Arthroscopic anatomy of the equine temporomandibular joint.

OBJECTIVE: To develop an arthroscopic approach to, and describe the arthroscopic anatomy of, the equine temporomandibular joint (TMJ). STUDY DESIGN: Cadaveric study, after which the technique was tested in horses. ANIMALS OR SAMPLE POPULATION: Ten cadaveric equine heads and 5 normal horses (age, 5-13 years; weight, 425-545 kg). METHODS: Specimens or horses were positioned in right lateral recumbency. After fluid distention of the TMJ, arthroscopic portals were made in the dorsal compartment over the most prominent portion of the joint outpouching (caudodorsal approach) and in rostral and intermediate locations. The joint was explored and photographed. Positional changes in the mandible were made to determine if observation of the joint could be improved. Instrument portals were created to assess the feasibility of surgical arthroscopy. Cadaveric heads were dissected to assess iatrogenic damage, whereas experimental horses were observed for postoperative complications for 30 days. RESULTS: A caudodorsal arthroscopic approach provided the best evaluation of the dorsal compartment of the TMJ. The approach allowed observation of the rostral and caudal synovial pouches and the lateral aspect of the joint including the articular disc. Examination of the medial aspect of the joint was limited to the most rostral and caudal aspects. Access to the lateral aspect of the ventral compartment of the TMJ was precluded by the position of the transverse facial artery and vein. In specimens, iatrogenic damage was minimal and limited to the articular fibrocartilage, articular disc, and penetration of the parotid salivary gland. If the latter also occurred in horses, no adverse effects were noted. In horses, mild fluid extravasation occurred and resolved within 1 day. All horses ate normally after surgery but had periarticular swelling and mild pain upon palpation of the TMJ for 2 days. CONCLUSIONS: A caudodorsal arthroscopic approach to the TMJ allowed adequate observation of the lateral aspect of the dorsal compartment of the joint. Access to the ventral compartment was precluded by the location of the transverse facial artery and vein. CLINICAL RELEVANCE: Conditions affecting the lateral and caudal aspects of the dorsal compartment of the TMJ should be visible by arthroscopy.

Failure of holmium:yttrium-aluminum-garnet laser lithotripsy in two horses with calculi in the urinary bladder.

Holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy was attempted in a mare and a gelding with calculi in the urinary bladder. The procedure was unsuccessful in producing adequate fragmentation of the calculi. In the gelding, pulsed dye laser lithotripsy was subsequently used to fragment the urolith. Manual removal of the urolith via the urethra was performed in the mare.

Comparison of equine amnion and a nonadherent wound dressing material for bandaging pinch-grafted wounds in ponies.

OBJECTIVE: To evaluate healing of pinch-grafted wounds on the distal aspect of the limbs of ponies bandaged with equine amnion or a standard nonadherent wound dressing material. ANIMALS: 6 ponies. PROCEDURE: A 2.5x2.5-cm full-thickness section of skin was removed from the dorsal aspect of each limb at the midpoint of the metacarpus or metatarsus. Six days later, wounds were grafted with partial-thickness pinch grafts. Half the wounds were bandaged with amnion, and the other half were bandaged with a nonadherent dressing. Bandages were changed every 3 days until wound healing was complete. At each bandage change, numbers of grafts lost were recorded, and wounds were measured. RESULTS: Percentage of grafts lost from wounds bandaged with amnion was not significantly different from percentage lost from wounds bandaged with the nonadherent dressing. Median healing time for wounds bandaged with amnion (30 days) was significantly less than median healing time for wounds bandaged with the nonadherent dressing (39 days). All wounds were healed by day 45. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that amnion can be used for bandaging pinch-grafted wounds on the distal aspect of the limbs of ponies.

Determination of the lactate breakpoint during incremental exercise in horses adapted to dietary corn oil.

OBJECTIVE: To determine lactate breakpoint of horses and test for effects of training and dietary supplementation with corn oil on that breakpoint. ANIMALS: 7 healthy Arabian horses. PROCEDURES: Horses received a control diet (n = 4) or a diet supplemented with 10% corn oil (4). A training program, which comprised two 5-week conditioning periods with 1 week of rest, was initiated. Submaximal incremental exercise tests (IET) were conducted before the first and after both conditioning periods. Blood samples for determination of blood lactate and plasma glucose concentrations were collected 1 minute before IET and during the 15 seconds immediately preceding each speed change. Data collected were fit to one- and two-slope broken-line models and an exponential model. RESULTS: Good fits were obtained by application of the broken-line models (adjusted R2 > 0.92) to blood lactate concentration versus speed curves. Lactate breakpoints increased 41% after training. After training, slope 2 and peak blood lactate concentrations were greater in the corn oil group, compared with controls. Mean blood lactate concentration at the breakpoint was not affected by training or diet. Plasma glucose concentration versus speed curves also fit the broken-line models, and glucose breakpoints preceded lactate breakpoints by approximately 1 m/s in the second and third IET. CONCLUSIONS AND CLINICAL RELEVANCE: Lactate breakpoints can be determined for horses, using blood lactate concentration versus speed curves generated during submaximal IET and may be useful for assessing fitness and monitoring training programs in equine athletes.

Small intestine strangulation by components of the spermatic cord in two geldings.

Two adult Quarter Horse geldings were evaluated for signs of abdominal pain. Both horses had signs of depression and distended small intestines on abdominal palpation per rectum. Abdominal exploratory surgery was performed on both horses. In each instance, small intestine was found to be strangulated by components of the spermatic cord. Both horses were euthanatized because of a poor prognosis. Although not commonly observed, incarceration of intestine by components of the spermatic cord should be considered as a cause of small intestine strangulation in male horses. Early recognition of this condition would have increased these horses' chances of survival.

Technical note: machine milking of sows--lactational milk yield and litter weights.

This study was designed to 1) determine milk yield of sows that were machine milked; 2) assess the effects of pulsation rate, pulsation ratio, and pig removal on milk yield; and 3) assess litter weights. In Exp. 1, four sows were milked daily to 60 d postpartum. There were differences (P < .05) in milk yield among sows, the greatest being 1,898 mL/d. Daily milk yield peaked between 15 and 25 d postpartum. Litter weights were 18.0 +/- 1.0 kg at farrowing and 60.8 +/- 12.1 kg at d 60. In Exp. 2, four sows were milked daily for 28 d. Pulsation rate and ratio (150/min and 28:72, milk:rest, and 60/min and 50:50) were alternated on a daily basis and pigs were isolated for either 0 or 60 min before milking. The higher pulsation rate resulted in more milk per milking (202 +/- 13 vs 168 +/- 13 mL; P < .05). Pig removal resulted in 221 +/- 11 vs 148 +/- 14 mL milk (P < .01). Pig removal times and pulsation characteristics affect the amount of milk obtained, but milk removal from sows has a severe effect on litter weight. This system can be used to harvest sow's milk for pharmaceutical purposes, but supplementation of the pigs is necessary.

Influence of pig substitution on milk yield, litter weights, and milk composition of machine milked sows.

This study was conducted to 1) determine milk yield of sows that were machine milked up to four times daily; 2) determine the effect of pig substitution on milk yield; 3) assess litter weight changes for sows that are milked; and 4) determine milk composition. Eight sows were milked four times daily to d 51 postpartum. Sows either maintained their own litter or had a week-old replacement litter to replace 25-d-old pigs. Individual gland milk yields were obtained on random days throughout lactation, and different diameter and weighted teat cups were rotated so that all glands received all combinations. Composite milk samples were analyzed for fat, protein, and somatic cells. Milk yields peaked at about 19 d postpartum and declined to 45 d postpartum in sows with their own litter, whereas milk yields peaked earlier and had a more dramatic decline after fostering of a younger litter. Litter weights were 17.1 +/- 1.0 kg at farrowing with 13.6 +/- .6 pigs born alive. Final litter weights were 34.4 +/- 11.7 kg for sows with replacement litters and 74.4 +/- 13.5 kg for sows with their own litters, and numbers of pigs weaned were 6.5 +/- 1.3 and 9.7 +/- 1.5, respectively. Milk fat was influenced by route of oxytocin administration (6.53 +/- .12 for i.v. vs 7.21 +/- .19% for i.m. administration; P < .05). Milk fat percentage was highest on d 2 and declined to 13 d postpartum. Milk protein was influenced by time of day of milking (lowest at the fourth milking, 5.57 +/- .11%) and followed a pattern similar to that for milk fat. Milk protein was affected in a linear manner by milk yield, with highest protein associated with lowest milk yields. Somatic cells in milk were influenced by litter replacement (P < .05) and oxytocin administration (P < .01). There was a linear increase in somatic cells from about 8 x 10(6) cells/mL milk at d 2 to more than 12 x 10(6) cells/mL milk at d 51 postpartum. These results show that pig replacement affects the amount of milk obtained. Moreover, milk composition changes throughout lactation. However, milk removal from sows has a severe impact on litter weight gains, and in systems where sow's milk is needed for commercial purposes, pig supplementation is necessary.

Cryptosporidiosis in a black bear in Virginia.

Cryptosporidiosis has not been previously reported in black bears in North America, either free-roaming or captive. However, oocysts have been documented in two captive Malayan sun bears (Helarctos malayanus) located in zoological parks in Taiwan. Developmental stages of Cryptosporidium parvum were observed in tissue sections from the small intestine of a black bear cub found dead in Virginia (USA).

Evaluation of a technique to occlude the internal carotid artery of horses.

OBJECTIVE: To evaluate an occlusion technique for the internal carotid artery of horses using an intravascular, detachable, self-sealing, latex balloon distally and ligatures proximally. STUDY DESIGN: Experimental study. ANIMALS: Six healthy adult horses. METHODS: In each horse, the left internal carotid artery was occluded by placement of an intravascular, detachable, self-sealing, latex balloon distally and two ligatures proximally. Radiographs were taken on days 2, 5, 10, and 30 after surgery to evaluate balloon inflation and position. Endoscopic examination of the left guttural pouch was performed 10 days after surgery to evaluate the integrity of the internal carotid artery and surrounding tissues. At 30 days, the left and right, common, internal, and external carotid arteries were examined grossly and then processed for histologic evaluation. RESULTS: Immediate and long-term occlusion of the left internal carotid artery was achieved in all horses. The surgical procedure was technically straightforward and no intraoperative or postoperative complications were encountered. The balloons remained inflated and in their original position throughout the study. Maturing to mature, organized thrombi were present in the left internal carotid artery in all horses at 30 days. The cerebral arterial circle and common carotid artery were patent at their junctions with the internal carotid artery in all horses. CONCLUSIONS: Use of an intravascular, detachable, self-sealing, latex balloon distally and ligatures proximally is an effective technique for occluding the internal carotid artery of horses. CLINICAL RELEVANCE: This technique may be useful for prevention of fatal hemorrhage in horses with lesions of the internal carotid artery.

Urinary bladder marsupialization for treatment of obstructive urolithiasis in male goats.

OBJECTIVES: To describe a surgical procedure for urinary bladder marsupialization and to report the results obtained from its use in the treatment of obstructive urolithiasis in male goats. STUDY DESIGN: Retrospective evaluation. ANIMALS OR SAMPLE POPULATION: Male goats with obstructive urolithiasis. METHODS: Medical records of male goats that had urinary bladder marsupialization for the treatment of obstructive urolithiasis were reviewed. Data retrieved from the medical records included signalment, postoperative treatment, duration of hospitalization, and short-term and long-term complications. Median values for measured variables were calculated. RESULTS: A total of 18 of 19 goats survived. Urinary flow was re-established in all 19 goats at the conclusion of surgery. Short-term postoperative complications (bladder mucosal prolapse and death) were observed in 2 goats. Long-term postoperative complications (cystitis and fibrotic stomal closure) occurred in 2 animals. Median duration of hospitalization was 4 days. At the time of follow-up, mild urine scald was reported for all goats. Clinical signs of upper urinary tract disease or obstruction were not reported. A total of 15 of 17 owners were satisfied with the procedure. CONCLUSIONS: Urinary bladder marsupialization provided long-term resolution of urinary outflow obstruction in all goats with acceptable morbidity. CLINICAL RELEVANCE: Urinary bladder marsupialization is a procedure that provides a good prognosis for long-term resolution of obstructive urolithiasis in male goats.

Diaphragmatic hernia repair in three young horses.

OBJECTIVE: This clinical report describes surgical correction of diaphragmatic hernia in three young horses. STUDY DESIGN: Retrospective investigation of medical records and subsequent racing performance. ANIMALS: Three young horses with diaphragmatic hernia. RESULTS: Three young horses with signs of abdominal pain had diaphragmatic hernia causing small intestinal strangulation. The strangulated small intestine was resected and an end-to-end jejuno-jejunal (two horses) or a side-to-side jejuno-cecal anastomosis (one horse) was performed. Diaphragmatic hernias were closed with a continuous suture pattern. All horses recovered and raced. No difference in race records was found between the subject horses and their siblings. One subject horse died of colic at 5 years of age, but the cause of the colic was undetermined. The remaining two horses are in use as broodmares and have produced multiple foals without recurrence of signs of diaphragmatic hernia. CONCLUSIONS: Diaphragmatic hernias can be repaired in horses. These horses can achieve race records similar to their siblings and can produce foals without recurrence of signs of diaphragmatic hernia.

Intra-articular anesthesia of the distal interphalangeal joint alleviates lameness associated with the navicular bursa in horses.

OBJECTIVE: To determine if intra-articular anesthesia of the distal interphalangeal joint could alleviate lameness associated with the navicular bursa in horses. STUDY DESIGN: Experimental investigation. ANIMALS: Six clinically normal horses. METHODS: Lameness was induced in each horse by injecting either the left or right front navicular bursa with 5 mg of amphotericin-B. Forty-eight hours later each horse was videotaped walking and trotting before, and 5, 30, and 60 minutes after injecting the distal interphalangeal joint of the treated limb with 5 mL of 2% mepivacaine hydrochloride. All video recordings were then rerecorded onto master tapes in a random sequence. Four clinicians, unaware of the animal identity related to observation time or limb treated, independently viewed these tapes and graded the lamenesses. RESULTS: There was a significant reduction in lameness 5 and 30 minutes after anesthetic was injected into the distal interphalangeal joint. Lameness scores 60 minutes after anesthetic administration were not significantly different than baseline values. Gross pathological examination confirmed marked inflammation of the treated navicular bursae and normal appearance of the distal interphalangeal joints. CONCLUSIONS: Intra-articular anesthesia of the distal interphalangeal joint can alleviate lameness associated with the navicular bursa. CLINICAL RELEVANCE: Intra-articular anesthesia of the distal interphalangeal joint is not specific only for lameness originating in the distal interphalangeal joint.

Systemic and local effects associated with long-term epidural catheterization and morphine-detomidine administration in horses.

OBJECTIVE: The purpose of this study was to determine the systemic and local effects associated with long-term epidural catheterization and epidural morphine-detomidine administration in horses. STUDY DESIGN: Development of systemic or local effects was assessed by placing caudal epidural catheters in study horses and administering injections through the catheters every 12 hours for 14 days. ANIMALS: Ten horses with epidural catheters that received daily injections; six uncatheterized horses presented for euthanasia. METHODS: Horses received either 0.2 mg/kg morphine sulfate and 30 micrograms/kg detomidine hydrochloride or an equivalent volume of physiologic saline solution through epidural catheters. Systemic effects were compared between control and treatment horses by measuring physical parameters and hay and water consumption, as well as by evaluating major organs after euthanasia. Local effects were studied by examining cerebrospinal fluid and by grading representative samples of the spinal cord and surrounding tissues histologically for inflammation and fibrosis. Local effects were compared between control and treatment horses, as well as between catheterized (control plus treatment) horses and uncatheterized horses. RESULTS: No significant difference was identified in daily variables or hay and water consumption between control and treatment horses. No growth was obtained from cerebrospinal fluid cultures. No significant difference in cerebrospinal fluid values or spinal tissue inflammation or fibrosis grades was shown between control and treatment horses. However, when compared with uncatheterized horses, cerebrospinal fluid red blood cell values were marginally higher and protein concentrations were significantly higher in the catheterized group. Lumbosacral and sacral spinal tissue segment inflammation grades, and sacral segment fibrosis grades were significantly higher in catheterized horses. CONCLUSIONS: Long-term epidural administration of a morphine-detomidine combination is not associated with apparent adverse systemic effects in horses. Localized inflammation and fibrosis seem to be catheter-related. CLINICAL RELEVANCE: Potential systemic and local effects are important considerations with long-term administration of a morphine-detomidine combination through indwelling epidural catheters for alleviation of chronic musculoskeletal pain in horses.

Efficacy of an epidural combination of morphine and detomidine in alleviating experimentally induced hindlimb lameness in horses.

Amphotericin B-induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 micrograms/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural injection for a total of 6 hours, heart and respiratory rates were recorded, and horses were videotaped walking and trotting. At the end of the observation period, video recordings were scrambled onto a master videotape. Lamenesses were scored by three investigators unaware of group assignment or treatment time. Lameness scores, heart rates, and respiratory rates were compared between groups using repeated measures analysis of variance. There was a significant decrease in lameness score after treatment with epidural morphine and detomidine (P = .0003); average lameness scores of treated horses were less than grade 1 at each hourly observation for 6 hours after drug administration. Early in the observation period, heart rates significantly increased in control horses and decreased in treated horses (P = .03). A similar trend occurred for respiratory rates (P = .07). Results of this study demonstrate that epidural administration of a combination of morphine and detomidine is capable of providing profound hindlimb analgesia in horses.

Use of a type II external skeletal fixator for repair of delayed union in three calves with forelimb fractures.

Three calves, 3 to 6 months old, were admitted for evaluation and treatment of fractures of the forelimb that had resulted from use of forced extraction at birth. Each of these calves had clinical and radiographic evidence of delayed union of a fractured metacarpus. All calves were treated, using a type II external skeletal fixator consisting of 0.25-inch-diameter transcortical pins and acrylic connecting bars. Two calves required open reduction of the fracture to obtain anatomic alignment of the limb. On the basis of the 3 calves described here, it would appear that type II external skeletal fixators may be adequate for treatment of selected calves with delayed union of a fracture.