uterine Fluid Using Ultrasound Imaging
Ultrasonography provides a rapid, non-invasive method of assessment of the uterus :1. If no free fluid is detected during estrus, then acute endometritis as detected in cytology is absent in 99% of cases.2. Free fluid does not indicate inflammation.
Ultrasound image of fluid in the uterus of a mare
3. Endometrial cytology and culture fail to detect sterile fluid accumulations.Therefore, in mares which are particularly susceptible to endometritis and where vaginal interference should be minimized, endometritis often can be diagnosed on the basis of fluid in the uterus. If fluid is seen in the uterus, or where there are signs of vulval discharge or a short luteal phase, swabs should be taken to determine the cause.Uterine Luminal Fluid-Since the identification of small volumes of intrauterine fluid general awareness of the frequency of this abnormality has increased. Endometrial secretions and the formation of the small volume of free fluid might be associated with the same mechanism that causes normal edema during estrus. In many cases, the uterine luminal fluid that accumulates before mating is sterile and contains no neutrophils. The importance of these sterile fluid accumulations to endometritis is that, although initially sterile, the fluid might act as a culture medium for bacteria to multiply that gain entry to the uterus at mating and could be spermicidal.The amount of fluid that should be considered significant is not clear, and it could be that quantity is more important than nature. This is particularly true of fluid appearing during estrus. The significance depends to some extent on when during estrus the fluid is observed: fluid detected early in estrus might disappear when the mare is further advanced in estrus and the cervix relaxes more. In the authors experience, small volumes of intrauterine fluid during estrus do not affect pregnancy rates in contrast to mares with larger (greater than 2 cm depth) collections of fluid.If there is more than one centimeter of fluid during estrus, you probably will make an attempt to remove the fluid (using oxytocin) prior to breeding. If the volume is more than two centimeters, the fluid might need to be drained and investigated for the presence of inflammatory cells and bacteria. The mare might need a large volume uterine lavage. Intrauterine fluid during diestrus is indicative of inflammation and associated with subfertility due to early embryonic death and a shortened luteal phase.
Detection Of The Susceptible Mare
This can be difficult as there might only be subtle changes in the uterine environment that are not readily detected by current diagnostic procedures. Many mares show no signs of inflammation before breeding, but fail to resolve the inevitable endometritis that follows breeding.History is perhaps the most useful indicator of a susceptible mare in practice. Demonstration of clearance failure using response to bacterial challenge and scintigraphic methods have been used to identify that a mare has a clearance problem, but they are difficult to apply in practice. Use of the ultrasound to detect uterine luminal fluid appears to be the most useful technique in practice.In the authors opinion, the presence of free intraluminal fluid prior to breeding strongly suggests susceptibility to persistent endometritis. It currently is not known for certain whether the fluid accumulates due to an excess production, a delay in physical clearance via the open cervix, or decreased reabsorption by lymphatic vessels. It might involve all three.
The third-generation cephalosporins have greater activity against beta-lactamase-producing Gram-negative bacteria, a wider spectrum of activity, lower minimum inhibitory concentrations for susceptible organisms, longer half-lives, and a greater ability to penetrate inflamed meninges than first- and second-generation cephalosporins. These antibacterials are widely distributed in the body and produce effective drug concentrations in pleural, pericardial and synovial fluid, cortical and cancellous bone, urine and bile. Antibacterial activity is excellent against Escherichia coli, Klebsiella, Citrobacter diversis, Proteus, Morganella and Enterobacteriaceae. There is some activity against Pseudomonas and Serratia, but they are ineffective against ethicillin-resistant Staphylococcus aureus. They are effective for treating resistant Gram-negative infections in compromised patients and Gram-negative meningitis. Adverse effects include gastrointestinal irritation, hypersensitivity, local pain and irritation at injection sites, hypoprothrombinemia, platelet dysfunction and a higher incidence of superinfection by enterococci or Candida. Of the third-generation cephalosporins, ceftiofur sodium (Naxcel: Upjohn) is approved for use in beef and dairy cattle and swine by IM injection. The fluoroquinolones are highly bioavailable after PO dosing and effective against Gram-negative and Gram-positive bacteria, mycoplasmas and chlamydiae. In particular, activity against Enterobacteriaceae, including Pseudomonas, is good. Resistance to the fluoroquinolones develops slowly. They are effective for treating resistant infections of the gastrointestinal and genitourinary tracts, Gram-negative respiratory tract infections, infections in bone, infections of the external auditory canal, and Gram-negative and possibly staphylococcal skin and soft tissue infections. Articular cartilage damage in puppies, foals, rats, mice and rabbits has occurred with use of relatively large doses of fluoroquinolones. Concomitant use of theophylline with fluoroquinolones may present problems. Presently, enrofloxacin (Baytril: Miles) is approved for dogs and cats at 5 mg/kg daily in 1 or 2 divided doses for 5-10 days.Orsini JA. Sch Vet Med, Univ Pennsylvania, Kennett Square, PA.Large Anim Veterinarian 48(8):13-14, 1993.
Antimicrobial susceptibility patterns for endometrial isolates
When 273 aerobic Gram-negative isolates from endometrial cultures collected from 522 mares were tested for susceptibility to antibiotics, gentamicin was active against 86% of E coli isolates, 65% of Klebsiella pneumoniae, and 33% of Pseudomonas aeruginosa; K pneumoniae was 100% susceptible to amikacin. E coli, P aeruginosa, K pneumoniae and Strep zooepidemicus accounted for 79.9% of all isolates. Cephalosporins have good activity against enterics but poor activity against P aeruginosa. Ticarcillin had better activity against E coli and P aeruginosa than did ampicillin, but both drugs had low activity against K pneumoniae. Because bacterial endometritis is routinely treated before culture results and antimicrobial susceptibility patterns are available, empiric selection of therapeutic agents must take into account resistance patterns of E coli, K pneumoniae and P aeruginosa. Penicillins and cephalosporins have high activity against streptococci, while ampicillin and ticarcillin are active against many strains of E coli and P aeruginosa. Aminoglycosides are used primarily against aerobic Gram-negative organisms, but resistance commonly develops to streptomycin and neomycin, and less commonly to gentamicin and amikacin. Bacteriostatic agents, such as chloramphenicol and tetracycline, should not be used because of possible resistance. Combinations of agents should be used with caution, as drug inactivation or reactions may occur.P.M. McCue et al. Sch Vet Med, Univ California, Davis.Antimicrobial susceptibility patterns for equine endometrial isolates. Calif Vet 45(1):23-26, 1991.
Postbreeding intrauterine infusion of ticarcillin
When 24 healthy mares were bred naturally and the uterus was infused 1 hr after each breeding with 6 g of ticarcillin (Ticar: Beecham) in 100 ml of normal saline or with saline alone, pregnancy rates were not significantly different (9 of 12 and 10 of 12, respectively). Sixteen mares conceived (8 from each group) during the first estrus. The mares were bred when a follicle >45 mm was present and again at 48-hr intervals until ovulation. Postbreeding antibiotic infusions are intended to reduce colonization of the uterus by bacteria introduced during breeding. The most common organisms are beta-hemolytic Strep, followed by E coli, Klebsiella pneumoniae, Staph aureus, Pseudomonas aeruginosa and Coryn spp. Ticarcillin is effective against most organisms that cause intrauterine infection, excepting Klebsiella. It reaches high concentrations in uterine tissues, is not affected by cellular debris, and does not adversely affect phagocytosis of neutrophils as aminoglycosides do. Ticarcillin also had no adverse effect. M.M. LeBlanc et al. Coll Vet Med, Univ Florida, Gainesville. The effect of intrauterine infusion of ticarcillin disodium one hour post-coitus in reproductively normal mares. Equine Pract 11(10):33-38, 1989.
Changing susceptibility of gram-negative organisms to gentamicin
To investigate resistance patterns among Gram-negative isolates, susceptibility of isolates to gentamicin and amikacin was evaluated from July 1983 to June 1985. All isolates of E coli, Enterobacter, Klebsiella, Proteus and Pseudomonas spp examined were susceptible to amikacin, except 2 of 46 Pseudomonas isolates. In contrast, 13-50% of isolates were resistant to gentamicin. E coli, Klebsiella, Proteus and Enterobacter spp isolates were significantly more susceptible to amikacin. Pseudomonas spp showed no significant difference in susceptibility. There was a significant variation among genera and their susceptibility to gentamicin, primarily because of the frequency of resistance in isolates of Klebsiella and Proteus spp as compared with the other 3 organisms (E coli, Enterobacter, Pseudomonas spp). There was no significant difference of susceptibility to amikacin among the genera studied. J.A. Orsini et al. Sch Vet Med, Univ Penn, Kennett Square. Changing susceptibility patterns of Gram-negative organisms to gentamicin sulphate in horses.Proc Ann Mtg ACVS 24:75, 1989.
Gram-negative bacterial resistance
Of Gram-negative isolates, including E coli, Enterobacter spp, Klebsiella spp, Proteus spp and Pseudomonas spp, all except 2 Pseudomonas isolates were susceptible to amikacin. Gentamicin resistance was high among the isolates in all genera. Pseudomonas spp were not significantly different in susceptibility to the 2 drugs; however, E coli, Klebsiella, Proteus and Enterobacter isolates were significantly more susceptible to amikacin. Klebsiella and Proteus spp had higher rates of resistance to gentamicin than did E coli, Enterobacter and Pseudomonas. There were no significant variations among genera in their susceptibilities to amikacin. J.A. Orsini et al. Sch Vet Med, Univ Pennsylvania, Kennett Square. Resistance to gentamicin and amikacin of Gram-negative organisms isolated from horses.Am J Vet Res 50:923-925, 1989.
Uterine clearance of bacteria
After the uteri of 12 seasonally anestrous maiden mares were inoculated with Strep zooepidemicus, the 4 mares given 150 mg progesterone (Group P) SID for 25 days had more purulent uterine fluid, with more bacteria and IgA, after 7 days than 4 given 10 mg estradiol-17B (Group E) SID for 25 days or 4 controls (Group C). Clearance began within 2 hr in Group E, and nonantigenic markers were cleared by day 3 in Groups E and C. Differences between Groups P and E were attributed to differences in uterine drainage and physical clearance, which was decreased in older mares. Progesterone increases uterine and cervical tone, inhibits uterine contraction and results in secretion of very viscous mucus, which tends to slow uterine emptying and predispose to infection, while estrogen has the reverse effects. Other factors affecting uterine susceptibility include status of cellular and noncellular defense mechanisms, Ig production and transport, parity, degree of foaling trauma, conformation or hereditary factors and the pathogenicity of organisms. Bacterial uterine contamination occurs in >80% of mares 24 hr after service and up to 30 days postpartum, but is transient in normal mares with concurrent transient endometrial inflammation. Bacterial recovery from the uterus does not indicate an established infection since contamination is common, but mares with positive cultures tend to have reduced fertility. B-hemolytic strep is most frequently encountered, but E coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staph aureus are also common. M.J. Evans et al. Dept Vet Sci, Lincoln Coll, New Zealand. Clearance of bacteria and non-antigenic intra-uterine inoculation into maiden mares; Effect of steroid hormone environment.Theriogenology 26:37-48, 1986.
If all stallions on a farm are low, all parts of the breeding system that are common to all stallions should be investigated. This would include the following factors: semen extender, lube, disinfectants, mare care, mare condition, insemination equipment, insemination technique, timing of insemination, and the like. If only one or a few stallions are involved, just those stallions need to be investigated. Causes could include recent fever, low inherent fertility, overuse of a marginal stallion (inadequate artificial insemination dose), Klebsiella or Pseudomonas, unilaterally plugged ampulla, a book of predominately old mares, and so on.
Pseudomonas and the Role of the Stallion Penis in Equine Genital Infections
Unfortunately, the epidemiology of Pseudomonas colonization of the stallion penis is poorly understood. Although the organism seems to be ubiquitous in many horse environments, we do not know which predisposing factors facilitate its ability to colonize and persist in the endometrium or on the penis. Colonization of the penis refers to that state in which the bacterial flora of the penis is dominated by P. aeruginosa. A< few colonies of P. aeruginosa mixed in with the general penile flora appear to present no serious problems. Washing of the penis with soap or disinfectants may 8 or may not 9 predispose to the penis becoming colonized. Veterinarians and others involved with breeding mares have great respect for P. aeruginosa when it is the cause of endometritis. The respect is based on the difficulty often encountered in permanently eliminating this organism from the uterus once it has become established. Furthermore, the infected mare is a threat to the stallion. While P. aeruginosa can cause a moderate to severe endometritis, the colonized penis is lesionless. It is generally felt that a stallion penis colonized by this organism is a constant threat to the mares bred by the stallion, yet it is really only the occasional mare under this constant threat that becomes infected, thereby emphasizing our ignorance of predisposing factors. This threat to the mare can be considerably reduced, if not eliminated, by holding the semen in an antibiotic-containing extender before breeding artificially 4, 10-13 or by the infusion of an antibiotic-containing extender into the mares uterus before natural service. 10, 13 As far as causing internal genital infections of the stallion, we have detected only one case caused by P. aeruginosa out of over 2, 500 stallions examined. 4 This stallion maintained the infection in its seminal vesicles and ampullae for over 10 years in spite of many attempts and considerable expense to treat it systemically and locally. The offending organism was not serotypable. A comparison of breed versus incidence of the organism in mares and stallions (Table 1) indicates that in our series of cases, Pseudomonas is isolated most frequently from the genitalia of the Thoroughbred stallion. This finding is difficult to interpret because of the variety of reasons for cases coming to this clinic. However, it may be caused by repeated washing of the penis and exposure to mares during live cover or more thorough scrutiny by farm veterinarians. 11. Simpson RB, Burns SJ, Auell JR. Microflora in stallion semen and their control with a semen extender, in Proceedings. 21st Annu Conv Am Assoc Equine Practnr 1975;255.12. Squires EL, McGlothlin DE, Bowen RA, et al. Use of antibiotics in stallion semen for the control of Klebsiella pneumoniae and Pseudomonas aeruginosa. Equine Vet Sci 1981;1(2):43-48.13. Blanchard TL, Varner DD, Love CC, et al. Use of a semen extender containing antibiotic to improve the fertility of a stallion with seminal vesiculitis due to Pseudomonas aeruginosa.Theriogenology 1987;28(4):541-546. --------------------------------------------------------------------------------Theriogenology 1998 Oct 15;50(6):821-31Concentrations of total protein, albumin and immunoglobulins in undiluted uterine fluid of gynecologically healthy mares. Tunon AM, Rodriguez-Martinez H, Hulten C, Nummijarvi A, Magnusson U Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, SLU, Uppsala, Sweden.Undiluted uterine fluid from 20 Warmblood/Standardbred mares (5 to 14 yr old) was recovered by absorption to an intrauterine tampon. The mares were considered gynecologically healthy based on a clinical examination including uterine swabs for cytology and bacteriology as well as endometrial biopsy examinations. The protein profiles (SDS-PAGE) and concentrations of total protein, albumin, and immunoglobulins (Ig) A and G in the uterine fluid were examined and compared with the same proteins in serum. Major peaks were identified on the obtained protein profiles, and there was a clear similarity between the serum profiles and uterine fluid profiles. Variability in protein concentrations among mares was considerably larger in uterine fluid than in serum. Concentrations of the various proteins in uterine fluid were 44 to 56% of those in serum, except for IgA, which had a similar concentration in both serum and uterine fluid. Concentration of the proteins corresponding to peak No. 3 (molecular weight 60 to 71 kDa) in uterine fluid was higher (P < 0.05) in younger mares than in older ones. Parity had no effect on the recorded protein concentrations. The present study of gynecologically healthy mares showed that there is a large individual variation in the protein composition of uterine fluid. The results suggest that age, but not parity, may affect this composition, and indicate further that there is considerable transudation to the uterine cavity.--------------------------------------------------------------------------------Cell proliferation patterns in the equine endometrium throughout the non-pregnant reproductive cycle.Immunohistochemical detection of the proliferation marker Ki-67 antigen was used to monitor mitotic activity in the endometrium of mares. The monoclonal antibody MIB1 was validated for use on equine tissues by demonstrating its reaction with activated peripheral blood lymphocytes, and endometrial biopsies were recovered from 26 non-pregnant mares at selected stages during the reproductive cycle. The proportion of positively stained nuclei was counted in five random areas on each histological section to determine the percentage and type of proliferating cells. Multiplication rates in the types of cell found in the superficial strata, comprising the luminal epithelium, the epithelium of the gland necks and the stromal cells of the stratum compactum, were greatest during oestrus, presumably under the influence of oestrogens secreted by the growing ovarian follicles. In contrast, the mitotic activity in the cells of the deeper secretory portions of the endometrial glands was restricted to a brief phase between day 3 and day 7 of dioestrus, most likely as a delayed response to the decreasing oestrogen concentrations after ovulation. Some of the degenerate glands in subfertile mares did not follow this pattern of increased epithelial proliferation at that stage. After day 7 of dioestrus, the proliferation rates of cells in the endometrium decreased to basal values and remained low for as long as progesterone concentrations remained evaluated, even during prolonged dioestrus. The technique enabled characterization of normal cell proliferation patterns in the endometrium of mares and it will be a useful tool in the future for monitoring the endometrial responses of reproductively healthy and subfertile mares. University of Cambridge Department of Clinical Veterinary Medicine, Newmarket, Suffolk, UK.- J Reprod Fertil 1999 May;116(1):167-75 Clinical significance of aerobic bacterial flora of the uterus, vagina, vestibule, and clitoral fossa of clinically normal mares.Hinrichs K, Cummings MR, Sertich PL, Kenney RMSwab specimens for bacterial culture were obtained from the uterus, vagina, vestibule, and clitoral fossa of 48 mares that had normal reproductive tracts, no history of reproductive problems, and no inflammation on evaluation of endometrial biopsy. The mares were predominantly Thoroughbred and Standardbred. Swab specimens of the vagina were obtained through a sterile speculum; swab specimens of the uterus were obtained by use of a double-guarded, occluded culture instrument. Fifteen (31%) of the uterine swab specimens and 20 (42%) of the vaginal swab specimens yielded growth on aerobic culture; however, only 2 (4%) of the uterine swab specimens and 4 (8%) of the vaginal swab specimens yielded growth of more than 10 colonies. In contrast, 21 (44%) of the vestibular swab specimens and 45 (94%) of the clitoral fossa swab specimens had moderate (greater than 10 colonies in 1 quadrant) to heavy (colonies in 2 or 3 quadrants) growth of organisms on culture. Of organisms considered to be potential pathogens, Streptococcus zooepidemicus and Escherichia coli were found on bacteriologic culture of several clitoral fossa swab specimens and of some vestibular swab specimens. We did not isolate any potential pathogens from uterine or vaginal swab specimens. It appears that 1 to 10 colonies of nonpathogenic organisms could be recovered from the uterus in a substantial number of clinically normal mares even when double-guarded swabbing techniques are used, and we suggest that prebreeding culture requirements be modified to reflect this. Also, our findings indicate that the vulvovaginal fold, rather than the cervix, might be the major barrier to ascending bacterial contamination of the reproductive tract. --------------------------------------------------------------------------------Videoendoscopic evaluation of the mare's uterus: II. Findings in subfertile mares.Equine Vet J 1992 Jul;24(4):279-284Bracher V, Mathias S, Allen WRVideoendoscopy of the reproductive tract was performed in 87 Thoroughbred mares with histories of reduced fertility. During hysteroscopy samples for cytological, microbiological and histological examinations were obtained under visual control. Common findings in these broodmares included: (a) endometrial degeneration, as assessed by an uneven distribution or atrophy of endometrial folds and/or a scarred appearance of the endometrium (49 mares, 56%); (b) endometrial cysts of various sizes and locations within the uterus with the most common location being at the base of the uterine horns (48 mares, 55%); (c) fluid accumulation in the uterine lumen (28 mares, 32%). A few mares had transluminal adhesions (7 mares, 8%) and in 2 mares the adhesions appeared to obstruct one uterine horn completely. A solitary discrete lump was detected in the wall of the uterine body in one mare and the suspicion of it being a leiomyoma was confirmed histologically with the aid of a visually directed biopsy sample. Free intraluminal structures were present in the uterine lumen in 3 mares, including one inspissated blood clot and two suspected remnants of resorbing pregnancies. Flexible biopsy forceps and scissors passed through the working channel of the endoscope were used to sever small thin adhesions, but this method proved inadequate for multiple adhesions or cysts. Solitary endometrial cysts were removed by means of conventional rigid biopsy forceps passed alongside the endoscope, although bleeding from the operation site usually limited this type of intervention. Equine Vet J 1992 Jul;24(4):274-278 --------------------------------------------------------------------------------Videoendoscopic evaluation of the mare's uterus: I. Findings in normal fertile mares.Bracher V, Allen WRThe 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. Zentralbl Veterinarmed [A] 1993 Oct;40(8):569-575 --------------------------------------------------------------------------------The relationship between cycle stage and results of uterine culture in the mare.Waelchli RO, Kanzig M, Gygax A, Corboz L, Rusch PA total of 368 uterine swabs were taken from mares in heat (n = 202) and from mares that were not in heat (n = 166). From 72 of the mares, two swabs were taken; one during either seasonal anoestrus or dioestrus, and one during oestrus. Swabs were taken during anoestrus/dioestrus in 94 other mares and during oestrus in the remaining 130 mares. Bacteriological cultures were done aerobically and classified as negative, insignificant or significant. There was a trend for more positive cytological specimens during oestrus than during anoestrus/dioestrus. The proportions of significant cultures were 12 of 202 (5.9%) in oestrous mares and 14 of 166 (8.4%) in anoestrous/dioestrus mares. Generally more insignificant than negative cultures were obtained during oestrus compared to anoestrus/dioestrus. Seven of 27 cultures that were classified as significant were associated with positive cytological specimens, and only 2 of 16 specimens that yielded pure cultures of E. coli contained neutrophils. Although the culture results did not differ significantly between the cycle stages, oestrus should be the preferred time for uterine examination.J Am Vet Med Assoc 1992 Aug 1;201(3):438-440 --------------------------------------------------------------------------------A quantitative study of the histological morphology of the endometrium of normal and barren mares.Leishman D, Miller RB, Doig PAThe density of uterine glands, height of surface epithelium, numbers of hemosiderin laden macrophages, inflammatory cells and layers of periglandular fibrosis were evaluated in uterine biopsies from 40 mares. These features were found to be highly variable in normal equine endometrium. Minor pathological changes appeared to be masked by this normal variability. Atrophy of uterine glands was recognized in mares which had been barren for more than three years. No significant differences were found between barren and normal mares in the height of epithelium, number of hemosiderin laden macrophages, inflammatory cells or layers of collagen surrounding glands in the superficial portion of endometrium. The number of layers of fibrosis surrounding glands in the deep part of lamina propria were found to be correlated with years of barrenness. This finding appears to have prognostic potential.Equine Vet J 1996 Nov;28(6):455-460 --------------------------------------------------------------------------------Histomorphological endometrial status and influence of oxytocin on the uterine drainage and pregnancy rate in mares.Rasch K, Schoon HA, Sieme H, Klug EThe aim of this field study was to examine the influence of the uterotonic substance oxytocin in 2 different therapeutic dosages of 15 and 25 i.u., respectively on the uterine drainage of oestrous mares and on their fertility. In addition endometrial biopsies of mares with and without intrauterine fluid accumulations around the time of ovulation were evaluated histomorphologically regarding the aetiology of susceptibility to uterine infection. A population of 59 Hanoverian Warmblood mares was used in this study. The mares were divided into Group A (mares with intrauterine fluid accumulations [n = 49]) and Group B (controls [n = 10]). Group A was further subdivided into 3 groups according to varying oxytocin administrations (none, 15 i.u., 25 i.u.). Prior to insemination, all mares were examined by rectal palpation, ultrasonography and vaginal inspection. In addition, hormone plasma concentrations were evaluated at the time of ovulation, namely oestradiol and progesterone concentrations. Endometrial biopsies were obtained from all mares. Endometrial samples for microbiological and cytological evaluation were taken from mares of Group A only. All mares were inseminated close to ovulation during the first cycle. This study shows that intravenous oxytocin treatment of mares with intrauterine fluid accumulations results in better pregnancy rates (In 1997 researched showed that adding intrauterine antibiotics 30 minutes post oxytocin, further increases pregnancy rates...RNO) than no treatment. J Am Vet Med Assoc 1988 Jul 1;193(1):72-75
- Abnormal length of estrus period, heat
- Mucous discharge, vulvar, vaginal
- Purulent discharge, vulvar, vaginal
- Purulent or mucoid discharge, cervix or uterus
- Adhesions, uterus, ovary, cervix
- Female infertility, repeat breeder
Correct Predisposing Factors
Culture and sensitivity should guide antimicrobial treatment. Since treatment should begin as soon as possible, characterization of the infective organism by gram staining of the uterine cytology swab can be done prior to culture and sensitivity results. The minimal intrauterine treatment duration is 3 days, the average is 5 days and in some cases 7-10 days may be desired. once daily intrautreine infusions are adequate.
ANTIBIOTICS FOR INTRAUTERINE INFUSION
ANTIMICROBIALS USED SYSTEMATICALLY TO TREAT ENDOMETRITIS
Post Breeding Endometritis
The following protocol for mares who have been identified with this problem, has been recommended and supercedes the older recommendations that recommend post ovulation monitoring:
Pre Breeding Washing of Mares and Stallions
Poor Perineal Conformation