IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE

Post-Partum Problems: The Top Ten List

Regina M. Turner, VMD, PhD, Diplomate ACT

This article reviews the top ten post-partum problems in mares. The problems are broadly broken down into two main categories: those that cause pain or systemic illness and those that do not. Problems resulting in pain or systemic illness include: septic metritis, hemorrhage from uterine or ovarian vessels, gastrointestinal problems/colic, uterine laceration and uterine horn intussusception/ uterine prolapse. Issues in systemically healthy mares include: retained fetal membranes, post- Cesarean section management, post-dystocia management, hypogalactia/agalactia, and urovagina/ urometra. For each topic, practical management and treatment options are presented and the prognosis for future reproductive success is discussed. Author’s address: New Bolton Center, De- partment of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 382 West Street Road, Kennett Square, PA 19348; e-mail: [email protected]. © 2007 AAEP.

1. Introduction tion. Using these data as a starting point, this Problem post-partum mares often fit into one of two manuscript will review the most common findings in broad categories: mares presenting as painful or mares presenting with one of the top five causes for systemically ill and mares presenting as systemi- post-partum pain or systemic illness. Common cally healthy but with post-partum problems that treatment options will be reviewed, and prognosis can affect their future wellbeing and/or fertility. for recovery and future reproductive success will be The objective of this manuscript is to review the discussed. most common problems seen in these mares and to review practical management and treatment op- 1. Septic Metritis tions for their problems. Additionally, prognosis Post-partum metritis can vary in severity. In its for future reproductive success will be described. worst form, toxic metritis can be life threatening, particularly if the affected mare becomes laminitic. 2. The Post-Partum Painful/Systemically Ill Mare The first broad group of problem mares are those Signalment/History with pain or systemic illness as the presenting com- Septic metritis can affect mares of any age or parity. plaint. In these cases, components of the general History often includes dystocia and retained fetal workup include signalment/history, general physi- membranes. cal examination, clinical hematology and chemistry evaluation, abdominocentesis, palpation and ultra- Physical Examination sonography of the reproductive tract per rectum, Mares may present with classic signs of endotox- manual examination of the reproductive tract per emia. Most are tachycardic. Fever is often vagina, and abdominal ultrasonographic examina- present, and in severe cases, the mare’s mucous

NOTES

AAEP PROCEEDINGS ր Vol. 53 ր 2007 305 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE membranes may seem toxic. Malodorous vaginal Prognosis for Future Reproductive Success discharge may be noted. In most cases, there is an underlying cause for the Clinical Hematology and Chemistry metritis (retained membranes or dystocia). As such, barring these problems in the future, recov- The most common hematology and chemistry eval- ered mares often can be bred again and conceive uation findings are leukopenia and hyperfibrinogen- with no increased risk of developing septic metritis emia. Less often, leukocytosis is a finding. after subsequent parturitions. Because metritis Abdominocentesis typically causes delayed uterine involution, one may need to delay rebreeding the mare until involution is Abdominocentesis is often normal unless a concur- complete.2 In general, allowing the mare to have rent uterine laceration is present. one estrous after complete resolution of the metritis Palpation and Ultrasonography of the is usually sufficient. A complete breeding sound- Reproductive Tract per Rectum ness examination may be prudent before rebreeding these animals Palpation and ultrasonography of the reproductive tract per rectum usually finds an atonic, poorly in- 2. Hemorrhage From Uterine or Ovarian Vessels voluted uterus. Often, intrauterine fluid is present Hemorrhage from uterine or ovarian vessels typi- together with fetal membranes. cally occurs during parturition, and problems be- Examination of the Reproductive Tract per Vagina come obvious in the immediate post-partum period. Less commonly, hemorrhage may occur during preg- Malodorous uterine fluid is usually present, and fe- nancy or up to several days post-partum.5–7 Most tal membranes are often retained. cases involve rupture of the middle uterine artery Abdominal Ultrasonographic Examination (MUA), utero-ovarian arteries, or external iliac ar- teries.6 Older, multiparous mares are at greatest The abdominal ultrasonographic examination is risk.7,8 It is possible that mild cases of MUA rup- usually non-remarkable unless a concurrent uterine ture may go undiagnosed if the mare does not show laceration is present. clinical signs. However, in moderate to severe Treatment cases, clinical signs are often apparent. The spe- cific signs of this problem can vary, often depending Treatment includes administration of broad-spec- on where the rupture occurs. trum antimicrobials such as potassium penicillina b (22,000 IU/kg, q6 h, IV) and gentamicin sulfate (6.6 Signalment/History mg/kg, q 24 h, IV) and administration of flunixin megluminec (1.1 mg/kg) both for its anti-inflamma- Older, multiparous mares are at higher risk. Often, tory and anti-end toxic effects. If fetal membranes the delivery is uncomplicated. The mare may have a are present, oxytocin therapy is initiated (see section past history of post-partum hemorrhage. on retained fetal membranes for dosages and dosing Physical Examination intervals). Even if membranes are not present, oxytocin may be used in conjunction with large- Severe tachycardia is a common finding, usually volume intrauterine saline lavage to help clear the associated with either pain, hemorrhage, or both. uterus of fluid and debris. Large-volume lavage Pale mucous membranes are suggestive of a MUA typically requires a minimum of3lofsaline and bleed. However, membrane color may be normal may require many more (up to 15 l or more) to be during the acute phase. Classic general signs of effective. Typically, we will continue to lavage un- hemorrhage from the reproductive tract include til the effluent recovered is clear. Additional anti- sweating, flehmen, vocalization, and muscle fascicu- endotoxin therapy may include equine plasma lations. When the artery ruptures such that hem- polymixin B (1.5 million IU/550 kg horse diluted and orrhage occurs into the uterus, the mare may administered slowly, q 12 h, IV for 3 days)d and/or present for colic associated with uterine distension. pentoxifylline (7.5 mg/kg, q 12 h, PO).e1 Affected Alternatively, rupture can occur such that hemor- mares should be monitored carefully for the devel- rhage is in the broad ligament. In these cases, pain opment of laminitis,2–4 and treatments designed to is often more apparent in association with stretch- prevent the development of laminitis (such as icing ing of the broad ligament. Lastly, rupture can oc- of the hooves and stabling the mare on soft footing cur into the abdominal cavity. These mares often such as shavings or sand) should be instituted. are less painful, but they may bleed more profusely and may be at greater risk for sudden death because Prognosis for Systemic Recovery of uncontrolled hemorrhage. If complications of metritis (e.g., laminitis and peri- tonitis) can be avoided, the prognosis for systemic Clinical Hematology and Chemistry recovery is good. Development of complications Interestingly, complete blood counts in the acute will lower the prognosis. In its worst form, septic phase of hemorrhage may show an increase, de- metritis can be life threatening. crease, or no change in packed cell volume (PCV).

306 2007 ր Vol. 53 ր AAEP PROCEEDINGS IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE This is most likely caused by splenic contraction, mg/kg IV alone or in combination with xylazine,g 0.4 hemoconcentration, and redistribution of red cells. mg/kg) and anti-inflammatory drugs (e.g., flunixin) Hypoproteinemiaisamoreconsistentfinding. How- typically are administered to improve the mare’s ever, if the mare survives the acute phase, a drop in comfort and reduce distress. Acepromazine is to be PCV usually is observed over the next several days. avoided because of its hypotensive effects.2 As soon as is practical, the mare is placed in a quiet stall, Abdominocentesis often with the doors and windows closed to minimize Mares with hemorrhage into the abdomen or into disturbances, and the “wait and see” approach is the broad ligament often have significantly in- taken. In more desperate situations, blood trans- creased numbers of red blood cells (RBCs) in abdom- fusions and/or hypertonic saline may be inal fluid. administered. IV naloxoneh may be administered (0.01–0.02 mg/ Palpation and Ultrasonography of the kg), because there are anecdotal reports that sug- Reproductive Tract per Rectum gest that this may improve survival in This may be diagnostic, because large hematomas hemorrhaging mares. In other species, it has been can often be identified in the uterine wall or in the suggested that the mechanism of action of this opi- broad ligament. Alternatively, or in addition to oid antagonist is to provide analgesia and reverse these hematomas, blood may be present within the hypotension in cases of hemorrhagic shock.9,10 uterine lumen. However, in some instances (e.g., In the horse, practitioners often describe a decrease when hemorrhage is in the abdomen), a discrete in anxiety and an increase in comfort in mares after hematoma may not be identified, and per rectum administration of the drug. This may be caused by examination may be unrewarding. naloxone’s opioid-like effects when administered at Examination of the Reproductive Tract per Vagina subclinical doses. However, its effects in hemor- rhaging horses have not been tested in controlled If hemorrhage is suspected based on other clinical studies, and therefore, its use in affected mares re- signs, examination per vagina typically is not per- mains controversial. formed. It is our concern that manipulation of the IV formalin (16 ml of 10% buffered formalin di- uterus could dislodge or break down a clot and there- luted in 45 ml of 0.9% saline solution and adminis- fore, result in fresh hemorrhage. If it is performed, tered intravenously slowly) has also been used to frank blood may be identified in the uterus and treat uncontrolled hemorrhage in horses.11 It vagina if the hemorrhage is intrauterine. seems doubtful that either naloxone or formalin Abdominal Ultrasonographic Examination have a significant impact on the bleeding. On one Abdominal ultrasonographic examination is usually hand, naloxone seems to do no harm. On the other unremarkable, and as such, it is often not performed hand, formalin has been shown to have adverse side effects, at least when injected intralesionally into if there is other strong evidence for hemorrhage. 12 There may be an impression of increased abdominal hematomas. Additionally, one controlled study fluid and/or an increase in echogenicity of the ab- found no beneficial effect of the administration of IV dominal fluid in cases of severe hemorrhage. formalin on hemostatic variables in healthy hors- es,13 whereas more limited evidence has identified Treatment no beneficial effect on bleeding.14 i When MUA rupture is suspected, it is our policy to Oxytocin (40 IU, q 0.5 h, intrauterine) has been suggested as a treatment for hemorrhage associated minimize stressful procedures to the mare in an 15 attempt to lower blood pressure and prevent a po- with the myometrium. However, because it is of- tentially terminal bleed. Many portions of this ex- ten impossible to determine with certainty the exact amination (e.g., examination per rectum and per location of the rupture and because oxytocin may vagina, abdominocentesis, and abdominal ultra- cause cramping, further discomfort, and an associ- sonographic examination) are brief and sometimes, ated increase in heart rate and blood pressure, we are not performed at all. typically do not use this drug. When a diagnosis of MUA rupture is made, the Laparotomy can be considered in an attempt to clinician is often faced with the difficult decision of ligate the bleeding vessel. However, anesthesia whether or not to institute aggressive treatments and subsequent surgery present significant risks to that may increase the mare’s stress and blood pres- these animals, and it is not uncommon for affected sure and therefore, increase the risk of severe hem- mares to die during surgery. Additionally, the size orrhage and death. The alternative is to keep the of the mare’s abdomen, the position of the uterus mare in as peaceful a situation as possible and hope within the abdomen, and the problems associated for spontaneous clotting before the mare reaches a with visualizing the offending vessel in the face of critical level. In most instances, as a minimum, we ongoing and severe bleeding can make ligation of the will place an indwelling venous catheter and begin problem vessel difficult at best and sometimes im- the mare on volume replacement fluid therapy. possible. In our hands, surgery is rarely Analgesics (e.g., butorphanol tartrate,f 0.01–0.02 attempted.

AAEP PROCEEDINGS ր Vol. 53 ր 2007 307 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE If the mare’s condition stabilizes, we typically rec- the small colon, mesocolon, or small intestine), it can ommend that the mare remain in a stall and not be be very difficult to determine if the primary prob- transported for at least 2–4 wk after cessation of the lems lies within the reproductive tract or within the bleeding. This is intended to give the clot time to gastrointestinal tract. In these cases, a definitive form and stabilize. It has been reported that sud- diagnosis may require laparotomy. den death may occur even weeks after the initial bleed. This is likely caused by rupture of a hema- Signalment/History toma (e.g., that was previously contained within the In most instances, the signalment and history are broad ligament) or dissolution of a previously not remarkable. It is possible that dystocia may formed clot.7 result in an increased incidence of rectal prolapse Prognosis for Systemic Recovery (because of persistent straining) and also may in- crease the risk of trauma to the gastrointestinal The prognosis for recovery is variable, depending on tract. the severity of the hemorrhage. Mild hemorrhage into the broad ligament typically is associated with a good prognosis for recovery. However, severe hem- Physical Examination orrhage into the abdomen or uterus can be acutely Findings will depend on the source of the gastroin- fatal. It is the author’s impression that bleeding testinal problem. Cecal rupture typically presents into the broad ligament may be associated with a within 24 h of parturition.1 As a result of severe better prognosis for survival, because the limited peritonitis, affected mares typically present with volume that this space can hold may result in pres- tachycardia, depression, hypovolemia, and toxic sure that permits clotting and thus, limits bleeding. membranes. Body temperature may be elevated or However, even when hemorrhage is initially con- low. Rectal prolapse is readily diagnosed by visu- tained by the broad ligament, it is possible that the alization of the prolapse on physical examination. ligament may lacerate, resulting in massive, acute The classic sign of large-colon volvulus is acute, se- hemorrhage into the abdomen. vere abdominal pain. Physical findings in cases of trauma to the gastrointestinal tract are more vague Prognosis for Future Reproductive Success and often are associated with progressive peritoni- If the mare survives the episode, the question is tis. Signs may include depression, mild colic, often raised as to whether or not she should be bred tachycardia fever, decreased gastrointestinal motil- again. Hemorrhage from the reproductive tract ity, and gastric reflux.1 does not adversely affect fertility, and therefore, af- fected mares are likely to become pregnant if bred Clinical Hematology and Chemistry again. However, experience in our clinic strongly Clinical hematology and chemistry usually find suggests that mares that have suffered a post-par- hemoconcentration with hypoproteinemia, leukope- tum bleed are at greater risk for experiencing addi- nia, and azotemia in the case of cecal rupture. tional hemorrhages in subsequent parturitions. Trauma to the intestine or colon, in some cases, is Additionally, these subsequent bleeds often become indicated by leukopenia or leukocytosis, hyperfibri- more severe each year and may eventually result in nogenemia, hemoconcentration, and azotemia. In death of the mare. Owners should be made aware cases of peritonitis, hypoproteinemia may be of this risk before breeding the mare again. Em- identified.1 bryo transfer is an excellent alternative when breed registries permit. Palpation and Ultrasonography per Rectum 3. Gastrointestinal Problems/Colic In some cases, large-colon volvulus can be diagnosed Post-partum mares seem to be at increased risk for on palpation per rectum. In others cases, examina- several types of gastrointestinal problems. These tion per rectum is non-diagnostic. This condition include cecal rupture, rectal prolapse, trauma to the typically is extremely painful, and the mare’s behav- small colon or mesocolon, trauma to the small intes- ior may preclude palpation per rectum, rendering it tine, and large-colon volvulus.1,16–19 Trauma to impossible or at the least unsafe. In these in- the small colon or small intestine may result in stances, the decision to proceed to a laparotomy is ischemic bowel necrosis.17–20 The source of this often made based solely on the mare’s severe, unre- trauma is speculative and has been suggested to lenting pain. Diagnosis can then be made during involve pressure placed on the bowel by the position laparotomy. In cases of trauma to the small intes- of the fetus in utero. Alternatively, acute trauma tine, small-intestinal distension may be present. to the bowel could be caused by violent movements However, in many cases of trauma to the gastroin- of the foal’s extremities during parturition. In testinal tract, findings on palpation per rectum are some cases (e.g., rectal prolapse and large-colon vol- non-diagnostic. Palpation and ultrasonographic vulus), gastrointestinal problems can be readily dif- examination of the reproductive tract typically re- ferentiated from primary reproductive-tract veals a normally involuting uterus with no apparent problems. However, in other cases (e.g., trauma to problems.

308 2007 ր Vol. 53 ր AAEP PROCEEDINGS IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE Palpation of the Reproductive Tract per Vagina prolapsed tissue. In cases of trauma to the gastro- When a gastrointestinal problem is obvious, this intestinal tract, the prognosis depends on the dura- tion and degree of bowel-wall necrosis and procedure typically is not warranted. However, in 1 cases in which there is difficulty in determining secondary peritonitis. Dolente summarized a se- whether or not the primary problem is reproductive ries of case reports involving post-partum mares or gastrointestinal in origin, examination of the re- with small-colon trauma and reported only a 36% productive tract per vagina can be helpful. When survival to discharge. It is possible that this poor faced with a systemically ill mare but an apparently outcome may in part be caused by the difficulty in normal post-partum reproductive tract with no ob- diagnosing the problem. This often leads to delay vious uterine or vaginal lacerations, the veterinar- in surgical intervention. Perhaps earlier surgical ian should begin to consider a primary intervention would improve the outcome. gastrointestinal problem as a higher likelihood. Prognosis for Future Reproductive Success Abdominocentesis In cases in which the mare recovers from the gas- Abdominocentesis usually finds severe fecal perito- trointestinal incident and assuming that the repro- nitis in the case of cecal rupture. Trauma to the ductive tract was normal, fertility should not be colon or intestine is usually indicated by non-septic compromised, and the mare would likely be at no or septic peritonitis, and increased total protein may increased risk for primary reproductive problems in be present. subsequent foalings. The possibility of recurrent colic remains, particularly if treatment involved sur- Abdominal Ultrasonographic Examination gical intervention. This information may be helpful in determining whether or not an affected mare has peritonitis and 4. Uterine Lacerations to help rule out other, less frequent causes of post- In the vast majority of cases, uterine lacerations partum abdominal pain. We typically perform occur secondary to a dystocia. These lacerations transabdominal ultrasonographic examination of may be sustained when the mare strains persis- the abdomen only when other diagnostic tests have tently against an obstruction, when a fetal extrem- not led us to a definitive diagnosis. ity pushes through the uterus or vagina, or after blunt trauma to or pressure on the uterine wall from Miscellaneous a fetal extremity.22 Alternatively, they can be Identification of a piece of compromised or necrotic caused iatrogenically by overly aggressive manipu- bowel can be very difficult, particularly if overt peri- lations of a fetus or secondary to a fetotomy. Less tonitis is not yet present. It is often difficult or frequently, lacerations can be sustained as part of impossible to definitively differentiate between a an otherwise apparently normal delivery. It is compromised bowel and a uterine laceration, partic- strongly recommended that the mare’s reproductive ularly if the mare is recently post-partum and the tract be examined immediately post-partum, partic- uterus is too large to exam in its entirety per vagina. ularly after a dystocia, to attempt to identify a lac- Definitive diagnosis may require laparotomy or eration early before secondary complications laparoscopy.18 develop. Early diagnosis of a uterine laceration is critical to Treatment a successful outcome. If identified early, contami- Treatment will vary depending on the cause. Cecal nation of the abdominal cavity can be minimized, rupture carries a grave prognosis, and euthanasia is and the mare can be placed prophylactically on an- recommended.1 Treatment of rectal prolapse cen- tibiotics (e.g., potassium penicillin and gentamicin ters around the reduction of the prolapse. Admin- sulfate) and anti-inflammatories (e.g., flunixin me- istration of epidural anesthesia can greatly facilitate glumine) to minimize the risk of septic complica- this procedure. In severely affected cases, the tions. Unfortunately, many of these mares present small colon may be involved, and exploratory sur- several days post-partum after they have already gery may be indicated.21 After the prolapse is re- sustained significant abdominal contamination. placed, subsequent treatment will depend on the In these cases, the prognosis for survival is lower, amount of damage sustained by the prolapsed tis- and the cost of treatment is higher. The purpose of sues. Correction of large-colon volvulus requires this section is to emphasize how to diagnose this laparotomy. problem early and therefore, avoid systemic illness associated with secondary peritonitis. Prognosis for Systemic Recovery The outcome of these cases varies widely depending Signalment/History on the underlying cause. Cecal rupture carries a Mares can be of any age or breed. Dystocia is very grave prognosis. The prognosis with rectal pro- frequently part of the history, although lacerations lapse is variable, depending on the degree of pro- can sometimes be sustained even during an appar- lapse and the amount of damage sustained by the ently normal delivery.23–26

AAEP PROCEEDINGS ր Vol. 53 ր 2007 309 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE Physical Examination palpation of the uterus, the size of the uterus imme- In the acute stage, before significant abdominal con- diately post-partum often makes it impossible to tamination has occurred, there may be no obvious reach the tips of the uterine horns, particularly in outward clinical signs. However, if peritonitis de- large mares. However, by pulling the endome- velops, then signs become evident (typically over the trium gently caudally with the fingers, one usually first 24–48 h post-partum) and can include depres- can reach the majority of the uterus. sion, tachycardia, toxic mucous membranes, ileus, Small lacerations can close very quickly within a abdominal discomfort, and fever. few days of the injury. Therefore, if the transvag- inal examination is not performed immediately post- Clinical Hematology and Chemistry partum, it is possible that a previously existing laceration could no longer be identifiable. There- Immediately post-partum, there are no specific fore, if a mare has signs of peritonitis (particularly changes in clinical hematology or chemistry. Over after a dystocia), a uterine laceration should be sus- time, leukopenia or leukocytosis, hyperfibrinogen- pected, even if a specific laceration cannot be pal- emia, hemoconcentration, and azotemia may be seen pated. Be aware that one alternative cause for in association with peritonitis and dehydration. post-partum peritonitis is traumatized bowel (see Palpation and Ultrasonography per Rectum above). Interestingly, in some mares with uterine lacera- Abdominocentesis tions, we have noted apparently accelerated gross Immediately post-partum, abdominocentesis may uterine involution. On per rectum examination, show minimal changes. However, within 1–2 days the uterus often feels smaller than would be ex- of the injury, signs of peritonitis often are present. pected for the stage post-partum and can be highly Even with partial-thickness lacerations, some more j toned. mild abnormalities may be identified on abdomino- centesis. In cases of full-thickness lacerations, Palpation of the Reproductive Tract per Vagina signs of septic peritonitis typically are found. Many uterine lacerations sustained during parturi- tion occur in the uterine body, although lacerations Abdominal Ultrasonographic Examination also have been reported in the uterine horns.23–26 Immediately post-partum, no changes may be noted. Full-thickness lacerations represent the greatest Later, increased fluid, increased echogenicity of the threat. However, even partial-thickness lacera- abdominal fluid, and possibly fibrin tags may be tions can lead to bacterial contamination and sub- seen in association with peritonitis. sequent inflammation that may transfer into the abdominal cavity. Lacerations can occur either Miscellaneous ventrally or dorsally. If the laceration occurs in the In some cases in which a uterine laceration is uterine body, it is often within reach and therefore, strongly suspected but cannot be identified on pal- can be identified by palpation of the luminal uterine pation, exploratory celiotomy may be indicated to wall per vagina. If the laceration is very large, identify and close a potential laceration and to de- other abdominal organs (e.g., intestine and bladder) finitively identify the cause of developing peritonitis. may be present in the uterine lumen or at least Celiotomy or laparoscopy, in some cases, are the readily palpable through the tear. Because the en- only ways to differentiate between a uterine lacera- dometrial folds are very pronounced immediately tion and a gastrointestinal injury. There is one post-partum, it can sometimes be difficult to identify report in which dilute methylene blue was infused smaller or partial-thickness lacerations amidst the into a damaged uterus, and the diagnosis of a full- folds. thickness laceration was made laparoscopically If a laceration is suspected but none is identified when dye was visualized leaking into the on initial palpation per vagina, then transmural abdomen.26 palpation of the uterine wall should be performed. For this procedure, the veterinarian places a sterile Treatment arm into the uterus and a second arm into the rec- Both conservative medical treatment and aggressive tum. The dorsal uterine wall then is trapped be- surgical treatment of uterine lacerations have been tween the examiner’s hands. By applying gentle described.23–26 Based on these reports, there is no pressure and slowly “walking” across the dorsal sur- clear evidence to indicate that medical versus sur- face of the uterus, it becomes easier to flatten out the gical treatment is associated with a better or worse endometrial folds and identify small full-thickness outcome. In general, we make the decision on how and partial-thickness lacerations. Transmural pal- to treat the mare based on clinical signs, the size of pation of the uterine wall limits the depth to which the laceration, and the perceived potential for ab- the examiner’s arms can reach, and therefore, in the dominal contamination. For example, large lacer- immediately post-partum mare when the uterus is ations sustained during a complicated and quite large, it is useful only for the caudal portions of potentially contaminated delivery may warrant sur- the uterine body. Even with standard transvaginal gical repair, whereas smaller lacerations sustained

310 2007 ր Vol. 53 ր AAEP PROCEEDINGS IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE during delivery of a fresh foal may do well with only Evidence of significant ischemia or necrosis is asso- conservative therapy. Regardless of whether or not ciated with a poor prognosis for survival. Cases of surgery is performed, mares with uterine lacera- partial prolapse or intussusception of the tip of a tions should be treated with broad-spectrum sys- uterine horn may be more difficult to identify. In temic antimicrobials and anti-inflammatory drugs. these cases, persistent tenesmus, general restless- Fluid therapy and abdominal lavage often are indi- ness, colic, and tachycardia may be present. cated. Uterine lavage usually is not helpful; in cases of relatively large lacerations, uterine lavage Clinical Hematology and Chemistry is contraindicated, because most of the lavage fluid In the acute stages, there may be no significant will spill over into the abdomen, taking any contam- changes in blood work. If the condition goes un- inated uterine contents with it. If the mare devel- treated, hemoconcentration and azotemia may be ops septic peritonitis, then treatment for ileus and seen in association with dehydration. abdominal pain is necessary.1 Palpation and Ultrasonography per Rectum Prognosis for Systemic Recovery These procedures are not performed in cases of com- The prognosis for systemic recovery is variable and plete uterine prolapse, because they are not neces- depends largely on the degree of abdominal contam- sary and may induce additional straining. In cases ination that is sustained. As such, a better out- of partial prolapse, palpation and particularly ultra- come will be associated with early identification and sonography of the reproductive tract per rectum treatment of lacerations, whereas a poorer outcome may reveal the intussuscepted uterine horn. Ul- can be expected in cases where the laceration goes trasonographically, this may appear as telescoping undiagnosed for some time, thus resulting in exten- of concentric rings of soft tissue at the distal tip of a sive abdominal contamination. horn.

Prognosis for Future Reproductive Success Palpation of the Reproductive Tract per Vagina If the mare recovers systemically, the uterus typi- In cases of partial prolapse/intussusception, palpa- cally heals such that the laceration can no longer be tion per vagina is diagnostic, because the inverted identified. Although we do not have firm numbers piece of the reproductive tract can be palpated tele- on breeding success, it seems likely that most recov- scoping through the normal portions of the tract. ered mares will be of normal fertility and will be at In cases when the fetal membranes are also re- no increased risk of problems in subsequent tained, it is common to find the retained portion of foalings. The exception to this is mares that de- the membranes firmly attached to the area of the velop abdominal and uterine adhesions secondary to reproductive tract that is prolapsing. It is our in- peritonitis. We have infrequently seen mares with terpretation that this finding suggests that the severe adhesions manifest recurrent and significant weight of the membranes contributes to the abdominal pain. Additionally, in rare cases, uter- problem. ine adhesions can prevent normal uterine clearance and therefore, cause problems with fertility. Abdominocentesis 5. Uterine Horn Intussusception/Uterine Prolapse Abdominocentesis is often unremarkable unless a Uterine prolapse is uncommon in mares, but when it uterine laceration and associated peritonitis are occurs, it can be a life-threatening situation.27 present. An increase in RBCs may be found. Therefore, uterine prolapse should be treated as an emergency. Abdominal Ultrasonographic Examination This procedure typically is not performed unless Signalment/History peritonitis is suspected. Older, multiparous mares are at greatest risk, prob- ably because of repeated stretching and extreme Treatment relaxation of the reproductive tract during preg- Treatment centers around complete replacement of nancy and parturition. Intussusceptions and pro- the prolapse. Incomplete replacement will result lapses may be more common after prolonged in continued straining and reoccurrence of the pro- dystocia, because the uterus may be more atonic. lapse. Epidural anesthesia combined with IV anal- Additionally, the weight of retained fetal mem- gesia and sedation are strongly recommended before branes combined with prolonged straining to pass attempting to replace the prolapse. In our experi- the membranes act as predisposing factors.28 ence, epidural anesthesia is a key component to successful treatment, because it typically breaks the Physical Examination cycle of renewed straining/reprolapse and allows for In cases of complete uterine prolapse, the diagnosis some time for the uterus to involute. As soon as a is apparent on physical examination. The pro- prolapse is identified, any tissue protruding from lapsed organ should be examined carefully for lac- the vagina should be elevated to prevent develop- erations and for the overall condition of the tissue. ment of excessive dependant edema. One simple

AAEP PROCEEDINGS ր Vol. 53 ր 2007 311 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE method is to suspend the prolapsed tissue in a sheet Prognosis for Future Reproductive Success or sling that is supported by two assistants. Future fertility after prolapse depends largely on After appropriate analgesia has been supplied, the degree of damage sustained by the reproductive the prolapse should be palpated to determine if blad- tract. In cases in which replacement is rapid and der or portions of the gastrointestinal tract are complete, future fertility can be good.29 Zent28 re- present. A urinary catheter may be necessary to ported that the risk of future uterine prolapse may empty a prolapsed bladder before replacement. be increased in mares with a history of previous The uterus and perineum are then cleaned with prolapse. sterile saline. If lacerations are present, they should be sutured. If fetal membranes are re- 3. Post-Partum Problems in Systemically Healthy tained, gentle attempts can be made to manually Mares remove them. However, if resistance is felt, trac- The second broad group includes healthy post-par- tion should be immediately discontinued to avoid tum mares presenting for management. These further damage to the uterus. If they cannot be mares may require care after dystocia and/or Cesar- removed, membranes can be trimmed before re- ean section or treatment of retained fetal mem- placement of the uterus to reduce the weight of the branes to avoid later development of problems. membranes and the associated tension on the Poor milk production and urovagina are other exam- uterus. The uterus can then be replaced using the ples of problems that can occur post-partum that do flat of the hand beginning with the caudal most not affect the systemic wellbeing of the mare. Com- portions of the prolapse and proceeding to the most mon treatment options will be reviewed, and prog- anterior portions. Care should be taken to insure nosis for recovery and future reproductive success that the uterine horns are completely everted, be- will be discussed. cause even small remaining intussusceptions of the tips of the uterine horns will result in renewed 1. Retained Fetal Membranes straining and reprolapse after the anesthesia is In the mare, the fetal membranes are defined as gone. We have found that the rounded end of a retained if they are not passed in their entirety sterile mare vaginal speculum works very well as an within3hofthecompletion of second-stage labor. extension to the arm to insure complete replacement The incidence of retained fetal membranes (RFM) in 30–32 of even the tips of the uterine horns. the mare can be as high as 10%. Complica- When replacement is complete, oxytocin should be tions arising from RFM include metritis, laminitis, administered to increase uterine tone and help pre- and endotoxemia. These secondary problems can vent reprolapse. Oxytocin should not be adminis- be life threatening and thus, significantly decrease tered before replacement, because it may cause the the prognosis for systemic recovery. The goal, therefore, is to identify RFM early and begin ther- uterus to become less malleable and therefore, more apy to both encourage passage of the membranes difficult to replace. Broad spectrum antibiotics and and prevent the development of secondary non-steroidal anti-inflammatory drugs typically are complications. administered, and supportive therapy, including IV The pathogenesis of RFM is multifactorial. In fluid administration, is indicated. Uterine lavage cattle, enzymatic breakdown of collagen and other may be performed after replacement as long as it proteins is necessary for the membranes to pass does not cause renewed straining on the part of the efficiently. Lack of this “collagenolysis” is probably mare. Large-volume (3–15 l) saline lavage can one underlying cause of RFM.33 This breakdown in serve two purposes. First, it will aid in evacuation collagen likely occurs gradually over the last several of contaminants, and second, it will help expand the weeks of gestation and depends on the progression uterus and insure that all parts of the uterus are of hormonal changes that occur before normal par- returned to their proper positions. turition. Thus, any process that interferes with the normal physiology of the pre-partum period in the cow Prognosis for Systemic Recovery can increase the risk of RFM. In addition, the cessa- tion of blood flow through the placenta that occurs Complete prolapse of the uterus should be treated as when the umbilical cord breaks may lead to collapse of an emergency, because continued prolapse can lead the fetal vessels and a corresponding decrease in size to permanent damage to the uterus and potentially, of the chorionic microvilli.34 Therefore, any process to rupture of the uterine vessels. Rupture of the that causes swelling of the microvilli or endometrium uterine vessels can result in hemorrhagic shock and will adversely affect membrane passage. Although 2 sudden death. Ischemia and necrosis of the uterus placentation is different in the mare, it is likely that is associated with a poor prognosis. However, if the similar processes are involved in the pathophysiology prolapse is successfully replaced and no secondary of fetal-membrane retention in this species. There- complications develop (septic metritis, peritonitis, or fore, abortion, induction of parturition, Cesarean sec- hemorrhage), then the prognosis for recovery is tion (particularly if it is performed before the mare good. enters first-stage labor), twin pregnancy (which can

312 2007 ր Vol. 53 ր AAEP PROCEEDINGS IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE result in abnormal pre-partum physiology), dystocia, in identifying partially retained membranes. In contamination of the uterus at parturition, placentitis some cases of partial retention, only small portions of (which can cause inflammation of the microvilli and the membranes remain attached. These pieces may microcotyledons), and other miscellaneous pathologies not be large enough to be seen protruding from the such as hydropic conditions can increase the risk of vulva. Thus, a diagnosis of RFM could be missed. RFM in the mare. In cases in which there is no definitive evidence that the placenta has been passed in its entirety, palpation Signalment/History and ultrasonographic examination of the uterus can RFM can occur in any breed and at any age, but it is lead the clinician to suspect partial membrane reten- more common in draft breeds than in light-horse tion. Palpation of the reproductive tract typically re- breeds and more common in mares Ն 15 yr of veals a poorly involuted uterus. As the disease age.32,35 Friesien mares are at significantly in- progresses, there is often a build up of intrauterine creased risk, even after an uncomplicated delivery. fluid, although this may not be present in the earlier In one study, 54% of Friesian mares retained their stages. Ultrasonographically, retained membranes fetal membranes after normal foalings.36 Friesians appear as distinctive hyperechoic areas within the lu- foaling at 5–17 yr of age had the highest incidence of men of the uterus. RFM. Interestingly, mares of this breed also are Palpation of the reproductive tract per vagina can unusually tolerant of the retained membranes and also be helpful in arriving at a diagnosis. It often is typically do not develop any of the severe secondary possible to palpate partially retained membranes by complications, even without treatment.37 this route. The character of the uterine contents can be assessed (appearance and odor) to help give Physical Examination the veterinarian some idea of the state of the intra- If the membranes have not passed within3hof uterine environment. delivery of the foal and if the membranes are re- tained in their entirety, then a diagnosis of RFM is Treatment apparent on physical examination. However, in Administration of oxytocin can effectively cause pas- some cases, the fetal membranes may be torn, and sage of retained fetal membranes. We recommend only small parts of the membranes may be retained. beginning oxytocin therapy as soon as a diagnosis is In these cases, the diagnosis may not be apparent on made (i.e., 3 h after delivery of the foal if the mem- routine physical examination, because the small re- branes have not yet passed). Sometimes, a single tained pieces may not be large enough to protrude injection of 10–20 IU, IV can result in membrane from the vulva. passage within minutes. However, many times the If a diagnosis of RFM is made, treatment should results are not as dramatic. If an initial dose of be initiated, and the mare must be monitored care- oxytocin proves ineffective, we place affected mares fully for any signs of complications including metri- on a regular treatment regimen of oxytocin. Dose tis, laminitis, and endotoxemia. Physical and frequency of administration are highly variable examination of the fetal membranes themselves is and depend largely on clinician preference. If the necessary to be certain that the membranes have mare begins to show signs of discomfort in associa- completely passed, and often, it is helpful in identi- tion with uterine contractions, then the dose and/or fying a potential cause for cases of membrane reten- frequency is reduced. The following are typical tion. Therefore, after they have passed, the schedules used at our hospital. membranes should be examined grossly and if they are still in good condition, possibly histologically to ● 10–20 IU, IV or IM every 15 min for one 2-h (1) confirm full passage of the membranes and (2) try block in the morning and one 2-h block in the and identify potential underlying causes for reten- evening. tion such as placentitis. The most common site of ● 10–20 IU, IV or IM every 1 h around the clock. partial fetal membrane retention is the tip of the ● Continuous oxytocin infusion through IV cath- non-pregnant horn. Therefore, lacerations or holes eter. Dose varies depending on mare comfort in this portion of the placenta should raise a warn- level but typically starts at a dose of 1 IU/min ing flag for potential partial membrane retention. in an appropriate crystalloid solution. It is recommended that the veterinarian specifically identify the avillous area at the tip of each uterine Carbetocin,k a long-acting oxytotic product, is avail- horn that overlaid the oviduct papilla, because this able in the United Kingdom and Canada. This portion of the placenta represents the distal most tip drug reportedly results in prolonged uterine con- of each uterine horn. tractions, and therefore, it allows for reduced fre- quency of dosing. However, to the author’s Other Diagnostics knowledge, it is not available in the United States, Early on in the progress of RFM, well before any sec- and no controlled studies have been published on its ondary problems develop, there are a few additional effects on treatment of RFM in the mare. In some diagnostic tests that are required. Palpation and ul- refractory cases, prostaglandin (250 ␮g cloprostenoll trasonography of the reproductive tract may be helpful or 10 mg dinoprost tromethaminem) may be admin-

AAEP PROCEEDINGS ր Vol. 53 ր 2007 313 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE istered, because it has longer uterotonic effects than trum antibiotic treatment (e.g., potassium penicillin does oxytocin. and gentamicin) as well as non-steroidal anti-in- It is my experience that if oxytocin does not cause flammatory drugs (e.g., flunixin meglumine) are be- passage of the membranes within ϳ12 h, then it is gun in an attempt to prevent secondary common for the membranes to be retained for days complications. Mares are carefully monitored for until they necrose and fall away from the endome- signs of endotoxemia and laminitis, and additional trium. Nonetheless, regular oxytocin treatment treatments may be added if adverse signs develop should be continued, because it will maintain uter- over time. ine tone and favor expulsion of debris and fluid. More recently, intraumbilical infusion of collage- Prognosis for Systemic Recovery nase has been reported as a treatment for RFM.38 In uncomplicated cases of RFM in which the mem- Two hundred thousand units of bacterial collage- branes are eventually passed without development nase dissolved in1lofsterile saline were infused of secondary complications, the prognosis for sur- into the umbilical-cord vessels of RFMs. In treated vival of the mare is excellent. If secondary compli- mares, the retained membranes were passed within cations arise, the prognosis is reduced 6 h of treatment with no reported side effects. This proportionately. In the worst cases of septic metri- treatment is based on earlier work in cows in which tis and laminitis, death can occur. bacterial collagenase was shown to effectively hy- drolyze the collagen links between the membranes Prognosis for Future Reproductive Success and the endometrium.39 It should be noted that If the mare survives and does not develop secondary the single study in mares examined a very small problems, her prognosis for future fertility is good. number of animals with RFM (n ϭ 4) and included Depending on the length of time of retention and the no untreated controls. This treatment is likely to development of secondary complications, for most be difficult to administer in cases of chronically re- breeds, we recommend that affected mares not be tained, partially necrotic fetal membranes. Addi- bred on foal heat. The mare’s uterus should be tionally, in cases in which the membranes are examined during her first post-partum diestrus, and partially autolyzed, it seems unlikely that injection if everything looks good at that time, she can be bred into the umbilical vessels would result in effective on her subsequent estrus. However, keep in mind perfuse of the chorioallantois. In fact, this problem that it has been reported that there is no difference was encountered in one of the four mares in the 1998 in conception rates after the first breeding than at study.38 the end of the breeding season in mares that have or Although it is contraindicated to forcibly extract have not retained fetal membranes, regardless of retained membranes, it is reasonable to attempt to the length of time of retention.32 Friesian mares encourage passage of the membranes by applying are particularly resilient. In this breed, it has been gentle pressure. If resistance is met, this should be reported that reproductive performance (defined as discontinued immediately before damage is done to pregnancy rate, foaling, and foal-heat breeding) did the endometrium. not differ between Friesian mares that did or did not Uterine lavage may be helpful at evacuating de- retain their fetal membranes. Nor did it differ in bris from the uterus. In cases of full retention, Friesian mares from whom the retained membranes keep in mind that the lavage is acting on the allan- were or were not extracted manually.37 Therefore, toic side of the fetal membranes and not on the in Friesians at least, RFM and manual removal of endometrium itself. However, if one fills the uterus the fetal membranes are not valid reasons to avoid with large volumes of saline, this will result in uter- foal-heat breeding. ine distention and potentially, endogenous oxytocin release that may further aid in membrane passage. 2. Management of Mares After Cesarean Section If the membranes are partially separated from the Cesarean section in the mare most commonly is endometrium, then the lavage may be effective at limited to the referral hospital setting. Proper clearing necrotic debris from the endometrial sur- management of the post-Cesarean section mare is face and therefore, may decrease the risk of second- important for the mare’s survival and future repro- ary metritis. We typically perform uterine lavage ductive success. Additionally, practitioners should one time daily when membranes are retained. be aware of the prognosis for mares and foals after In cases of chronic retention, we may tie small the Cesarean section so that they will be better able weights (e.g., 250-ml bottles of saline) to the re- to advise mare owners facing the possibility of refer- tained membranes. It is our hope that this weight ral of a mare for possible surgery. will provide a steady but gentle increased traction on the membranes that will encourage passage. History Heavy weight is to be avoided, because it is more Cesarean section most often is performed to deliver likely to cause the membranes to lacerate or damage a foal when delivery per vagina proves to be impos- the endometrium. sible or is too risky for the mare. Thus, many If the membranes still are not passed 6 h after the mares presenting for care after Cesarean section completion of second-stage labor, then broad-spec- have a history of severe dystocia. Elective Cesare-

314 2007 ր Vol. 53 ր AAEP PROCEEDINGS IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE ans also may be performed in cases where vaginal sarean section may be preferable to CVD if dystocia delivery is considered dangerous for the mare (e.g., is protracted and CVD is likely to be difficult and body-wall rupture or pelvic fractures with reduced prolonged. In contrast, a second study identified no pelvic diameter), in mares with a history of recur- difference in outcome between mares undergoing rent dystocias, or concurrently with colic Cesarean section versus CVD. Byron et al.43 rec- surgery.40,41 ommended selection of the delivery method that is likely to result in the fastest delivery of the foal. Management Management of mares after Cesarean section in- Prognosis for Future Reproductive Success of the cludes routine post-celiotomy care (e.g., fluid ther- Mare apy, systemic antibiotics, non-steroidal anti- There is a misconception that a mare’s future repro- inflammatories, incisional care, monitoring of ductive success is adversely affected by Cesarean patient comfort, and overall physical condition, etc.). section. In contrast, using modern surgical meth- Specific care of the reproductive tract is also insti- ods and anesthesia, several reports indicate that the tuted. Because Cesarean section is associated with prognosis for future fertility in post-Cesarean sec- a higher incidence of RFM, most mares are begun on tion mares is very good. In one report, all mares a course of oxytocin treatment immediately after bred back in the year after elective Cesarean section surgery or even during surgery. This is intended to became pregnant.40 In other studies involving minimize the risk of RFM and also to encourage mares presenting for largely emergency Cesarean uterine involution. sections, the pregnancy rate in the year after sur- There is considerable variation among clinicians gery ranged from 50% to 72%.42,43 Notably, in one as to whether or not uterine lavage is performed study, pregnancy rates in mares bred the same year after Cesarean section.41,42 Some elect for daily as the Cesarean section were 60%.43 Thus, mares uterine lavage in an attempt to keep the uterus free most often are able to return to a successful breeding of unwanted debris and fluid accumulation. Others career after Cesarean section; in some cases, they avoid post-operative lavage for fear of leakage into can even return to successful breeding within the the abdomen or fear of irritation to the recently same breeding season. In general, we make deci- closed incision site. To the author’s knowledge, sions on future breeding management on a case-by- there have been no reports designed specifically to case basis. For example, mares undergoing study the efficacy of uterine lavage at improving Cesarean section early in the season and who expe- post-operative fertility. We typically monitor post- rience minimal post-operative complications may be Cesarean section mares by daily palpation and ul- returned to breeding later that same year, whereas trasonography per rectum beginning 24–48 h after mares undergoing surgery later in the year and who Cesarean section. If significant amounts of un- experience significant complications may be best wanted uterine fluid accumulate or if the character waiting until the next year before breeding. of the lochia becomes malodorous, then uterine la- vage may be performed. If the uterus seems to be Prognosis for Survival of the Foal involuting well, then we often choose not to perform The prognosis for survival of foals delivered by Ce- uterine lavage and instead manage the mare with sarean section depends very largely on the duration oxytocin as needed (see section on RFM for doses of second-stage labor.43,44 Unfortunately, in most and dosing intervals). cases, the decision to proceed to a Cesarean section is made only after many hours of attempting a vag- Prognosis for Systemic Recovery of the Mare inal delivery, thus greatly reducing the chances of The prognosis for systemic recovery in mares under- delivering a live foal with minimal complications. going Cesarean section has improved dramatically Delivery of a live foal after Cesarean section varies over the last few decades and now is very good. from 11% to 42%, and survival of the foal to dis- Overall survival rates in mares undergoing elective charge from the hospital is lower (5–31%).41–43 or emergency Cesarean section without concurrent As might be expected, survival of foals delivered by colic surgery is ϳ90% with a 100% survival rate appropriately timed elective Cesarean section was reported in a small group of mares undergoing ex- much higher (seven of eight foals survived to dis- clusively elective Cesareans.40–43 Lower survival charge in one study).40 The wide range in foal sur- rates (38%) can be expected in mares undergoing vival consistently depends on the duration of second- Cesarean section concurrently with colic surgery. stage labor.43 Thus, whether or not a mare has a In these cases, the poor outcome is more likely Cesarean section is not what determines outcome caused by problems associated with the gastrointes- for the foal. Rather, it is how long it takes for a foal tinal tract than problems with the Cesarean section to be delivered, regardless of delivery method, that itself. is the critical factor. Therefore, refer early. In one study, mares undergoing Cesarean section had a lower incidence of complications than those 3. Management of Mares After Dystocia undergoing controlled vaginal delivery Many aspects of management of mares after Cesar- (CVD). Thus, Freeman et al.41 suggested that Ce- ean section also apply to the post-dystocia mare.

AAEP PROCEEDINGS ր Vol. 53 ր 2007 315 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE Because many dystocias are managed on the farm, dure is, at worst, innocuous, and in many cases, it this work often falls on the general practitioner. greatly aids uterine clearance and speeds involution. History We do not routinely perform abdominocentesis on Mares of any age and breed can experience dysto- mares after correction of a dystocia. Abdominocen- cias. Recurrent dystocia occurring in separate tesis becomes important in cases in which signifi- years in the same mare is uncommon (6 of 247 cant uterine damage is suspected. It has been dystocia cases in one report).43 Mares with a his- reported that elevation of a single peritoneal fluid tory of reduced pelvic diameter (e.g., secondary to a value (nucleated cell count, total protein, or percent- pelvic fracture or mass) may be at increased risk. age of neutrophils) in post-partum mares may be incidental. However, increases in two or more of Management these values is likely to be clinically significant.46 Management of the dystocia itself is beyond the scope of this manuscript. However, it is worth not- Prognosis for Systemic Recovery of the Mare ing that a recent report describes severe complica- The prognosis for systemic recovery in mares after tions after contamination of the abdominal cavity resolution of a dystocia by assisted vaginal delivery with even small amounts of a commonly used poly- (AVD) or CVD is excellent (ϳ90%).43,44 One study ethylene-polymer obstetrical lubricant (PEP, 45 suggested that CVD may be associated with more J-Lube). Contamination of the peritoneal cavity complications and a poorer outcome (only a 71% with as little as the equivalent of1lofa1%(w/v) survival rate in mares undergoing CVD).41 This solution of J-Lube can result in toxic, suppurative may be a result of the more prolonged deliveries in peritonitis and often death within minutes of the CVD mares in the 1999 study rather than a primary contamination. Therefore, it may be prudent to effect of the CVD itself. If a fetotomy is necessary avoid the use of J-Lube in cases in which a uterine to resolve the dystocia, then survival is lower (56%). laceration is present, in which there is a high risk of Byron et al.43reported that this may have been at- damage to the uterus during mutations, or when tributable to the economic necessity of performing Cesarean section is likely. fetotomy in some mares that would have been better After correction of a dystocia and vaginal delivery served by Cesarean section. Alternatively, poorer of the foal, the mare will be at increased risk for outcomes in mares undergoing fetotomy may be RFMs. As such, we typically begin all affected caused by the fact that fetotomy is frequently used mares on oxytocin treatment after the foal is deliv- only as a “last resort” after prolonged attempts at ered and continue the treatment until the mem- manipulations of the foal.29 These mares, there- branes pass or until the mares becomes fore, will be at increased risk for damage to the uncomfortable as a result of the uterine contractions reproductive tract; this is not a result of the feto- (see section on RFM for doses and dosing schedules). tomy itself but rather a result of the prolonged du- The reproductive tract should be examined per ration of the entire process. vagina in an attempt to identify any significant damage to the tract sustained during the delivery. Prognosis for Future Reproductive Success of the Usually, the uterus is too large to permit full eval- Mare uation of the uterine horns per vagina. However, it is recommended that an attempt be made to exam- Overall pregnancy rates are good after resolution of ine as much as is feasible, because dystocia will a dystocia using either AVD or CVD. If mares were increase the risk of uterine and vaginal lacerations. bred in the same season as the dystocia, pregnancy rates were lower than long-term pregnancy rates Early identification of these problems is critical to a 43 successful outcome (see above). (58% vs. 66%, respectively). The author is aware Contamination of the uterus is inevitable after of no studies that report fertility after appropriate vaginal manipulations of the foal. Contamination use of fetotomy. It seems likely that fertility after can vary from minimal to severe. This contamina- fetotomy will vary largely depending on the degree tion combined with the common complication of of damage sustained by the reproductive tract after RFM leads me to perform uterine lavage regularly initial attempts at mutation and subsequent feto- on most mares after dystocia. In general, an initial tomy and also based on the experience of the indi- lavage is performed either after delivery of the foal vidual performing the fetotomy. or the next day. Daily examinations of the repro- ductive tract by palpation and ultrasonography per Prognosis for Survival of the Foal rectum are then performed to monitor uterine invo- The duration of second-stage labor is the single most lution. If significant fluid or debris is identified in important determinant of the outcome of the foal. the lumen, then daily lavages with sterile saline are It has been reported that for every 10-min increase performed until the uterus appears clear. No con- in stage II labor beyond 30 min, there is a 10% trolled studies have been performed to show that increased risk of the foal being dead at delivery and post-dystocia uterine lavage results in improved re- a 16% increased risk of the foal not surviving to covery. However, it is my opinion that the proce- discharge.44 In foals surviving to discharge, the

316 2007 ր Vol. 53 ր AAEP PROCEEDINGS IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE length of stage II was 44–71 min. For non-surviv- ● Days 1–7: 150 mg progesterone and 50 mg ing foals, the length was 85–249 min.43,44 estradiol 17␤,IM. The length of time spent on attempting vaginal ● Day 7: 5 mg prostaglandin, IM. correction of a dystocia on the farm is only one ● Days 1–10: 500 mg sulpiride, q 12 h, IM. component of the length of second-stage labor. In mares referred to secondary care facilities for Place the foal on the mare beginning on day 1 of dystocia resolution, travel distance, travel time, treatment to supply suckle stimulation. The foal time spent arranging for transport, loading the will initially require supplementation. The foal mare, etc. all will play a role.44 The best outcome must be an aggressive suckler for this to work. for the foal was reported in those mares that spent If not, the mare can be milked manually five times a minimal time on the farm in second-stage labor be- day until milk production is sufficient for the foal. fore being referred to a local (10-min average travel Oxytocin may be administered discretionarily at 5 time) referral institution for rapid delivery of the IU, IV, or IM to enhance milk let down. foal.43 By day 10, 80% of treated mares will lactate suf- ficiently to support a foal. 4. Hypogalactia/Agalactia An oral formulation of sulpiride is reportedly in Poor milk production in a post-partum mare is an development and may be available soon. The oral uncommon but significant problem for the wellbeing formulation will be easier to administer and also of the foal. Although hand feeding of an under- will be substantially less expensive than the inject- nourished foal is an option, this is a time-consuming able form. and difficult undertaking. Therefore, development of methods to stimulate milk production in poor 5. Urovagina/Urometra producing mares is desirable. Urovagina (vesicovaginal reflux) is the retention of incompletely voided urine in the cranial vaginal for- Poor Nutrition nix.52 If this condition is severe and/or if the mare’s cervix is open, urine may gain access to the uterus, A common and often overlooked reason for poor milk resulting in urometra and a secondary endometritis. production is poor nutrition. The nutritional de- This condition is most often seen in older, multipa- mands of the lactating mare are significantly rous mares and can occur after both normal deliver- greater than those of even late pregnant mares. ies and dystocias. Stretching and relaxation of the Some mare owners are simply unaware of the in- caudal reproductive tract occurs during vaginal de- creased metabolic needs of mares nursing foals. livery and leads to urine pooling. Pre-existing poor Simple improvements in nutrition sometimes are all perineal conformation also may contribute to the that is needed to stimulate milk production. Re- condition. stricted water intake, selenium deficiency, and Urovagina and urometra are associated with re- stress also have been implicated as causes for hy- duced fertility because of the resulting secondary en- pogalactia in mares.47 dometritis, vaginitis, and cervicitis.53 Additionally, Fescue Toxicosis the accumulation of urine in the vagina and uterus leads to changes in pH that can adversely affect One of the hallmarks of fescue toxicosis is poor spermatozoa. milk production. The effects of endophyte-in- fected fescue on lactating mares have been well Clinical Signs and Diagnosis described and involve suppression of prolactin re- In cases of severe urovagina and urometra, the mare lease by an ergot alkaloid toxin produced by the may intermittently discharge urine from her vulva. 48,49 endophyte. Prolactin levels will return to This can lead to urine scalding of the perineum and normal if the mare is removed from the source of inner thighs. In more mild cases, outward signs the toxin for 2–3 wk. Because dopamine sup- may not be evident. However, echogenic fluid presses prolactin release, the use of dopamine an- (urine) may be apparent on transrectal ultrasono- tagonists are central to treatment of agalactia graphic examination of the vagina and uterus. associated with fescue toxicosis. Domperidone If urovagina is suspected, a definitive diagnosis can (1.1 mg/kg, PO q 24 h) or sulpiride (1 mg/kg, IM q be made based on vaginal speculum examination 12–24 h) is commonly used for this purpose. and visualization of urine in the anterior vagina. Miscellaneous Comments Treatment Recently, hormonal induction of lactation in non- Many older mares will pool urine in the post-partum foaling mares has been reported.50 The originally period, but it is important to recognize that most will reported protocol has been refined and simplified correct after they come under the influence of pro- over the past several years, and it has now devel- gesterone after their foal-heat ovulation. There- oped into a practical and simple method for reliably fore, if a diagnosis of urovagina/urometra is made in inducing lactation in non-foaling mares.51 The a post-partum mare, the decision as to whether or technique involves not surgery is indicated should be delayed until after

AAEP PROCEEDINGS ր Vol. 53 ր 2007 317 IN-DEPTH: PERINATOLOGY—END OF PREGNANCY THROUGH BEGINNING OF LIFE foal heat. Ideally, affected mares should then be References and Footnotes examined during their 20 day heat, because the 1. Dolente BA. Critical peripartum disease in the mare. incidence of urine pooling is highest during estrus. Vet Clin North Am [Equine Pract] 2004;20:151–165. 2. Sertich PL. Periparturient emergencies. Vet Clin North If urovagina persists even after the mare has been Am [Equine Pract] 1994;10:19–36. through a post-partum diestrous period, surgical 3. Blanchard TL, Scrutchfield WL, Taylor TS, et al. Manage- correction of urovagina may be indicated. This pro- ment of dystocia in mares; retained placenta, metritis, and cedure has been described elsewhere.54 laminitis. Compend Cont Educ Pract Vet 1990;12:563–569. 4. Blanchard TL, Vaala WE, Straughn AJ, et al. Septic/toxic Whether or not a mare corrects after her foal heat, metritis and laminitis in a postparturient mare. Equine Vet conservative management of urovagina is advised Sci 1987;7:32–34. during the early post-partum period, because many 5. Lofstedt R. Haemorrhage associated with pregnancy and mares develop secondary urometra that can delay parturition. Equine Vet Edu 1994;6:138–141. 6. Rooney JR. Internal hemorrhage related to gestation in the uterine involution. In our experience, mares with mare. Cornell Vet 1964;54:11–17. post-partum urovagina can pool very large volumes 7. Pascoe RR. Rupture of the utero-ovarian or middle uterine of fluid in the uterus. In our clinic, post-partum artery in the mare at or near parturition. Vet Rec 1979;104: mares that accumulate significant amounts of uter- 77. 8. Rooney JR, Stowe L. Effects of age and impending parturi- ine fluid are treated with daily large-volume uterine tion upon serum copper of Thoroughbred mares. J Nutr lavages. These lavages can be both therapeutic 1968;95:179–183. and diagnostic, because the character of the effluent 9. Curtis MT, Lefer AM. Protective actions of naloxone in hem- can aid in the diagnosis of urometra. orrhagic shock. Am J Physiol 1980;239:H416–H421. 10. Curtis MT, Lefer AM. Actions of opiate antagonists with In severely affected post-partum mares, urine re- selective receptor interactions in hemorrhagic shock. Circ accumulates quickly in the vagina and uterus. Shock 1983;10:131–145. Although daily lavages may result in evacuation of 11. Doyle AJ, Freeman DE, Rapp H, et al. Life-threatening the uterine contents, the fluid typically reaccumu- hemorrhage from enterotomies and anastomoses in 7 horses. Vet Surg 2003;32:553–558. lates quickly such that the uterus is again distended 12. Frees KE, Gaughan EM, Lillich JD, et al. Severe complica- with urine within 24 h of lavage. These mares are tion after administration of formalin for treatment of progres- maintained on daily, large-volume saline lavage and sive ethmoidal hematoma in a horse. J Am Vet Med Assoc regular oxytocin injections until resolution of the 2001;219:950–952. 13. Taylor EL, Sellon DC, Wardrop KJ, et al. Effects of intra- problem. Lavage is continued until the effluent re- venous administration of formaldehyde on platelet and coag- covered is clear. This may require as much as 15 or ulation variables in healthy horses. Am J Vet Res 2000;61: more l of saline. Exercise also is likely to be bene- 1191–1196. ficial, because it may aid in mechanical evacuation 14. Trumble TN, Ingle-Fehr J, Hendrickson DA. Laparoscopic intra-abdominal ligation of the testicular artery following of uterine fluid. A Caslicks procedure may help castration in a horse. J Am Vet Med Assoc 2000;216:1596– some mares, because pneumovagina can predispose 1598. the mare to urovagina.55 15. Lofstedt R. Miscellaneous diseases of pregnancy and partu- Simple nursing care may be indicated if urine rition. In: McKinnon AO, Voss JL, eds. Equine reproduc- tion. Philadelphia: Lea & Febiger, 1993;596–603. scalding of the skin is seen. This includes regular 16. Platt H. Caecal rupture in parturient mares. J Comp washing of the affected areas to remove residual Pathol 1983;93:343–346. urine and application of protective ointments such 17. Dart AJ, Pascoe JR, Snyder JR. Mesenteric tears of the as zinc oxide to protect the skin. Additionally, poor descending (small) colon as a postpartum complication in two mares. J Am Vet Med Assoc 1991;199:1612–1615. body condition can predispose to urine pooling be- 18. Ragle CA, Southwood LL, Galuppo LD, et al. Laparoscopic cause of a loss of pelvic fat and a secondary sunken diagnosis of ischemic necrosis of the descending colon after perineum.56 Thus, weight gain often is beneficial. rectal prolapse and rupture of the mesocolon in two postpar- tum mares. J Am Vet Med Assoc 1997;210:1646–1648. 19. Zamos DT, Ford TS, Cohen ND, et al. Segmental ischemic Prognosis for Future Reproductive Success of the necrosis of the small intestine in two postparturient mares. Mare J Am Vet Med Assoc 1993;202:101–103. 20. Livesey MA, Keller SD. Segmental ischemic necrosis follow- If the condition of urovagina/urometra resolves or ing mesocolic rupture in postparturient mares. J Am Vet can be corrected surgically, the prognosis for future Med Assoc 1986;10:763–768. fertility of the mare is often good. Because this 21. Steel CM, Gibson KT. Colic in the pregnant and peripartu- condition is most common in older mares, a complete rient mare. Equine Vet Edu 2001;13:122–135. 22. Dascanio JJ, Ball BA, Hendrickson DA. Uterine tear with- breeding soundness examination, including endo- out a corresponding placental lesion in a mare. J Am Vet metrial swab for culture and endometrial biopsy, is Med Assoc 1993;202:419–420. typically indicated to better assess the mare’s poten- 23. Patel J, Lofstedt RM. Uterine rupture in a mare. JAmVet tial fertility and to ascertain the extent of any sec- Med Assoc 1986;889:806–807. 24. Brooks DE, McCoy DJ, Martin GS. Uterine rupture as a ondary problems (e.g., bacterial endometritis) that postpartum complication in two mares. J Am Vet Med Assoc may have resulted from the urovagina. 1985;187:1377–1379. Mares that have developed urovagina/urometra 25. Fischer AT, Phillips TN. Surgical repair of a ruptured subsequent to foaling are at increased risk for de- uterus in five mares. Equine Vet J 1986;18:153–155. 26. Hassel DM, Ragle CA. Laparoscopic diagnosis and conser- veloping the condition after future foalings. Often, vative treatment of uterine tear in a mare. J Am Vet Med the problem worsens with each foal. Assoc 1994;205:1531–1536.

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