Vancomycin kinetics in plasma and synovial fluid following intravenous administration in horses.

Vancomycin hydrochloride was infused intravenously (i.v.) over a 30-min period in five horses at doses of 6.6, 11.0 and 15.4 mg/kg. Vancomycin concentration in plasma and synovial fluid samples was measured using a polarization immunoassay. A pharmacokinetic model was developed to accommodate the special features of the present study. The data were described by a two compartment open model with synovial fluid as an additional compartment in exchange with plasma. Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) were measured for Staphylococcus aureus and Enterococcus sp. using isolates from hospital patients. Based on the pharmacokinetic model and MIC/MBC data, a practical therapeutic protocol for vancomycin administration was established at doses of 4.3-7.5 mg/kg given as a 1-h infusion every 8 h.

Intraluminal hemorrhage from small intestinal ulceration in two cows.

Two adult Holstein cows were admitted with signs of acute gastrointestinal hemorrhage. Abomasal ulceration was diagnosed tentatively in both cows, but was later ruled out in 1 cow that had an abomasotomy performed through a right paramedian approach. Both cows failed to respond to treatment of blood loss and hypovolemic shock and became recumbent; one cow died and the other was euthanatized. Post-mortem examination determined the source of hemorrhage in both cows to be ulcerated small intestine with severe intraluminal hemorrhage. The cause of ulceration was undetermined. Small intestinal hemorrhage should be considered in cattle with signs of acute gastrointestinal hemorrhage.

Ileal diverticulum as a cause of chronic colic in a horse.

A 4-year-old Thoroughbred gelding with a history of chronic colic was referred for evaluation of signs of abdominal pain. Exploratory laparotomy revealed a diverticulum of the distal portion of the ileum located between the layers of the mesentery. The diverticulum was similar in location and appearance to acquired ileal diverticula described in human beings. Complete bypass of the diverticulum by ileocecostomy resulted in apparent resolution of the chronic colic in this horse.

Effects of a histamine type-2 receptor antagonist (BMY-25368) on gastric secretion in horses.

The effects of a potent new histamine-2 (H2) receptor antagonist, BMY-25368, were studied on gastric acid secretion in 5 foals from which food was withheld. Doses of 0.02, 0.11, 0.22, and 1.10 mg/kg of body weight were administered IM in a randomly assigned treatment sequence. Following BMY-25368 administration, hydrogen ion concentration was decreased and mean pH was higher than baseline values in a dose-response pattern. At the 0.22 and 1.10 mg/kg doses, the high pH was sustained for greater than 4 hours. The BMY-25368 thus may be useful for treating gastric ulcer disease in horses.

Surgical treatment of a mural teat abscess in a cow.

A 6-year-old multiparous Holstein cow was admitted for evaluation of progressive milk flow obstruction of one quarter of the udder. Physical examination findings suggested the presence of a mural teat abscess. Ultrasonography substantiated the physical examination findings and delineated the extent of the lesion. Surgical excision of the abscess en bloc yielded satisfactory functional and cosmetic results.

Erysipelothrix rhusiopathiae-induced septic arthritis in a calf.

A 14-week-old Holstein heifer with a 48-hour history of left tarsocrural joint effusion was referred for evaluation when lameness developed 24 hours after needle aspiration was attempted at the farm. Results of synovial fluid analysis were compatible with diagnosis of septic arthritis, and bacteriologic culture of the fluid yielded Erysipelothrix rhusiopathiae. The calf responded to tarsocrural joint lavage and penicillin G administration.

Third-degree perineal lacerations and rectovestibular fistulae in cattle: 20 cases (1981-1988).

The case records of 20 cows with either a third-degree perineal laceration or rectovestibular fistula were reviewed to ascertain the signalment, history, treatment, and long-term result of treatment. Fifteen cows, including 10 first-calf cows, had third-degree perineal lacerations that occurred at calving. Surgery was done in 14 of 15 cows; 10 of the 14 (71%) remained fertile. The cow that was not treated surgically was culled after 24 months because of infertility. Five cows had a rectovestibular fistula; 4 of these were treated surgically. The cow that did not have surgery healed by second intention and remained fertile, and 3 of the 4 cows in which surgery was performed were fertile. None of the cows that produced calves after the initial injury suffered a perineal laceration at subsequent calvings. Single-stage surgical repair of third-degree perineal laceration or rectovestibular fistula appeared to have a good prognosis for subsequent fertility in cows.

Intestinal atresia in calves: 22 cases (1978-1988).

A retrospective study of 22 calves afflicted with intestinal atresia was performed to determine typical signs of disease, treatment, and survival rate. All 22 calves, except 2 heifers with atresia ani and rectovaginal fistula, were examined when they were between 1 and 10 days old because of depression, anorexia, abdominal distention, and lack of feces. All calves had been observed to stand and suckle shortly after birth. Survival rate was influenced by the atretic segment affected: 0% (0/2 surgically treated) for atresia jejunal; 42% (5/12 examined) or 71% (5/7 recovering from general anesthesia) for atresia coli; and 63% (5/8 examined) or 71% (5/7 surgically treated) for atresia ani. Survival appeared to depend principally on early recognition, anatomic site affected, and successful surgical establishment of a patent intestinal tract.

Colopexy of the equine large colon: comparison of two techniques.

A study was designed to evaluate 2 colopexy techniques (A and B) in 8 clinically normal horses to determine which technique would prevent recurrence of large-colon displacement and/or volvulus. For technique A, 35 cm of the lateral free band of the left ventral colon was sutured to the abdominal wall, 6 cm to the left of ventral midline. For technique B, the medial free band of the left ventral colon was sutured to the medial free band of the right ventral colon, and 8 cm of the lateral free band of the left ventral colon was sutured to the abdominal wall, 6 cm to the left of ventral midline. One horse from each group was euthanatized at 6 months, and another at 12 months after surgery. The position of the large colon, the integrity of the colopexy, and other adhesions within the abdominal cavity were evaluated. At necropsy, attempts were made to manually create displacement and volvulus of the large colon. The remaining horses in each group were anesthetized 6 months or 12 months after surgery, and the integrity of the colopexy was evaluated. After a 60-day recovery period, these horses were exercised for 2 months. Although each horse initially lost weight, the weight of all but 2 was acceptable at the conclusion of the study. Two horses that had technique-B colopexies had progressive weight loss serious enough to warrant euthanasia. Both colopexy techniques prevented manual creation of large-colon displacement and large-colon volvulus centered at the sternal and diaphragmatic flexures. Technique-A colopexy also prevented manual creation of volvulus of the large colon centered at its base.(ABSTRACT TRUNCATED AT 250 WORDS)